This year's CEDAR student workshop centered on the topic of incoherent scatter. The technical part of the workshop was divided into two halves, the first focussing on the theory and practice involved in incoherent scatter measurements and the second focussing on the coordinated science that revolves around the large incoherent scatter radar (ISR) observatories. The goal of the workshop was to give an introduction to incoherent scatter for the broad range of students that attend the CEDAR meeting. ISRs are of course fundamental instruments in the CEDAR community for studies of the upper atmosphere and ionosphere. ISRs are central instruments within observatories that conduct a diverse range of atmospheric and ionospheric science (hence the 'coordinated science'). In addition, the Advanced Modular ISR (AMISR) project has opened up exciting new opportunities for incoherent scatter and coordinated science.

After a brief introduction from Jan Sojka (on behalf of the CSSC) and Rich Behnke (on behalf of the NSF), Bob Robinson (NSF) gave the first tutorial, an introduction to the history of ISRs entitled "Incoherent Scatter Radars: Past, Present, Future". The talk was comical and engaging with a positive outlook on the future of incoherent scatter in the CEDAR community, focussing of course on the blossoming global chain of ISRs exemplified by the AMISR project. John Sahr (University of Washington), the keynote speaker, gave the first technical tutorial, which was "Introduction to Ionospheric Radar Remote Sensing". The talk was very well received, covering the basics of radar for students not familiar with the field and with some advanced material that engaged the more experienced students. The second tutorial was given by Josh Semeter (Boston University) and Phil Erickson (Millstone Hill Observatory) with an outline. That tutorial focussed first on the theory of incoherent scatter, which was presented briefly by Josh building up on John Sahr's general introduction. This aspect of the tutorial dealt with a difficult topic to cover in a short time period, but was effective in getting across important information by using illustrative examples to emphasize difficult concepts. The second part was an interactive introduction presented by Phil where data from the Millstone Hill ISR was analyzed in real- time to emphasize different concepts, such as incoherent averaging and the effects of different waveforms. This aspect of the tutorial was well received and effective in engaging the audience. Given its success this year, the interactive approach may be one to use again in future workshops.

After a tryptophan lunch, we reconvened for the second half of the workshop, which focussed on incoherent scatter coordinated science. This part of the workshop consisted of shorter tutorials covering a more diverse set of topics. John Kelly (SRI International) opened the session by introducing the AMISR project. The talk focussed on the plans and capabilities of the new system as well as how students could get involved in the project. Jeff Thayer (University of Colorado) gave a tutorial on "IS Coordinated Science at High Latitudes". Aptly titled "A Broad Perspective from a Narrow View", Jeff showed how ISRs can combine with satellites, all-sky and narrow- field cameras, and distributed instrumentation to do illuminating science on varying spatial and time scales, which is essential in the high latitude environment. He also referred to an "ISR Fact Sheet". Jorge Chau (Jicamarca Observatory) gave on a tutorial on "ISR Coordinated Science at Equatorial Latitudes". Koki gave an overview of the capabilities of the Jicamarca facility, showing how the radar can be configured in different ways to study different aspects of the stable and unstable ionosphere. He further showed how Jicamarca data can be combined with satellite, optical, rocket, and other radar data to do multi-instrument coordinated science. Sixto Gonzalez (Arecibo Observatory) gave a similar talk representing coordinated science at low latitudes, showing the different science that can or has been done at the Arecibo Observatory by combining ISR data with the heater, with all-sky imagers, with lidar systems, etc. The final tutorial on coordinated science was given by Anthea Coster (Millstone Hill Observatory) who spoke from her perspective at mid-latitudes, showing how Millstone Hill ISR data can be combined with varying datasets from coherent scatter radar data to model results. One noteworthy example is the use of Millstone Hill data in combination with total electron content data over North America to examine the details of ionospheric storms and storm enhanced density plumes. Anthea closed with an introduction to the Madrigal database.

The final part of the workshop was organized by Elizabeth Kendall (SRI International). Elizabeth solicited contributions from students who were presenting posters on topics relating to incoherent scatter and ISR coordinated science. About 20 students presented a slide and a brief introduction to their work, to be presented in more detail in the poster sessions in the coming days. This session was an excellent way of getting a feel for what kind of research the students were doing and was a nice conclusion to the day. Feedback forms were passed out to the students and the responses were in general very positive. Talks are available online at http://cedarweb.hao.ucar.edu/workshop/archive/2006/wklist_2006.html#Nicolls.

Tuesday 20 June

10:00-11:30 AM (plenary workshop ~250, continued during pizza lunch 1145-1245 on Friday ~75)

(Anasazi) Frontiers in CEDAR Science: A workshop to develop campaigns that advance the frontiers in CEDAR Science, with conveners Richard Collins (University of Alaska, rlc@gi.alaska.edu) and Eric Donovan (Universiy of Calgary, eric@phys.ucalgary.ca) and panelists Anthea Coster (MIT/Haystack) Eric Donovan (University of Calgary), Cassandra Fesen (Dartmouth College), and Michael Kelley (Cornell University)

The CEDAR Science Steering Committee (CSSC) recognize the fact that much of the progress in CEDAR science has been associated with organized campaign studies. Recent community reviews and assessments have shown that campaign studies are associated with increases in the number of published studies and enhanced collaboration between investigators.

Acting on behalf of the CSSC the conveners invited members of the CEDAR community to identify new frontiers in CEDAR science that could spur new campaign initiatives. Community members were invited to submit their concepts to the convener before the CEDAR meeting and these were posted to a public website that remains accessible at http://www.gi.alaska.edu/splidar/CEDAR.html

The conveners organized the submissions into four broad areas and four summary talks. The summary talks and presenter were;

1. "Ionosphere, Magnetosphere and Thermosphere", Anthea Coster,
2. "Middle and Lower Atmosphere", Michael Kelley
3. "Validation and Assimilation", Cassandra Fesen,
4. "The Global View", Eric Donovan

These talks were presented on Tuesday morning in the plenary session. The conveners and panelists hosted a follow-up lunch town-hall meeting on Friday.

The community submissions and discussion highlighted the following questions;

1. How will the CEDAR community better coordinate the use of increasingly accurate and high-resolution models (e.g. WACCM) in planning key observational studies?
2. How will the CEDAR community respond to societal needs to predict and forecast the state of the middle and upper atmosphere?
3. How can the CEDAR community foster better collaboration between US and international investigators to comprehensively address global challenges?
4. How can the CSSC better structure the annual workshop to facilitate the development of new CEDAR community-driven campaigns?
5. Should the CSSC chair and NSF staff host a town-hall meeting to discuss current issues at the end of each annual workshop?

13:00-15:00 PM1

(Anasazi South, 66) Equatorial Ionosphere and Scintillation Workshop, with conveners Odile de La Beaujardiere (AFRL, odile.delabeaujardiere@hanscom.af.mil), David Anderson (NOAA), Chin Lin (Boston College), David Hysell (Cornell University), Michael Kelley (Cornell University), Jorge Chau (Jicamarca Radio Observatory)

(Anasazi North, 52) Ground-Based Coordination with the AIM Satellite Mission, with conveners Michael J. Taylor (Utah State University, mtaylor@cc.usu.edu), James M. Russell III (Hampton University), and Scott Bailey (Virginia Tech)

The Aeronomy of Ice in the Mesosphere (AIM) mission is a new NASA Small Explorer satellite designed specifically to investigate "why polar mesospheric clouds form and why they vary". Polar mesospheric clouds (PMC) are of considerable importance to the CEDAR program as they form and grow under exceptionally cold conditions (temperatures below ~150 K) that are present only in the summer months at high-latitudes when the mesopause region is driven far from thermodynamic equilibrium by strong upwelling. The AIM mission is currently scheduled for launch in April 2007 and will make measurements in both the northern and southern hemisphere summer seasons over the following two years. Ground-based observations in coordination with AIM measurements will enhance significantly the scientific potential allowing new objectives to be addressed as well as cross validation. Our goal for this first workshop was to introduce the AIM program and science team to interest researchers in the CEDAR ground-based community to develop new collaborations and to begin planning for coordinated observations during the AIM mission. These measurements are especially timely with the upcoming International Polar Year (2007-08) and the much heightened scientific and public interest in these clouds as possible harbingers of climate change.

AIM will make the first simultaneous measurements of mesospheric temperature, H2O, PMC content (and other trace gasses and aerosols) at high-latitudes essential for quantifying PMC formation. The data will be obtained by three instruments: SOFIE (Solar Occultation For Ice Experiment), an IR solar occultation differential absorption radiometer; CIPS (Cloud Imaging and Particle Size experiment), a panoramic UV imager comprising four cameras; and CDE (Cosmic Dust Experiment) that will detect and measure in-situ dust particles. The workshop was divided into two parts with presentations by the AIM PI (Dr. Jim Russell) who described the basic mission and overarching science goals, and several of the AIM Science team members (Drs. Dave Rusch, Mark Hervig and Scott Bailey) who presented details on the flight instrumentation and their measurement capabilities. This was followed by a very interesting and lively "open forum" discussion that concentrated on gaining more details about AIM science and the planned operations in both hemispheres. Several short presentations by interested researchers were also made broadening the fundamental capabilities of the AIM mission. The workshop concluded with a discussion on the initial planning for ground-based coordinated measurements and a list was circulated to interested researchers to sign on for more information as the mission moves towards launch. Overall a well attended and very informative new workshop.

(Sunset, 38) Sensitivity Study in Global Thermosphere/Ionosphere Simulations and Comparison with Observations, with conveners Yongliang Zhang (APL/JHU, yongliang.zhang@jhuapl.edu), Wenbin Wang (NCAR, wbwang@ucar.edu)

This workshop was held to explore how inputs (such as joule heating rate and auroral hemispheric power) affect the results from the global thermosphere/ionosphere simulations (such as TIMEGCM) as well as how we can use ground/satellite observations to improve the model inputs, and what we have learned from the community?s modeling efforts. The 2-hour workshop ran for approximately 2.25 hours with an average attendance of about 43 people.

After a brief introduction by Yongliang Zhang, Wenbin Wang (High Altitude Observatory, National Center for Atmospheric Research) gave the first talk on the coupled magnetosphere and ionosphere thermosphere model (CMIT) and showed the electron densities variations simulated by CMIT during the April 2004 geomagnetic storm event. The ionospheric electron densities from CMIT were compared with the observations (CHAMP, Digisonde, TIMED/GUVI, Millstone radar) and GAIM outputs. He concluded that (1) the CMIT model significantly underestimates electron density at the equatorial anomaly during both storm and quiet times, (2) at middle and high latitudes the modeled electron densities agree with the observed electron densities both in distribution and magnitude, (3) the model predicts much less extension of the equatorial anomaly into the nighttime, this is probably due to the underestimation of the daytime equatorial anomaly by the model, and (4) more data are needed to validate modeled high latitude inputs: convection pattern, precipitation (energy flux and its location).

Geoff Crowley (ASTRA) compared the thermospheric O/N2 ratio from TIMEGCM runs with GUVI O/N2 for the November 21, 2003 superstorm. Two kinds of AMIE outputs (traditional and improved) were used to specify the auroral inputs in the TIMEGCM. The improved AMIE was able to improve the agreement between TIMEGCM and GUVI O/N2 in the northern hemisphere. However, the rapid recovery seen in GUVI O/N2 was not reproduced in the simulated O/N2. Geoff concluded that (1) accurate representation of high latitude inputs are required for high-fidelity global modeling, (2) high latitude inputs are difficult to obtain, (3) AMIE provides a good approximation to the potential pattern, but there?s never as much data as we?d like for assimilation, (4) particle inputs are more difficult to model or include, and (5) more ground-based and satellite observations are required.

The third talk was given by Yongliang Zhang (Johns Hopkins University Applied Physics Laboratory). He reported on the use of GUVI auroral data to develop an empirical auroral model. This model gives a better estimate of auroral hemispheric power (HP) compared to NOAA HP. He found that the HP value that was used in the TIMEGCM and from the magnetosphere model is typically only ¬ of the GUVI HP. He compared the O/N2 from Coupled Magnetosphere Ionosphere and Thermosphere (CMIT) model with GUVI O/N2 during two storm events (April, 2004 and May 2005). In summary he found that (1) the difference in north/south hemispheric power and Joule heating combined with the seasonal effect can qualitatively explain the GUVI O/N2 observations, (2) the CMIT model was able to reproduce general features in GUVI O/N2. However, the extended O/N2 depletion regions in the model results are very likely due to an over estimate of the joule heating rate, and (3) there is a plan to run CMIT with smaller joule heating rates (100%, %80% model values) and/or larger HP to see how this will improve the agreement with GUVI observations.

Alan Burns (High Altitude Observatory, National Center for Atmospheric Research) presented a brief discussion of how the high latitude Joule heating changes the global neutral wind circulation which, in turn, induces global changes in neutral composition.

Ludger Scherliess (Center for Atmospheric and Space Sciences, Utah State University) presented the specification of ionospheric drivers in GAIM. The drivers include (1) high latitude convection and precipitation, (2) low-latitude electric field, (3) global neutral wind, and (4) global neutral composition. He showed a few cases where GAIM, using the Kalman Filter technique, provides better results (ionospheric electron density) than climate model does. He also suggested that the difference between GAIM and Ionosonde electron density profiles could be due to errors in temperature and/or different assumptions of profile shapes used in ionogram inversion.

Yue Deng (University of Michigan) showed the results from the Global Ionosphere-Thermosphere Model (GITM) runs. She found that the O/N2 from GITM is very sensitive to the neutral-neutral friction, eddy diffusion, and numerical flux. However, O/N2 from GITM with current, preliminary, selection of the coefficients is quite different from TIMED/GUVI O/N2.

Xiaohua Fang (University of Michigan) discussed the impact of global high energy (30-240 keV) proton precipitation on NO and electron density during magnetic storms. He used the ionization and heating rate from a 3-D Monte Carlo ion transport model as high latitude inputs to the Global Ionosphere-Thermosphere Model (GITM). He found that the energy power carried by protons was comparable to that by electrons during the storm on December 5, 2004.

Trevor Garner (Center for Space Science, The University of Texas at Dallas) discussed the variability and correlations in the topside ionosphere (electron density) based on DMSP measurements. He found that (1) the topside densities tend to obey a three-parameter log-normal distribution rather than a normal distribution, (2) the shape parameter has a north-south asymmetry and peaks near the equator, and (3) the densities increase with solar activity.

The conveners wish to thank all who attended and participated in the workshop discussions.

(Zia, 20) Continuing on Towards an Integrated Data Environment with the Virtual Observatories with conveners Michele Weiss (JHU/APL, michele.weiss@jhuapl.edu), John Holt (MIT Haystack Observatory, jmh@haystack.mit.edu), Peter Fox (NCAR, pfox@ucar.edu), Daniel Morrison (JHU/APL, Daniel.Morrison@jhuapl.edu), Stuart Nylund (JHU/APL, Stuart.Nylund@jhuapl.edu)

The goal of this workshop was to bring together user-scientists, existing data center representatives, and representatives of the new domain specific Virtual Observatories to engage in a discussion of how the new Virtual Observatories can best serve the user community and integrate with existing data centers and model providers. Approximately 18 - 20 people attended this session.

The session started out with the introduction and first talk by Peter Fox (NCAR) on the Virtual Solar Terrestrial Observatory (VSTO). He provided an introduction to the upcoming EGY in 2007-2008 ( http://www.egy.org). The EGY has a working group on Virtual Observatories (VOs) that the community should support. His talk provided a definition and an introduction to Virtual Observatories. The VSTO is nearing operational stage and will integrate the CEDAR database, CISM, and resources from Mauna Loa Solar Observatory. Further information is available from http://vsto.hao.ucar.edu/.

Daniel Morrison (APL/JHU) provided the next talk on the Virtual Ionosphere Thermosphere Mesosphere Observatory (VITMO) one of the newly announced NASA domain specific VxOs. This system will tie together ground based data sets such as SuperDARN and satellite data from TIMED, AIM, SNOE, C/NOFS, UARS, and DMSP. It will also integrate with data sets and facilities from CDAWeb, SSCWeb, and ModelWeb at the Space Physics Data Facility at NASA Goddard. In addition, the VITMO like all of the other VxOs plan on cross connecting to each other.

Bill Rideout (MIT Haystack Observatory) provided an introduction to Madrigal that is used extensively at many radar installations. Madrigal is an open source system and represents perhaps the first Virtual Observatory for the Space Physics community. This system ties together Millstone Hill, Arecibo, EISCAT, Jicamarca, SRI International, Cornell University, and others. The basic data format is the same as the format used in the CEDAR database. A good discussion followed about the use of the format and the Madrigal software as a standard for other ground based sites including those with optical imagers.

Tony van Eyken (EISCAT) gave a presentation on AstroGrid: an Astronomy and Solar System VO for Silvia Dalla (Univ. of Manchester). This VO is part of the International Virtual Observatory Alliance ( http://www.ivoa.net) and is focused very much on the concept of "workflows" that may be used over and over to insure that data is analyzed in a consistent fashion. Presented as part of this was a movie on a data discovery tool called HelioScope. HelioScope allowed solar data from the Virtual Solar Observatory (VSO) and space physics data from NASA CDAWeb to be retrieved based on proposed Simple Time-range Access Protocol (STAP).

Eric Donovan (Univ. of Calgary) presented GAIA (Global Auroral Imaging Access) for accessing auroral imagery from ground and space. GAIA is being developed by an international consortium for integrating data from the world-wide networks of optical instruments and riometers ( http://www.gaia-vxo.org).

Masha Kuznetsova (CCMC/GSFC) tied things up with a talk on the Community Coordinated Modeling Center (CCMC) ( http://ccmc.gsfc.nasa.gov) support of science needs for the integrated data environment. The CCMC supports ionospheric models such as CTIP, SAMI-2, and GAIM as well as many others. Because the output of many of the models are extremely large, the system operates in a batch mode, with submission through a user-friendly interface. A discussion followed on how to integrate knowledge of the output from the models into the search capabilities of Virtual Observatories. Discussions were also held on the possibility of "flying a satellite trajectory" through large 3-dimensional model output to simulate instrument observations.

The talks demonstrated that a lot of progress has been made in improving the Integrated Data Environment for users but that a lot of work still needs to be done. A listserv newsgroup for coordinating the VxO activity has been set up at vxo@listserv.gsfc.nasa.gov.

16:00-18:00 PM2

(Anasazi South, 83) New Research Opportunities with the AMISR and Co-Located Instruments at Poker Flat Alaska, with conveners John Kelly (SRI International, kelly@sri.com), Brenton Watkins (University of Alaska, watkins@gi.alaska.edu)

(Sunset, 88) Ionosphere-Thermosphere Research Using Measurements in Space -- What's Needed? What's Possible? What's Realistic? with conveners Joseph Grebowsky (Goddard Space Flight Center, joseph.m.grebowsky@nasa.gov), Robert Pfaff (GSFC)

The two hour workshop had a very engaged, continuous, and significant discussion from the floor. Attendance was standing room only, and would have been more if there were not a coincident workshop on the new NSF AMISR radar that drew away many concerned radar participants.

This workshop was held to address CEDAR science interests in establishing the most significant and compelling Ionosphere-Thermosphere (I-T) scientific problems that can only be resolved with the aid of space-based measurements. One of the chief aims was to begin to develop succinct themes that can be used to effectively articulate the compelling science of the ionosphere-thermosphere region and the importance of the Sun-Earth connection to those outside the I-T community.

Overview of Introductory Material
After a brief introduction and overview by Joe Grebowsky about the NASA I-T spacecraft missions planned in the near and far future and his perception of how the I-T community is viewed with concern by NASA management, Phil Richards followed with a description of potential NASA opportunities for I-T science, including EUV measurements on SDO, perhaps an imager as a Mission of Opportunity resulting from the RBSP AO, and future Explorer opportunities. He gave some guidance on how best to propose I-T missions within the current NASA framework. This led to discussions about the perceived image of I-T science at NASA HQ. The Magnetosphere community approach with MMS and THEMIS were provided as examples of bringing together a broadly-focused group to solve one specific problem. There appeared to be a general appreciation that the most compelling and urgent problems in I-T science, of which there are many, need better definition.

After these general introductions, two brief, invited talks were presented, by Rod Heelis of the University of Texas, Dallas, on I-T needs for science measurements, followed by Tim-Fuller Rowell of NOAA describing the most imperative needs for advancing the models.

Overview of Heelis presentation:
Rod Heelis's presentation focused on the fact that I-T research is not prominent in immediate NASA mission plans and generated much discussion. Rod stressed that both the currently approved I-T missions, GEC and I-TSP, went through extensive mission formulation studies that provided exciting science mission design concepts that both fell below the cost caps that NASA fixed initially for each of the STP and LWS Geospace missions. However, the I-T missions are now disappearing far into the future, given the increased costs of other missions currently under development preceding these I-T missions in the flight program. At a systems level, science progress requires coordination with up-to-date knowledge of the state of the Sun, the interplanetary medium, the magnetosphere, and the ionosphere-thermosphere. With the slipping of the IT missions, the great observatory concept is being lost. It is necessary to define and describe a community initiative that, if coordinated now with planned NASA missions, could vastly improve the scientific productivity.

To illustrate his main point, Heelis stated that storm-time perturbations in ion number density at low and middle latitudes can be dramatic during daytime AND nighttime. Electric field and neutral wind changes are required to explain these perturbations. These perturbations cannot be described separately since they are physically linked through dynamo action and ion drag. The influence of ion-neutral interactions is highly dependent on altitude and temporal persistence. There are little data at a range of altitudes to influence our thinking in this area. We need to undertake an initiative to describe the neutral wind distribution and the accompanying electric field distributions in the thermosphere. Important questions include: What are the relative contributions of the magnetospheric potentials and neutral winds to the E fields at low and mid latitudes? How do the roles of the E x B drifts and neutral winds operate to significantly influence the total ion concentration?

Rod provided a list of his views of what is important and some possible driving themes:

• What is important?
  • We need to define the next thing to do as a single community.
  • No downside to this activity.
  • We should not let space weather be underrepresented.
  • We should put forward a NASA mission accomplished within budget.
  • Urge NASA and community to start this initiative as soon as possible.
• Some possible driving themes:
  • How does the wind blow in the upper atmosphere?
  • How does the ionosphere respond to geomagnetic storms?
  • What is the response of the ionosphere to solar storms?
  • Neutral dynamics.

Overview of Fuller-Rowell presentation:
Tim Fuller-Rowell emphasized that although the Thermosphere-Ionosphere system is perceived as a sluggish system, it is really very dynamic. He further emphasized that there is no observational evidence for the models, in particular for the meridional winds that drive the dynamics and for the dynamo part of the electric field in the mid to low latitude region. There are no measurements that currently show how realistic are the models.

Tim stated that the science in the I-TSP GMDT report is still as relevant today as when the report was published (in 2002). We need measurements to explore: global dynamics and electrodynamics, their relative contributions during quiet and disturbed times, global atmospheric circulation and waves, and closure of electric currents. Many physical conditions require knowledge of the balance between dynamics and electrodynamics. Observations are needed in the range 120-500 km and to understand the dynamic system requires global coverage. Electrodynamics is nominally simpler - quasi-2D field, whereas dynamics is more challenging - 3D field.

Tim then suggested that technology is coming to fruition for multiple nanosats in random orbits to measure winds, ion drifts and composition in situ. With such a system, high failure rates would be tolerated with the focus on quantity not reliability. Data would be combined using data assimilation techniques. He emphasized that we have the tools to combine these already.

Tim's main message: the I-T system is dynamic. Therefore, we need to look at GLOBAL DYNAMICS.

General Discussion
Following these presentations, Rob Pfaff led an open discussion of issues for more than an hour. Many issues were discussed and recommendations for a grand I-T theme were made. Some of the highlights from the discussion follow:

• If you want to attack a global problem, we need a global measurement system. We cannot find out everything from a single orbit with a single local time.
• A truly global, multiple satellite frontier mission (such as the Ionospheric Mappers originally proposed for LWS) needs to be developed. This would enable the design issues be worked in the study phase and it would give the community something on the radar screen.
• The last time we had a satellite with a full complement of neutral and plasma measurements was Dynamics Explorer-2 (1981 launch). This satellite had a low duty cycle (25%), only lasted 18 months, and carried no propulsion (thus limited to its orbit of 300-1100 km).
• We need a wider scope workshop, a 2-day session with wider community involvement. We need to decide what is sellable now and how to sell it. There is also a need for a tiger team for I-TSP/LWS to re-discuss the I-TSP mission - this needs to be done soon.
• We need to carry forth the I-TSP mission for Living With a Star. We may need to update the mission to answer the criticisms, real or perceived. We need to show there is community excitement for I-TSP - this is the mission we are trying to save.
• There is only an upside to encouraging themes and only a downside to shooting down other people's ideas - we need to get a consensus so that we do not all try to shoot down good ideas.
• Most missions talk about in situ measurements but a lot of key measurements are needed at low altitudes (90-120 km) where it is not practical to fly multiple satellites, remote sensing techniques also must be considered.

In the midst of these discussions short-phrased compelling themes were offered to describe some of the most urgent and compelling I-T science that needs to be accomplished:

• What are the relative contributions of magnetosphere potentials and neutral winds to the electric fields at low and mid latitudes?
• How do the roles of E x B drifts and neutral winds operate to significantly influence total ion concentrations?
• What are the neutral winds in the upper atmosphere?
• How does the I-T system respond to solar and geomagnetic storms?
• Map the global dynamics and electrodynamics.
• The dynamics of the upper atmosphere.
• Plasma atmosphere interactions.
• Living with an ionosphere.
• How does the ionosphere influence the magnetosphere?
• Where does the energy in the magnetosphere go?

Finally, here are some additional thoughts that were expressed on the focus of I-T activities:

• (Science) There are traditionally 4 states of matter (solid, liquid, gas, plasma). The 5th state of matter, that which has unique properties in nature yet is poorly understood, is a partially ionized plasma - the ionosphere-thermosphere. We are trying to understand the behavior of ions and neutrals in the same volume, how they respond to outside influences and how they interact. The physics of this general phenomena is captured in our themes, yet we do not have a single word to describe this fundamental aspect of the universe, in a similar way in which the word "reconnection" is used to encompass a fundamental, unifying theme used by the magnetospheric community.
• (Applications) Satellite drag could be a focus for applications. One needs to understand all IT processes in order to deal with the problem of drag, both on the earth as well as other planets, such as Mars. Focusing on drag presents a narrow, yet very important, problem that entails a broad range of science. The magnetosphere community was effective at finding an operational problem - killer electrons - and casting it into the physics which we do not understand. The satellite drag concept could provide such a prime applications focus for the I-T community.

Conclusions of workshop:

1. There are many urgent and compelling science questions in I-T that require space-borne measurements.
2. Among the major science questions for which space measurements are most urgently needed are those of neutral and plasma dynamics, both on a localized and a global scale. There were no disagreements with the importance of understanding this dynamics.
3. The importance of both ITSP and GEC was emphasized.
4. The next steps were not clear. Some favored a tiger team to work on ITSP with NASA HQ in the immediate future and felt this was most important. Others stated that a series of workshops over the next year to develop main themes would be useful.

(Zia, 36) Ionospheric Effects of Lighting, with conveners Ningyu Liu (Pennsylvania State University, nul105@psu.edu), Mark Stanley, Michael Taylor (Utah State University)

19:30-21:30 PM3

(Zia, 45) Midlatitude Nighttime Ionospheric Structures: Theory, Modeling and Physical Explanations, with conveners Jonathan Makela (University of Illinois, jmakela@uiuc.edu), John Mathews (Pennsylvania State University), John Meriwether (Clemson University)

A small evening workshop was held to discuss the current status of our understanding of mid-latitude nighttime ionospheric structures. Despite observations spanning over a decade, the physical mechanism responsible for the development of these structures remains elusive. In this workshop, several presentations were made on the current status of our understanding from optical, radio, and theoretical standpoints. Presenters included Jonathan Makela (U of Illinois), Dave Hysell (Cornell U), Carlos Martinis (Boston U), and Russell Cosgrove (SRI). Many of the observations to date have been made in the Caribbean sector where there is increasing evidence for correlation between the coherent scatter in the E region and banded structure in optical imagery. This matches recent theoretical advances suggesting a coupling between sporadic E instabilities and F-region instabilities.

The participants of the workshop concluded that more coordinated observations are required to solidify our understanding of this connection. Few truly coordinated/collocated observations of both the E and F regions during events of this type have been made to date. Observations from magnetically conjugate locations would also be useful in unraveling the physical processes at play, as the structures may have an effect (or source) in the conjugate hemisphere. Furthermore, we concluded that future experiments should be carried out with instrumentation spread across a wider area to expand the region of the ionosphere simultaneously studied, increasing the likelihood of capturing these events. Experiments combining optical and radio techniques show the greatest promise in measuring the necessary parameters needed to come to a better physical understanding of these nighttime mid-latitude structures.

Wednesday 21 June

13:00-15:00 or 16:00 PM1

(Anasazi to 16:00, 103) Structure and Irregularities in the Mid-Latitude Ionosphere and Thermosphere, with conveners J. Michael Ruohoniemi (APL/JHU, mike.ruohoniemi@jhaupl.edu), Robert Pfaff (Goddard Space Flight Center) and Gregory Earle (University of Texas at Dallas)

The goal of this workshop was to bring together the aeronomy community to focus on the often overlooked irregularities of the mid-latitude ionosphere. The first part of the session was devoted to overviews of the midlatitude domain, while the second part focused on site specific studies and new capabilities. Mike Kelley opened the session by providing an overview of midlatitude TID observations, including data from the Caribbean and the MU radar system. He stressed that the evidence for conjugate structures strongly suggests that the observed plasma density irregularities result from electrical processes, not from gravity waves or TIDs alone. Mike also described the Perkins instability and some of its shortcomings relative to the observational evidence. Charles Seyler followed by discussing some of his recent ideas about a non-Perkins instability that may be effective at midlatitudes, and how gravity wave seeding at specific frequencies may increase the growth rates so that they agree more closely with the observations. Greg Earle then showed statistical data relevant to the seasonal and longitudinal variations of echoes seen from the topside sounder aboard the Japanese ISS-B satellite. He also described an upcoming sounding rocket mission that has a significant ground-based suite of instruments that will focus on midlatitude spread F near Wallops Island, Virginia. Rob Pfaff continued the in-situ discussion by showing a wealth of data from the French Demeter satellite. These data show waves at frequencies up to about 1 kHz correlated with significant plasma density depletions, especially during magnetic storm periods.

Ray Greenwald turned the discussion to radar capabilities by showing some measurements from the Wallops Island component of the SuperDARN system. Among the observations are events showing large drift velocities that are correlated with magnetic disturbances. These are interpreted as auroral events that penetrate into the plasmasphere. The Wallops radar observes low velocity structures as well, along with occasional E-region structures a few hundred kilometers northeast of Wallops. Phil Erickson moved the discussion a bit further north by describing SEDS and SAPS observed from Millstone Hill. The poleward wall of some of the observed depletions may provide fertile ground for instability growth.

Rebecca Bishop led off the second part of the workshop by describing her work on correlations between tropospheric storms and ionospheric responses. Her assembled data from Arecibo and from various ionosondes indicate that some storm systems have very strong ionospheric effects. Rob Redmon briefly commented an a new data archive that is available to scientists interested in ionosonde data such as that used by Rebecca. Geoff Crowley gave a talk about the TIDDBIT tristatic radar system he has developed for identifying TIDs. Geoff showed data taken in Texas, and identified the sites for a temporary redeployment of the system on the east coast in support of Greg Earle's rocket experiment. Geoff's system can measure TID drift speeds and provide vertical and horizontal resolution by using two frequencies simultaneously. Terry Bullett described the new dynasonde system being installed at Wallops Island, which may eventually replace the digisonde currently deployed there. The new system will allow measurement of a structure function, provide improved Doppler velocity data, and will include an echo location visualizer in addition to standard ionogram products. Keith Groves then discussed a midlatitude VHF scintillation facility that will work with the dynasonde to address questions related to small-scale structure associated with midlatitude spread F. Qihou Zhou changed the focus to lower midlatitudes by describing his measurements of intermediate layers using the Arecibo system. He discussed some new ideas about measuring the composition within these tenuous layers during both daytime and nighttime conditions. Trevor Garner closed out the session by discussing TEC maps made from GPS measurements in the southwestern US and in central America. These TEC measurements are quite dramatic during storm events, revealing large gradient structures in the plasma density.

Overall the session was a highly effective introduction to the midlatitude region for the many students and researchers in attendance. There are a number of interesting phenomena that happen primarily at midlatitudes, and much work remains to be done to develop a better understanding of the physical processes involved.

One 'action' item for many people at the workshop is the impending launch of the sounding rocket at Wallops Island as described by Greg Earle. The launch window is 9/26/06 - 10/14/06 and the objective is to fly through a mid- latitude spread F event while making simultaneous measurements from the ground of TEC, TIDs, ionograms, scintillation, and airglow. The rocket itself will measure electric fields, neutral winds, and plasma density along a 140 degree azimuth (SE) from Wallops Island. The ground based data will be used for comparison with the finer scale in-situ measurements, and also for intercomparison on other nights of the window. For example, the ground based imagers and detectors will gather about a month of simultaneous data, independent of the rocket flight. These data will be the first time that many of these instruments have simultaneously made measurements during a midlatitude spread F event. The workshop and follow-up discussions provided opportunities for participants to review the preparations for the experiment and for other interested parties to become involved.

Further enquiries can be directed to Mike (mike.ruohoniemi@jhuapl.edu), Rob (robert.f.pfaff@nasa.gov) or Greg (earle@utdallas.edu).

(Sunset, 43) Data Assimilation in Space Sciences, with convener Mihail Codrescu (NOAA, mihail.codrescu@noaa.gov)

Initially, the 7 panel participants presented 5-minute overviews over their personal view of data Assimilation.

1) Art Richmond viewed Data Assimilation as "Representing a system through a synthesis of observations with a model". He noted that "Data assimilation, when done properly, combines the strength of the observations and the model". He also noted that "Data assimilation requires a thorough understanding of the observations and the model". In particular the limitations and uncertainties of both the model and the data need to be well understood.

Question to Art Richmond: Does time need to be explicitly included in a Data Assimilation system? Answer: If AMIE is a DA system time does not necessarily need to be included.

2) Bob McCoy took the standpoint of what can be learn from meteorologists? He noted that meteorologists use DA to drive the physics by constantly adjusting the initial conditions. In the ionosphere we have large variability on multiple time-scales and various forcing mechanisms. He noted that" DA needs good physics-based models, data with error bars, and fast computers". He added that "many different DA approaches have been developed" and he presented a list of about 10 different techniques. He noted that "meteorologists have more than 5.5 million observations per day for use in their DA models. In the ionosphere, we are approaching about 1 million observations per day".

3) Bob Schunk noted that "DA models need multiple data types with error bars, physics- based time dependent models and a rigorous technique". In this case DA models can give you reliable specifications with error estimates.

4) Cliff Minter talked about DA models from an engineering standpoint and pointed out that "data assimilation" is being heavily used for orbit determination and for example for the determinations of the Earth gravitational field.

5) Gary Bust asked the question whether "Data assimilation can and should be used to answer science questions". He noted that "when theory does not agree with the observations the science is not well understood".

6) Stan Solomon stressed the need for "a broad definition for data assimilation". He noted that "different regions need different definitions". He added that "for example driving a model with ACE data could be considered as Data Assimilation".

6) Tomoko Matsuo noted that "Data assimilation" uses the prior knowledge of the state of the system (empirical or physical model) together with observations". In this concept, she noted, that "Error covariance matrixes are being used". She stressed that "Data assimilation" systems can help in the design of observing systems". In space weather the observations are sparse, the system is dissipative and strongly forced, i.e. not sensitive to perturbations in initial or boundary conditions. Some operational centers are extending their tropospheric data assimilation schemes to the mesosphere and lower thermosphere and we will have to meet them.

Several questions were raised after the initial presentations of the panel members.

How do we know that inferred quantities like the winds are correct? It was noted that multiple data types are important to obtain winds from data assimilation models. In particular, information about the height of the ionosphere (hmF2) is needed. The inferred quantities need to be compared with actual observations where possible.

Which role can incoherent scatter radars play in data assimilation? It was noted that ISRs are not operating continuously and therefore cannot be used as operational data sources. However, they are the best instruments for validation. Furthermore data from ISRs could be assimilated for science studies. The example was given that ISRs provide the drift velocities at the magnetic equator.

What is the most difficult part in data assimilation? Some controversy come up whether the most difficult part in data assimilation is the "quality control of the data including the estimation of the data errors" or the "update of the error covariance in the data assimilation model". No clear answer was obtained for this question. Instead the discussion drifted towards the question of "how many ensemble runs are needed in an ensemble Kalman filter?" The answers drifted from 10 to the number of state vector members.

Can one obtain physical insight from a data assimilation model? The answer to this question was "yes" with the example of the more than 100 publications using the AMIE procedure.

Do you need a physical model in a data assimilation model? Some controversy about the need of a physical model came up. In this context it was discussed whether tomography could be considered data assimilation. No clear answer was found.

As a result of the panel discussion no definition of the term data assimilation could be agreed upon, although it was noted that it might be useful to have a definition for fair proposal and paper evaluations.

After the workshop, through Email, the following working definition of "Data Assimilation" based on http://en.wikipedia.org/wiki/ was agreed upon by the panel:

Data assimilation is a method in which observations of the current (and possibly, past) state of a system are combined with the results from a mathematical simulation model to produce an analysis, which is considered as 'the best' estimate of the current state of the system.

(Zia, 50) Applications of the Consortium of Resonance and Rayleigh Lidars to CEDAR Science, with conveners Jeffrey Thayer (University of Colorado, jeffrey.thayer@colorado.edu), Xinzhao Chu (U CO), David Fritts (NWRA/CoRA), Chiao-Yao (Joe) She (Colorado State University), and Gary Swenson (University of Illinois)

The workshop was held to introduce the concept of a lidar consortium and to discuss how this organization of lidar systems, people, and technology can benefit the CEDAR science community. Jeff Thayer gave the first talk describing the impetus for the lidar consortium. Bob Robinson from NSF provided perspective on how this effort relates to upper atmospheric facilities and the expectations involved. Discussion of the concept was open and clarification was requested on why only the Na wind/temperature systems made up the consortium. This important question was addressed by illustrating these systems' measurements are in greatest demand by the science community and, therefore, must be maintained and technology must be developed to keep them producing robust, high fidelity data. It was also demonstrated that these lidars are located at high, middle and low latitudes, thus contributing to the broad range of science topics. Furthermore, two of the other four existing US lidar programs are supported by Upper Atmospheric Facilities, the Arecibo broadband and narrowband resonance systems and the broadband and Rayleigh systems in Sondrestrom Greenland, and have a built-in support infrastructure. It is planned as the consortium evolves that these and the other lidar systems (the broadband Rayleigh system at Utah State University and the broadband resonance and Rayleigh system at the University of Alaska) will join or participate in consortium activities. The guest investigator program was also discussed and was called out as a program that should not be cut from the lidar consortium budget. Talks from the three Na wind/temperature lidar groups (Colorado State University representing the CSU lidar system, Colorado Research Associates representing the WEBER lidar at ALOMAR, Norway, and the University of Illinois representing the Maui lidar) were then given by Chiao-Yao She, Dave Fritts, and Gary Swenson respectively to discuss status and how they will function collaboratively under the consortium to serve CEDAR community better.

Following the descriptions of the three existing lidars, Xinzhao Chu (University of Colorado) introduced a new concept, i.e., the Consortium Technology Center (CTC). The CTC will be built for the CEDAR community. The primary responsibilities of the CTC are to advance, consolidate and lead lidar technology development; to provide technical support and ensure robust and high-quality measurements of CRRL lidars; to share lidar and optical technologies within and outside CRRL; and to establish a lidar school for the community to educate and train next-generation lidar researchers. The ultimate goal of the CTC is to establish a community center of excellence of lidar technology for advancing CEDAR science. A question was raised, concerning how the CTC will improve lidar development over individual PI lidar development. A few examples were presented by Xinzhao Chu to answer this question. First, the development of a mobile Doppler lidar for global wind and temperature measurements needs contributions from the whole community. As a team consisting of the CTC and CRRL, we are much stronger in lidar technology advancement. Second, the CTC will retain and continue wind and temperature lidar technology expertise, which will ensure the continuity of lidar technology in each individual lidar group in case of key personnel change. The CTC will also work to improve technology transfer to various lidar groups, enable other research groups to develop lidar capabilities without specific in-house expertise, and more rapidly advance the development.

Science campaign talks were introduced by Murry Salby and Richard Collins. Murry Salby described a lidar campaign that combined the US lidar assets with those of the European lidar community to study Kelvin waves at middle latitudes. Richard Collins introduced the thermospheric lidar concept and the need to develop a campaign centered on lidar resonance measurements from aurorally excited nitrogen ions.

19:30-21:30 PM3

(Zia, 50) Jicamarca Amigos, with conveners David Hysell (Cornell University, dlh37@cornell.edu) and Jorge (Koki) Chau (Jicamarca Radio Observatory)

The theme of this year's Jicamarca workshop was low-latitude research opportunities created by new instrumentation, radar modes, and models. Geoff Crowley plans to deploy a multistatic HF sounder in Peru to detect large- and medium-scale TIDs propagating in the vicinity of Jicamarca. This project is timely in view of the emphasis of precursor or seed waves in understanding day-to-day variability in equatorial spread F and will likely contribute to the C/NOFS science mission. Recent upgrades to the Arequipa Fabry Perot interferometer permitted the first successful wind and temperature comparisons with Jicamarca, with results presented by Micheal Favre. This facilitates renewed work on energy balance and dynamo efficiency problems.

The new full-profile incoherent scatter analysis technique being refined by Fabiano Rodrigues promises to substantially improve Jicamarca's topside capabilities. Upgrades to Jicamarca's data acquisition system, including the installation of digital receivers, have improved data quality generally and made possible refined aspect angle sensitivity measurements in the electrojet, as were presented by Don Farley. Likewise, Ron Woodman presented results from a series of demanding and sensitive experiments (synchrotron radiation, high-resolution tropospheric measurements, and solar flare effects measurements) made possible by numerous upgrades and facility improvements. Several institutional and programmatic improvements were also described by Jorge Chau and also by Wes Swartz, who reported on the radar school recently held at the observatory.

New particle-in-cell numerical simulations of Farley Buneman waves described by Meers Oppenheim account for a number of previously unexplained characteristics of coherent scatter from the electrojet and may ultimately make it possible to infer temperature profiles from the E layer. Cassandra Fesen showed how lowering the bottom boundary of the NCAR TIME-GCM has made it possible to recover the midnight temperature maximum, long observed in FPI and satellite data but absent from models. The gap between experimental and theoretical/model results appears to be closing along a number of fronts.

The workshop concluded with a presentation made by Ronald Woodman on behalf of the Peruvian Geophysical Institute commemorating the retirement of Don Farley and his many years of service to the Institute, to Jicamarca, and to the aeronomy and radio physics communities. Ron's presentation included photographs of many of the pioneers of our field and of some difficult to recognize signal processing equipment from the early days of Jicamarca.

Thursday 22 June

09:30-11:30 AM2

(Anasazi, 38) Opportunities of Research in Aeronomy in Latin America, with conveners Diego Janches (NWRA/Colorado Research Associates, diego@cora.nwra.com) and Carlos Martinis (Boston University, martinis@bu.edu)

This workshop was organized with the goal of describing existing, planned and foster research opportunities in Aeronomy in Latin America. The first part of the workshop was focused on topics of relevance in the region: the comparison of radar measurements from Jicamarca and Sao Luis (D.Hysell); the significance of gravity-wave energy deposition in Southern Patagonia (D.Fritts); the description of Brazilian campaigns related to sprites( F. Sao Sabbas) and gravity wave interactions with the ionosphere (D. Pautet).

The focus of the second part was the importance of conjugate studies in the region. It started with a summary of a recent workshop on the installation of an Upper Atmospheric Facility at the magnetic conjugate point of Arecibo, in Argentina (D. Janches). Then, results obtained from almost conjugate all-sky imagers located at Arecibo and El Leoncito showed the occurrence of simultaneous thermospheric and ionospheric processes in both hemispheres (C. Martinis). The importance of measuring the conjugate ionosphere of Arecibo was also discussed as well as the potential installation of an ionospheric facility near the conjugate point that would help to understand the electrodynamics of Arecibo (J. Meriwether). This presentation was followed by the description of an experiment consisting in the installation of all-sky imagers and GPS receivers at conjugate locations in the western part of South America (J. Makela). Finally, the status of the installation of several dynasondes located at conjugate sites that will allow the simultaneous sampling of E and F region ionospheric parameters was also presented (C.Valladares).

A brief summary of each presentation is given below.

• Dave Fritts (CORA) described the need for studies of the neutral atmosphere in Patagonia Southern Argentina. This geographic region seems to be one of the most Gravity Wave-driven active regions in the planet
• Dave Hysell (Cornell University) spoke about research opportunities combining the imaging radars at Jicamarca, Peru and at Sao Luis, Brazil. The new Brazilian imaging data should help in establishing irregularity drifts at the altitudes most responsible for scintillations and for identifying morphological characteristics (dominant wavelengths) for comparison with imager data.
• Dominique Pautet (Utha State University) focused on results of gravity wave interactions with the ionosphere, topic of a 2005 campaign, a collaboration between D. Fritts LWS NASA proposal and the Brazilian FAPESP DEELUMINOS proposal.
• Fernanda Sao Sabbas (INPE) presented a summary of Aeronomy facilities of the Brazilian National Institute for Space Research, INPE. She described the four year Sprite and Transient Luminous Events project DEELUMINOS and gave preliminary results of the first sprite campaign performed in Brazil and stressed how international collaboration can contribute to develop new science in South America.
• Diego Janches (CORA) gave a summary of the recent workshop held at Arecibo focused on developing an Upper atmospheric facility at the Arecibo Magnetic Conjugate point located near the coast of Argentina
• Jonathan Makela (University of Illinois) described a new experiment that will begin in Fall `06 with dual imagers and GPS scintillation equipment at conjugate locations in Chile and Colombia, observing the same set of magnetic flux tubes that pass over Jicamarca. From the two sites it will be possible to study the role that the local ionosphere plays in the development and characteristics of scintillations.
• Carlos Martinis (Boston University) presented results of conjugate observations of ionospheric and thermospheric processes using all-sky imagers at Arecibo and El Leoncito, Argentina, with supporting information from GPS phase fluctuations measurements. He stressed the need to continue these types of observations and the need to model how mid-latitude processes reach into low-latitudes and vice versa.
• John Meriwether (Clemson University) talked about the importance of the conjugate point on the local electrodynamics of Arecibo. Several questions were posted: how can the current be conserved given that there is a divergence in the zonal current?, are the F-region heights at both hemispheres anticorrelated?. Thus, to understand the driving forces that underlie plasma height variations of the Arecibo ionosphere is necessary to measure the neutral and plasma properties of both the local and conjugate hemispheres.
• Cesar Valladares (Boston College) gave an update of the installation of five dynasondes in South America. He indicated that all five sites have been visited and local scientists and engineers are very enthusiastic about this project. He also explained the importance of measuring the E region at Leticia (~8 N mag lat) and Carmen Alto (~8 S mag lat) for the forecasting of the onset of ESF.

(Sunset, 73) Thermospheric Density and Composition, with convener Arthur Richmond (National Center for Atmospheric Research, richmond@ucar.edu)

The density and composition of the thermosphere are strongly dependent on variations in solar XUV radiation, on high-latitude Joule heating, on thermospheric dynamics, and on dynamical, chemical, and radiative coupling with the lower atmosphere. This workshop presented to the CEDAR community the NASA Living With a Star coordinated research project on thermospheric density and composition, which has an objective of improving the modeling of satellite drag and of ionospheric effects. This three-year project started in 2005, and is composed of sub-projects headed by Principal Investigators Phil Anderson, Geoff Crowley, Doug Drob, Dirk Lummerzheim, Art Richmond, Stan Solomon, and Kent Tobiska. Each PI gave an overview of his sub-project, except that Anderson's project was very ably presented by his student Bob Johnston. Additional presentations on this topic were made by Young-Sil Kwak, Dave Pawlowski, Yue Deng, and Yongliang Zhang.

The integrated research program has six main goals:

1. improve quantitative models of solar inputs to the thermosphere;
2. improve quantitative models of magnetospheric inputs to the thermosphere;
3. improve first-principles global models of the thermosphere;
4. analyze thermospheric responses to solar and magnetospheric inputs on time scales from minutes to the solar cycle;
5. improve the NRLHWM empirical model of thermospheric winds; and
6. make research products available to the community.

The main research products will be:

1. an improved solar EUV/X-ray irradiance model;
2. improved calculation of solar energy deposition;
3. an empirical model of high-latitude Poynting flux:
4. an empirical model of subauroral electric fields;
5. an improved empirical horizontal wind model;
6. parameterizations of sub-grid-scale auroral processes for thermospheric general-circulation models; and
7. publications on the above, and on analyses of thermospheric responses to solar and magnetospheric inputs.

Kent Tobiska is improving the S2K model of solar spectral extreme-ultraviolet and X-ray irradiance to include high spectral resolution and a high-time-resolution solar-flare component.

Stan Solomon has developed an improved parameterization of solar energy deposition in the thermosphere, and is evaluating the thermospheric response by comparing physical-model predictions with observations of satellite drag.

Art Richmond is leading the development of an empirical model of magnetospheric energy inputs to the thermosphere, and the modeling of the thermospheric response to these inputs on large and small scales.

Phil Anderson (represented by Bob Johnston) is developing an empirical model of strong subauroral electric fields, spatially related to the lower-latitude boundary of auroral particle precipitation, that occur during disturbed periods. With collaborators, he will also examine the thermospheric response to these fields.

Dirk Lummerzheim is leading a modeling study of heating and mixing of thermospheric constituents in small scale aurora, including the effects of ion outflow. The model can be sampled along simulated spacecraft trajectories.

Geoff Crowley is modeling the thermospheric response to solar and magnetospheric energy inputs with a thermospheric general-circulation model, and is comparing the model predictions with observations of satellite drag.

Doug Drob is updating the NRL Horizontal Wind Model, using a much larger data base than was used in the original model, with the inclusion of many more data below 200 km.

Postdoc Young-Sil Kwak is analyzing the forcing of high-latitude thermospheric winds with a thermospheric general-circulation model.

Student Dave Pawlowski has analyzed the thermospheric response to solar and magnetospheric forcing using a one-dimensional version of a thermospheric dynamics model, comparing results for different model inputs.

Recent Ph.D. Yue Deng has used a new thermospheric dynamics model to simulate the thermospheric response to the 2003 Halloween storm, showing that the predicted response varies considerably depending on the model of high-latitude electric potential that is used.

Yongliang Zhang and collaborators have simulated the thermospheric composition response to magnetospheric energy inputs using a coupled thermosphere-ionosphere-magnetosphere model. Comparison with observed O/N2 ratios indicates that the present version of the model may overestimate Joule heating.

On the whole, the presentations demonstrated that, although first-principles models with recently improved parameterizations are able to reproduce climatological thermospheric variations reasonably well, the simulated response to magnetospheric inputs for particular events depends significantly on uncertainties in the magnitude of the inputs. Progress in the coordinated LWS research project and in related CEDAR research are expected to improve our ability to model the thermosphere more accurately under a broader range of conditions.

(Zia, 65) MLT Structure and Dynamics in Tropical/sub-tropical Regions, with conveners Xinzhao Chu (University of Colorado, xinzhao.cu@colorado.edu), Jonathan Friedman (Arecibo Observatory), and Gary Swenson (University of Illinois)

Recent analyses of lidar-measured MLT (mesosphere and lower thermosphere) temperatures at Maui (20.7N, 156.3W) and Arecibo (18.35N, 66.75W) have shown significant differences between these two tropical/sub-tropical sites. The MLT over Maui experiences the low summer mesopause altitude (~86.5 km) that is observed at mid and high latitudes, while at Arecibo the summer transition does not occur. Maui and Arecibo are separated in longitude by 900, so these observations point to possible longitudinal effects. Such effects, if global, would be most noticeable at the transition region from mid to low latitude, such as represented by these sites. In an attempt to understand these differences, a workshop was called for at the 2006 CEDAR Workshop. This workshop brought together a wide spectrum of views of this atmospheric region that has been little studied and is poorly understood. Presentations were given on observational results still under study, and how tidal studies may contribute to understanding the low latitude MLT thermal structure and dynamics.

To open the workshop, Xinzhao Chu (CU) introduced the motivations described above. Jonathan Friedman (Arecibo) presented the observational results from Arecibo and Maui that prompted convening this workshop. Jeffrey Forbes (CU) followed with a tutorial presentation that cleared misconceptions on how modelers describe solar tides, and with a thorough description of the basics of tidal and wave modeling and their nomenclature. His talk also gave a basis for beginning to understand how tidal modulation may influence the differences observed in the MLT at disparate sites such as Maui and Arecibo. Many of the participants in the workshop praised Jeff's tutorial as providing the means to understand papers on tides and waves.

Elsayed Talaat (APL) presented SABER low-latitude temperature measurements and how he has developed a technique for extracting the diurnal tide from SABER-measured temperatures. This technique will be very useful in further analysis of the differences between Arecibo and Maui, as the lidar temperature observations are still made exclusively at night. There was agreement, though, on the necessity for full diurnal cycle measurements at the ground-based sites. Qian Wu (NCAR) presented multi-year TIDI neutral wind observations and compared them to TIME-GCM. A CEDAR student, Rubin Delgado (UPR), gave a presentation on metal layer chemistry and the status of its understanding at Arecibo.

Mike Taylor (USU) also presented a comparison, in this case between an all-sky temperature mapper at Maui and the Arecibo K Doppler lidar and discussed the influences of phenomena such as the Quasi-Biennial Oscillation (QBO) and Semi-Annual Oscillation (SAO). At the end Xinzhao Chu (CU) compared the semidiurnal tides between Maui and Arecibo, and pointed out the opposite phases in January between these two sites. Apparently, these interesting results call for further investigation of tropical MLT thermal structure and dynamics through the combination of lidar and satellite observations with atmospheric model simulations.

11:30-13:00 AM3

(Pinon, lunch provided, 23) Scheduling the Upper Atmospheric Facilities for World Day Coordinated Experiments, with convener Wesley Swartz (Chair of URSI Incoherent Scatter Working Group, Cornell University, wes@ece.cornell.edu)

Establishing "World Day" (WD) schedules to coordinate experiments at all the incoherent scatter radars and associated instrumentation is one of the activities of the URSI Incoherent Scatter Working Group (ISWG). The 23 attendees of this workshop finalized the schedule for 2007 which can now be found via the link: http://people.ece.cornell.edu/wes/URSI_ISWG/2007WDSchedule.htm.

This year proposals for the 2007 World Days were requested and sent to a number of anonymous reviewers for evaluation. The final schedule was based on the requirements stated in the proposals, the evaluations of the reviewers, and the discussion during the workshop. A number of the comments made during the workshop are worth repeating here followed by brief summaries of the experiments placed on the 2007 schedule. More details for each of these experiments are available on the web at the above link.

Summary of Attendee Comments
Since the major World Days often have specified seasonal requirements, the other synoptic World Days should be "dithered" over a 3 year period to make sure all seasons are adequately covered to maintain and extend the long-term synoptic data base. These synoptic runs can be shorter; 40 hours was thought to be a good compromise. The synoptic runs were placed on those "template" days not otherwise modified by the formally proposed days. Although the 30+ days on the schedule for 2007 is more than the typical 21-22 days in previous years, it was deemed not a problem for most of the facilities (the exception is Arecibo).

The start times for each World Day period were clarified and will officially be 1600 UT. If some sites need extra setup and warmup time, those sites must schedule sufficient preparation time so that the World Day data is actually being acquired by 1600 UT. The experiment ending date will no longer appear on the schedule as it was a point of confusion. Instead the duration will be listed. Although there was interest expressed in concentrating efforts on the solstices and one or both equinoxes, there was also general interest in running through the actual changes from one season to another. With constraints on the resources, the current mix of some longer runs with the scattered shorter runs was thought to be a good compromise.

Since the International Polar Year (IPY) will start March 1, 2007, the EISCAT Svalbard radar will commence running 24/7 for a full year. The other ISRs will start a 5 day World Day period on March 1 to coincide with the beginning of the IPY.

The new World Day proposal scheme seems to be on the right track, but some of the language may need to be modified to reflect the more global objectives of these experiments. A description of this proposal procedure can be found at http://people.ece.cornell.edu/wes/URSI_ISWG/RequestingWD.doc.

Although no proposal for the THEMIS project was submitted for the new formal review process, a presentation was made of the satellites' capabilities and need for ground based data. Some flexibility may be needed in the ISR schedules for acquiring coincident (high latitude) data with THEMIS once orbits become known.

Summary of 2007 World Days
The objectives major World Day periods are summarized here.

• Title: Dynamics and temperature of the lower thermosphere during sudden stratospheric warming with the objectives:
  • To measure neutral wind (zonal and meridional components) and electron and ion temperatures in the lower thermosphere before and during sudden stratospheric warming
  • To compare variations in temperature and winds to average variations observed by ISRs during the winter
  • To compare variations in temperatures and winds to mesospheric response as given by MF and meteor radars and lidars.
  • To extend studies of stratospheric warming effects to the lower thermosphere and investigate possible coupling with the ionosphere
  • To examine the mechanisms responsible for variations in lower thermospheric dynamics and temperatures and investigate to what degree they can be related to sudden stratospheric warming.
  • Contacts: Larisa P. Goncharenko, Irfan Azeem, and William Ward
• Title: ISR/GPS Coordinated Observation of Electron Density Variations with the objectives:
  • To study latitudinal variations of the ionosphere in the American longitude sector.
  • To examine time and latitudinal variations of electron content in the plasmasphere.
  • To test the GPS TEC mapping function.
  • Contacts: Shun-Rong Zhang and Anthea Coster
• Title: High-resolution study of weak coherent echoes from the equatorial D and E region using the MST-ISR with the objectives:
  • To measure with high time and spatial resolution radar reflectivities, winds and spectral widths from turbulent layers and other electron irregularities from 10-180 km.
  • To characterize the gravity wave and instability processes in the tropical mesosphere over Jicamarca.
  • To conduct a seasonal study by sampling days around both equinoxes and solstices and compare data with empirical or model climatology.
  • Contacts: Gerald Lehmacher, Erhan Kudeki, and Jorge Chau
• Title: Latitude Dependence of the F-Region Plasma Variations during the Passage of Large- and Medium-Scale Traveling Ionospheric Disturbances with the objectives:
  • To measure with high time resolution the density profiles and ion drift velocity during the generation and propagation of large- and/or medium scale traveling ionospheric disturbances (TID).
  • To clarify generation and propagation mechanisms of large- and medium-scale TIDs using the ISR measurements and horizontal two-dimensional observations using GPS networks and all-sky imagers.
  • Contacts: Takuya Tsugawa, Shun-Rong Zhang, Anthea Coster, Kazuo Shiokawa, and Yuichi Otsuka
• Synoptic
  • Synoptic experiments are intended to emphasize wide coverage of the F-region, with some augmented coverage of the topside or E-region to fill in areas of the databases that have relatively little data.
  • Contact: Wes Swartz

13:00-16:00 PM1

(Anasazi South to 16:00, 24) Meteors and the Upper Atmosphere, with conveners Lars Dyrud (Center for Remote Sensing, ldyrud@cfrsi.com) and Diego Janches (NWRA/CoRA)

The workshop was held in a short presentation style followed by discussions. We had 11 presentations in the 3 hour session, 5 of which were student presentations. The agenda left room for discussion which was interspersed among the presentations. The speakers were, Lars Dyrud of CRS, Sigrid Close from LANL, Jorge Chau from Jicamarca Radio Observatory, Meers Oppenheim from Boston University; Jonathan Fentzke, Chunmei Kang, Elias Lau, Santiago de la Pena from University of Colorado, Diego Janches from CoRA/NWRA; and Stan Briscinski and John Mathews from Penn State University. The speakers and the topics discussed reflected the multi-disciplinary nature of this field. Topics included the meteor deposition of metal layers, modeling of meteor trail and head echoes, modeling of the global meteoric mass flux, observation using ISR radars and satellites and a novel meteor radar calibration method. All these subjects showed, once again, the growing interest by the community in the effects and understanding of meteors and the mesopause. The talks specifically demonstrated a growing consensus, at least among CEDAR researchers, that the sources of small, dust size meteors are unaccounted for in earlier studies and existing characterizations of the meteor flux. These dust size meteors are the dominant ISR meteor observation. Finally, the conveners, Diego Janches and Lars Dyrud would like to thank everyone who took part and attended this year's workshop.

(Anasazi North to 16:00, 40) Incoherent Scatter Radar Long-Duration Experiments and CEDAR, with conveners Shunron Zhang (MIT Haystack Observatory, shunrong@haystack.mit.edu) and Larissa Goncharenko (MIT Haystack Observatory)

A number of long-duration Incoherent Scatter Radar (ISR) experiments have been run in response to community requests. These experiments, including

• October 4 - November 4, 2002 (Millstone Hill and ESR)
• May - June, 2004 (1000-hour run at ESR)
• September 1-31, 2005 (ISR World Month)
• March 6- April 6, 2006 (ISR World Month)

The workshop combined short observatory reports and longer specific science talks. They were presented after an introduction by Shunrong Zhang, from MIT Haystack Observatory, who highlighted the scientific questions intended to be addressed by the experiments, including I-T coupling studies, space weather monitoring, and modeling and data assimilation, and gave an overview of the experiments.

• Anja Stromme from the EISCAT society described all 4 long-duration runs by the Svalbard radar and the Tromso radar, and sample results of the data and the science that can be addressed with the EISCAT data. She also discussed long-duration runs in the future including during the IPY.
• Criag Heinselman, from Sondrestrom Facility of SRI, described the modes of observations for two latest 30 day runs with impressive movies of the convection pattern and other ISR parameters changes, indicating large day-to-day variability.
• Larisa Goncharenko from MIT Haystack Observatory, when describing the data status of Millstone Hill 30-day runs, reported that data from all the three runs were calibrated and are in their final version in the databases (MADRIGAL and CEDAR). She presented 4 research topics being pursed, including lower thermospheric dynamics, ionospheric positive storms studies, solar flare effects, and F-region day-to-day variability.
• Michael Sulzer from Arecibo Observatory and Michael Nicolls from Cornell University described the Arecibo radar's plasma line experiments during the March - April, 2006 World Month. It was indicated that the plasma line asymmetry allowed for independent electron temperature determination and could result in new science associated with the molecular ions and low atmospheric monitoring with nice continuity over the atom-molecule ions transition region.
• Koki Chau from the Jicamarca Observatory described the 2005 and 2006 World Month experiments at Jicamarca. Sample results from various observational modes were shown.
• Mamoru Yamamoto of Kyoto University which owns the MU radar provided slides with information about modes of ionospheric observations with MU, along with descriptions on the recent development of the MU radar ground.
• Masha Kuznetsova of NASA GSFC reported the CCMC support of the ISR World Days, and showed the model system at CCMS as well as results from USU GAIM outputs for the 2005 World Month.

The presentation of Frank Lind of MIT Haystack Observatory, given by Phil Erickson, addressed a new type of ISR for continuous space weather monitoring. This mid-size radar features full automation, always-on, real-time data delivery among others. A prototype at Millstone Hill, the Zenith Incoherent Profiler (ZIP) was discussed.

Science emphasis have been on the lower thermospheric dynamics, ionospheric oscillations and variability, and modeling aspects.

• Cassandra Fesen of Dartmouth College presented theoretical results during the ISR 30-day run in October 2002 obtained with the TIME-GCM year-long simulation. She focused on height variations of different tidal components of neutral winds and temperature and demonstrated their large day-to-day variability over the 30-day period. She highlighted a few challenging questions that need to be addressed.
• Jeff Forbes of University of Colorado discussed quasi-2-day wave effects in the mesosphere, thermosphere and ionosphere systems by showing examples of various prior studies. He pointed out that opportunities exist to elucidate a number of upper atmospheric processes, through combined space-based and ground-based observations & modeling/theory.
• Luke Moore of Boston University discussed day-to-day variability of the ionospheric E-layer based on Millstone Hill and Svalbard observations in the 2002 long-duration run and on a theoretical ionospheric photochemical model. Solar flux was found to be dominant source of variability, and the change in solar declination the secondary source at Millstone Hill but dominant at Svalbard.
• Shunrong Zhang presented a study of the ionospheric variability using 3 of the 30-day run data from Millstone Hill. With focus on the height variation of various changes, he noted the maximum of quiet-time midday variability in Ti and the minimum in Ne in 120-130 km heights. He noted also the oscillation in Ti at 125 km. He indicated very pronounced height changes of ionospheric responses to solar and magnetic activities.
• Wenbin Wang of NCAR HAO simulated the 2002 30-day experiments at Millstone Hill using NCAR-TIMEGCM. He noted, based on six cases of test runs with different combinations of F107, Ap and NCEP values controls on the model, changes of the spectral peaks of various periodicities. He indicated the 2-3 day periodicity accompanying the magnetic activity, and the 5 day periodicity not as a result of magnetic activity and solar activity forcing.
• Jan Sojka of Utah State University summarized modeling studies of the ionospheric weather and climatology with USU ionospheric models using month-long ISR experiments. He noted neutral wind and ionospheric dynamic effects on the ionospheric sunrise and variability for high latitude and subauroral/mid-latitudes. He also reported solar flare effects.
• Don Thompson of Utah State University talked about using the USU Gauss-Markov Kalman Filter to study the topside ionosphere. He discussed GMKF validation efforts and outlined plans for future work, including simulations of the ISR 30-day run periods to study the topside ionosphere over North America.
• Scott Palo of University of Colorado presented analysis of planetary wave activity in MF radar data and TIMED SABER data in April 2002 showing 6.5, 9 and 16-17 day waves and discussed how planetary wave activity affects tidal characteristics in the lower thermosphere and mesosphere. He also presented evidence of 2-day and 4-day waves in SABER and TIDI data and TIME-GCM simulations showing 2-day wave impact on ionosphere.
• Larry Paxton of JHU Applied Physics Lab presented overview of GUVI data for the September 2005 and March 2006 periods. He highlighted possibilities of joint studies of ionospheric and thermospheric parameters during isolated storms in March 2006 and large quiet time variability in O/N2 data. He also noted variations in separation of equatorial arcs during quiet time and the lack of understanding of mechanisms driving these variations.

(Sunset to 16:00, 28) Plasma Structures and Turbulence (PSAT), with conveners Evgeny Mishin (Boston College, evgenii.mishin@hanscom.af.mil) and Anatoly Streltsov (Naval Research Laboratory, anatoly.streltsov@nrl.navy.mil)

The workshop was held to address CEDAR science interests in the effects of plasma instabilities and nonlinear wave processes/structures in the ionosphere. Presentations included recent results of theoretical, numerical, and experimental studies of various wave phenomena occurring in the ionospheric plasma.

R. Cosgrove and R. Doe discussed how AMISR's multi-beam capability can be used to identify the ionospheric Alfven resonator (IAR) signature. A. Streltsov presented the results from a numerical study of the generation of small-scale density structures in the topside ionosphere by intense, nonlinear Alfven waves caused by the feedback instability inside the IAR in the downward current region. G. Milikh showed that the enhanced electron density, observed by the Sondrestrom ISR in the stormtime auroral electrojet region void of electron precipitation, is in good agreement with the anomalous heating due to the Farley-Buneman instability. E. Mishin presented electromagnetic and plasma disturbances in stormtime subauroral ionosphere from the CRRES and DMSP satellites, indicating the dominant role of various unstable processes in the ring current-plasmasphere overlap. R. Greenwald's presentation aimed at showing that the source for decameter-scale irregularities, routinely observed by the SuperDARN radars, is the temperature gradient instability on plasmapause field lines. P. Guzdar and N. Gondarenko showed numerically how a combination of the gradient drift and Kelvin Helmholtz instabilities forms structuring of high-latitude plasma patches via the sequence of developing secondary instabilities. D. Hysell presented the latest radar images of equatorial spread F at Jicamarca, as well as the results of numerical simulation of the fully-developed turbulence, where secondary instabilities form all over the place, partly resembling that in the polar patches. Yue Deng concluded the session showing the GITM results demonstrating the effect of a vertical circulation on the electron density altitude distribution, which has been proposed to help understand the source of the tongue of ionization.

Overall, the presentations show the importance of plasma instabilities and nonlinear processes for ionosphere-magnetosphere coupling.

(Zia to 16:00, 36) Recent Progress in Fabry-Perot Applications to CEDAR Science, with conveners John Meriwether (Clemson University, john.meriwether@ces.clemson.edu) and Rick Niciejewski (University of Michigan)

About 50 people attended the "Recent Progress in Fabry-Perot Applications to CEDAR Science" workshop Thursday afternoon, June 22 2006. This enthusiastic response resulted in the workshop extending from 1:00 to 4:00 pm.

The last FPI workshop was held at Longmont CO in 2002. Since that time, new observatories, new instruments, and new science issues have surfaced. The TIDI instrument on the TIMED satellite has proved successful in making interesting science contributions. The goals of the current workshop focused on sharing these results and updating the community on research efforts bearing on these instruments.

Rick Niciejewski presented an operations update for the TIDI instrument. TIDI has been making routine synoptic observations of the mesosphere and lower thermosphere since February 2002 providing a wealth of new dynamics measurements. The instrument continues to perform well with a duty cycle near 100%. In addition to horizontal wind measurements, the TIDI instrument can now derive the ozone volume mixing ratio during daylight conditions in the MLT.

A University of Michigan team (led by Dr. R. Niciejewski) is constructing a chain of 3 FPI instruments at low latitudes across South America and Ascension Island with the goal of improving our understanding of the onset characteristics of equatorial spread-F conditions. It has been theorized that the magnitude and sign of the early dusk neutral wind in the upper thermosphere controls the seeding of spread-F and low latitude scintillation events. This chain will characterize the neutral wind during such conditions to better understand the longitudinal extent.

Modeling of the dynamics of the upper thermosphere can benefit from the synergy associated with correlative atmospheric sampling. Dr. Aaron Ridley (U. of Michigan) described a variable grid model of the upper atmosphere and the usage of such a model with both satellite observations and ground based sampling.

Alternatives to remote sampling of the thermosphere to directly measure the neutral wind are few. One successful approach presented by Dr. Doug Drob (Naval Research Laboratory) is an infrasound technique that employs low frequency sound waves induced at ground level or in the lower atmosphere and carefully records the strength and azimuth deviations of ray paths. The atmosphere and its temperature gradients act as a waveguide permitting infrasonic waves to propagate over vast distances, and careful modeling allows the retrieval of high altitude winds.

The optical facility at the Arecibo observatory has undergone an upgrade in its Balmer H-alpha FPI in which the photomultiplier detector was replaced by the Andor CCD camera. Observations of Balmer H-alpha provide a measure of the neutral hydrogen abundance in the exosphere, but the observational technique is difficult and at the limit of technology. Dr. John Noto (Scientific Solutions, Inc.) described the upgrades to the Balmer FPI at Arecibo and presented details regarding the data analysis procedures.

Another technological challenge is the observation of daytime airglow from ground level. Dr. Steve Watchorn (SSI) described recent efforts at constructing a triple etalon FPI. This instrument was first field-tested at the Gukana Observatory in Alaska and then installed at the CTIO observatory in the Chilean Andes. When completed, the instrument would begin an effort to observe upper thermospheric winds during the day.

The University of Wisconsin maintains a Balmer H-alpha FPI at its Pine Bluff Observatory. Dr. Susan Nossal (University of Wisconsin) described research efforts that have achieved a long term series of neutral hydrogen measurements of the exosphere dating back to 1977.

Dr. Ed Mierkiewicz (University of Wisconsin) described the capabilities of the Spatial Heterodyne Spectroscopy (SHS) technique pioneered by the University of Wisconsin. The instrument resembles a traditional Michelson interferometer but with gratings replacing the two reflective mirrors. The instrument is ideal for measuring weak emissions such as OII (3727Å).

New results obtained by the FPI operated at Arequipa Peru obtained after the replacement of the photomultiplier with a CCD camera were described by Dr. Michael Faivre (Clemson University). The improved capabilities of this instrument in measuring winds and temperatures in the upper thermosphere were applied to the acquisition of measurements of the neutral wind field flow patterns by employing an 8 position wind mapping scheme. Application of this instrument to obtain improved measurements with a high temporal resolution (but only 4 directions) found significant indications of thermospheric waves in the thermosphere in both the temperature and wind data. The fluctuations observed were of the order of 5 to 15 m/s and 20 to 75 K with periodicities of 45 to 120 minutes.

Dr. John Meriwether described the details of the analysis of MiniME measurements of thermospheric winds and temperatures. MiniME is a miniaturized FPI that has been applied to thermospheric dynamics observations. The prototype instrument has operated at Arecibo for one year and will be installed in central Alaska during the fall of 2006.

Dr. Jon Makela (University of Illinois) described plans for the installation of a bi-static FPI system for Cape Verde located near the Western African coastline close to the magnetic equator. Two MiniME instruments placed on two islands separated by ~300 km would perform these measurements. The deployment date is expected to be the summer or fall of 2007.

19:30-21:30 PM3

(Zia, 20) Radar Meteor Studies: Where Next? with conveners John Mathews (Pennsylvania State University, jdmathews@psu.edu), Sigrid Close (Los Alamos National Laboratories) and Lars Dyrud (Center for Remote Sensing)

Description: Large-aperture radar study of meteors has matured greatly in the approximate decade since the first observational results were being reported. However, many questions remain including the radio science and plasma instability issues implicit to the head-echo and range-spread trail echo scattering mechanisms and the possible influence of meteor-trails on E-region electrodynamics. The purpose of this workshop is to discuss how to approach these issues observationally and the likely need for new radar capabilities.

Report: Approximately twenty attended this session that was dedicated to discussion of new approaches to meteor observations given the maturity of the current generation of observations. An immediate consensus emerged that multi-frequency, multi-look angle, common-volume radar observations are needed to solve the numerous radio science and plasma physics questions. More observations at ALTAIR are considered necessary as it allows two-frequency observations of head/trail-echoes. David Hysell will be installing a 30 MHz radar on Saint Croix that will look over Arecibo Observatory and that plus a modernization of the on-dish VHF radar would provide a major new capability. Additional ideas included ultra bandwidth pulsed radars creating meteor "ionosondes" and utilization of passive radar techniques-especially in combination with existing radars-to achieve the desired frequency/look-angle diversity. The latter would surmount the difficulties of FCC limitations on transmit frequencies at current observatories. Other discussion centered on the minor biases that have emerged in the current large-aperture V/UHF radar studies.

Friday 23 June

09:30-11:30 AM2

(Anasazi South, 68) Penetration Electric Fields and Ionospheric Storms, with conveners Chaosong Huang (MIT Haystack Observatory, cshuang@haystack.mit.edu) and Stanislav Sazykin (Rice University, sazykin@rice.edu)

The Penetration Electric Fields and Ionospheric Storms workshop was held on Friday, 23 June 2006 in the Anasazi South Room. This workshop focused on penetration of the interplanetary electric field to the low-latitude ionosphere and ionospheric storms. Electric field penetration has been studied for many years. However, a number of outstanding problems remain unsolved. These problems include how long the penetration electric field can exist, how much of the interplanetary electric field can reach the equatorial ionosphere, how significantly the penetration electric field will affect the redistribution of the storm-time global ionospheric plasma, and how the penetration electric field effect can be separated from wind disturbance dynamo effect. The speakers of the workshop presented the latest observational and simulation results related to these problems.

John Foster (MIT) began the workshop with a presentation of localized stormtime enhancement of total electron content (TEC) at low latitudes in the American sector. It is often observed that the ionospheric plasma density and TEC are significantly enhanced over Florida in the dusk sector during intense magnetic storms, which is termed the storm enhanced density. The TEC enhancement poleward of the equatorial anomaly forms as equatorial TEC decreases near dusk. An important phenomenon reported in this talk is the similar evolution of TEC enhancements in conjugate hemispheres. Many large storms have a repeatable signature. The TEC enhancements over the Caribbean and the conjugate region in eastern Brazil have been observed in a number of storm cases.

Tim Fuller-Rowell (NOAA) reported the recent progress of storm-time ionospheric electrodynamics and neutral wind disturbance dynamo simulated with the Coupled Thermosphere Ionosphere Plasmasphere Electrodynamics (CTIPe) Model. The detailed results of the 31 March 2001 storm were presented. The penetration electric field may dominate over neutral disturbance dynamo within the first hours of the storm. Dayside disturbance dynamo reduces upward drift, and the nightside disturbance dynamo reduces downward or reverses to upward drift. Disturbance dynamo can reduce or increase pre-reversal enhancement of the equatorial ionospheric upward drift and persists for at least 24 hours.

Michael Kelley (Cornell U.) first gave a brief review of observations and mechanisms of penetration electric fields. He then focused on the IMF By-dependent equatorial ionospheric electric fields associated with closure of solar wind/Earth-currents perpendicular to the ecliptic plane. The electric field observations during the 31 March 2001 storm were analyzed in detail. In this case, a number of large, short-lived enhancements of the equatorial ionospheric electric fields are well correlated with the sudden changes in the IMF By. The relationship between the magnetospheric- ionospheric current system and By-related penetration electric fields were discussed.

Aaron Ridley (U. Michigan) used the AMIE results to drive global ionosphere-thermosphere models as well as inner magnetosphere models in the calculations of penetration electric fields during magnetic storms. The purpose of the work is to develop a model that can provide a global picture of the electric field. Two storm cases on 4 May 1998 and 15 July 2000 were examined. It was found that the largest penetration electric fields during a storm are due to the divergence of the penetration electric field related to subauroral polarization stream (SAPS). The large penetration electric field is primarily on the dusk sector but extends down to the equator during strong driving. The dayside penetration electric fields are relatively weak because they were overwhelmed by the high latitude and SAPS fields.

Chaosong Huang (MIT) presented the statistical result of the efficiency of the penetration electric field. The efficiency is defined as the ratio of the change of the equatorial ionospheric electric field to the change of the interplanetary electric field. They searched the Jicamarca radar data over five years (2001-2005) and identified more than 70 clear cases of penetration electric fields. It is found that the interplanetary electric field can penetrate to low-latitude ionosphere for several hours without effective shielding during continuous southward IMF and that the efficiency of the penetration electric field is ~10%. This efficiency is valid for both short (<1 hour) and long duration (several hours). The statistical result of the penetration efficiency is in very good agreement with the recent theoretical result (11.9%) of William Burke.

Stan Sazykin (Rice University) presented, on behalf of Joe Huba (NRL), a report on the self-consistent modeling of the coupled ionosphere-magnetosphere system with the coupled SAMI3- RCM numerical model. The ionospheric part (SAMI3) of the coupled model has been recently extended from the region of closed magnetic field lines to the whole ionosphere including the high-latitude part. Simulations of idealized cases of prompt penetration with the newly-extended model show consistent increases in the vertical TEC in the afternoon-to-dusk regions of Appleton anomaly, and corresponding depletions in the equatorial ionosphere, in response to sudden southward turnings. In another development, SAMI3 was driven by a high-latitude time-dependent convection electric field obtained from the global MHD Lyon-Fedder-Mobary (LFM) numerical model. Initial results indicate that SAMI3 shows formation of a cross-polar-cap tongue of ionization.

Ray Greenwald (JHU/APL) presented the observations of high-latitude electric field penetration to the subauroral ionosphere with the SuperDARN HF radars. Electric field penetration during quiet times and during modest activity was discussed. It is shown that electric fields in the M-I system are determined by dynamos or processes such as gradient and curvature drifts that produce charge separation. Winds are the relevant ionospheric dynamos in the Earth-based reference frame. Magnetospheric circulation produces the electric fields at high-latitudes, probably down to the ionospheric projection of the plasmapause. The equatorward boundary of the ionospheric trough and/or the ionospheric projection of the plasmapause might be a good demarcation between magnetospherically controlled convection and ionospherically controlled convection. Transient (10-30 minute) penetration of high-latitude electric fields to lower latitudes can occur as a consequence of undershielding and overshielding.

Dave Anderson (NOAA) discussed the relationship between the interplanetary electric fields to observed low latitude electric fields. The interplanetary electric field is calculated from the ACE observations. The equatorial ionospheric zonal electric fields are derived from the DH-inferred ExB drifts at different longitudes in the Peruvian, Philippine and Indian sectors under geomagnetically quiet and disturbed conditions. It is shown that the electric fields derived from ground magnetometers are in reasonable agreement with radar measurements. The penetration electric field derived from magnetometer measurements is about 10% of the interplanetary electric field, consistent with the statistical result of Chaosong Huang.

Tony Manucci (JPL/NASA), on behalf of Bruce Tsurutani (JPL/NASA), discussed the daytime superfountain of the equatorial ionosphere related with penetration electric fields during intense geomagnetic storms. The primary effect of storm-time penetration electric fields is to create stronger equatorial ionization anomaly and to broaden/spread anomaly peaks, resulting in significant TEC increases at the anomaly latitudes. For example, very large (400%) TEC increases are observed in the dayside midlatitude ionosphere ( 30° MLAT) within the first few hours after the impingement of strongly southward interplanetary magnetic field onto the magnetosphere for several intense storm cases. Penetrating electric fields of 3 to 5 mV/m are the cause of the enhanced equatorial anomaly, and the midlatitude TEC excesses are due to the dayside fountain effect. The physical implications and persistent ionospheric effects of storm-time penetration electric fields have not been well understood, and further investigations are required.

Trevor Garner (UT Austin) presented the simulation results of the effects of the magnetospheric drivers on the penetration electric field with the Rice Convection Model (RCM). The RCM is used to calculate extended periods of strong penetration electric fields with realistic inputs. It is shown that the strength of the penetration electric field is sensitive to the pressure and temperature of the plasma sheet and the variability of the magnetic field. For example, when the pressure of the plasma sheet plasma is increased by a factor of 3, the shielding effect of the ring current is greatly weakened, and the magnetotail convection electric field penetrates into the inner magnetosphere for several hours without significant decay.

The last two speakers (Tony Mannucci and Trevor Garner) were scheduled to talk in this session. However, we ran out of time and had to terminate the session after the talk of Dave Anderson. Tim Fuller-Rowell kindly agreed for these two speakers to give their presentations in the session "Global Electrodynamics and Storm Effects at Middle and Low Latitudes" in Friday afternoon.

(Zia, 27) Climatology / Long-Term Trends, with conveners Jan Sojka (Utah State University, fasojka@gaim.cass.usu.edu) and Jeffrey Thayer (University of Colorado at Boulder, Jeffrey.thayer@colorado.edu)

The workshop invites inputs and discussion on long-term trends and the scientific measurements that are most critical to these studies. These discussions will also provide background science rationales and justifications for CEDARs' long term archival strategy. Even the term "long term" is open for discussion. For example, with the CEDAR ISR network running month long studies, do these represent a "long term" database?

Selected speakers are:

1. Jan Sojka, Opening comments
2. Rick Niciejewski, CAWSES Working Group: Climatological Variations of the Ionosphere and Upper Atmosphere
3. Doug Drob, MSIS and HWM empirical models
4. John Holt, Ionospheric Climatology
5. Peter Fox, CEDAR Database Climatologies and Virtual Observatories
6. Susan Nossal, Geocorona Trends
7. Joe She
8. Vince Eccles
9. Irfan Azeem

(Anasazi North, 40) TIMED/CEDAR Collaborative Atmospheric Dynamics, with conveners Elsayed Talaat (APL/JHU, elsayed.talaat@jhuapl.edu), Jeng-Hwa Yee (APL/JHU), Scott Palo (University of Colorado) and Irfan Azeem (Embry-Riddle Aeronautical University)

13:00-15:00 PM1

(Anasazi South, 22) Optical Calibration Techniques and Issues, with conveners Susan Nossal (University of Wisconsin, nossal@wisp.physics.wisc.edu), Michael Taylor (University of Utah) and Thomas Slanger (SRI International)

Calibration is important for comparing observations taken by different instruments, for model-data comparisons, and for acquiring long-term data records. The Optical Calibration workshop at this year's CEDAR conference addressed both absolute intensity and line center calibration methods. In addition, there was discussion concerning the need for publication and/or other documentation of calibration techniques to enable students and other researchers to calibrate their instruments and to understand the techniques used by other observers with whom they might compare data. Another idea proposed to share knowledge about calibration is to have hands-on, interactive calibration demonstrations at a future CEDAR meeting.

D. Pallamraju described the absolute intensity calibration of observations made with the ground-based Boston University spectrograph. Determination of the absolute brightness requires accounting for factors including the filter transmission, the solid angle field of view, vignetting (cutting off of light rays within the instrument), cosmic ray hits on the CCD detector, as well as characteristics of the absolute brightness calibration reference. Similar considerations are required for the calibration of other passive optical spectrometers and imagers using CCD detection. The Boston University Imager is calibrated using a Keo incandescent lamp source that has been cross-calibrated with a similar Stanford source.

John Meriwether followed with a discussion of a cerium hallow cathode Secondary Standard source developed by Fred Biondi for thermospheric zero wind determination. The Cerium line (630.02 nm) is very close spectrally to the OI sky emission (630.03 nm). The secondary source method provides an alternative to the use of zenith observations for zero wind determination, thus reducing the uncertainty in the measurements. The uncertainty associated with determination of the wavelength difference between the OI 630.03 nm line and the Cerium 630.02 nm line corresponds to an equivalent velocity uncertainty of about 34 m/s.

Rick Niciejewski then turned to the line center calibration of satellite wind observations taken with the TIDI instrument, a Fabry-Perot Interferometer on-board the TIMED satellite. Accurate line center determinations are required for accurate wind measurements made by comparing Doppler shifts in the spectral emission to the line center reference. Initially, the average of the zonal mean of the meridional wind component about the equator during equinox was taken as the zero wind reference. However, long-term statistics indicated systematic variations in the wind trend. Corrections for these variations required high precision knowledge of the satellite attitude and monitoring of thermal gradients on the instrument. After such corrections, the TIDI measurements are now able to reach an accuracy and precision of a few m/s in the horizontal wind vector.

Pamela Loughmiller ended the session with a discussion of the intensity calibration of the Cornell All-sky Imager. The Cornell CCD-based Imager is calibrated for brightness using the same white incandescent KEO lamp source used to calibrate the Boston University spectrograph. To determine the intensity of the imager data, multiple factors must be considered including the filter transmission, variations in pixel sensitivity, vignetting within the instrument, the spatial mapping of the sky onto the detector, as well as the characterization of the absolute intensity KEO reference source. Pam also spoke about the need for calibration publication/documentation to assist students and researchers with calibration of their own instruments and with understanding of methods used for other instruments. One purpose of such documentation would be to clarify terms such as "flat field" that are used with different meanings by different observers when discussing calibration methods. Pam outlined such documentation that she has drafted regarding calibration of the Cornell imager.

In addition, Tom Slanger from SRI and John French from the Australian Antarctic Division submitted contributions to the workshop, but were not able to attend. Their presentations are also on the CEDAR website. Tom Slanger's addresses corroboration of intensity calibration using knowledge of atomic and molecular line spectral intensity ratios. John French describes calibration of their Czerny-Turner grating spectrometer and Bomem Fourier-transform spectrometer, both used to measure OH rotational temperatures in the mesosphere over Davis, Antarctica. The presentations by each of the speakers are posted on the CEDAR website.

(Anasazi North, 46) Global Electrodynamics and Storm Effects at Mid and Low Latitudes, with convener Timothy Fuller-Rowell (NOAA, tim.fuller-rowell@noaa.gov)

The workshop provided the first opportunity for the PIs selected by NASA's Living With a Star Focused Science Topic (LWS-FST) on "Storm effects on the global electrodynamics and the middle and low latitude ionosphere" to present their proposals to the rest of the team. Recent observations have revealed that the response of the mid and low latitude ionosphere and thermosphere to geomagnetic storms is much more dynamic and dramatic than previous envisaged. In particular, understanding the role of global electrodynamics in plasma redistribution is a topic of intense interest. This LWS-FST targets this science question. The workshop was a natural follow-on to the morning workshop on penetration electric fields; the morning session focused on some aspects of our current understanding and the afternoon session addressed future research plans.

The team consists of the following PIs and research titles:

• John Foster - Multi-instrument investigation of inner-magnetosphere/ionosphere disturbances
• Tony Mannucci - Ionospheric behavior during the first few hours of intense geomagnetic storms
• Bela Fejer - Storm-time ionospheric electric fields
• Pontus Brandt - Storm-time sub-auroral electric fields: Ionosphere and magnetospheric control
• Ray Greenwald - Understanding the evolution and impacts of storm-enhanced electric fields in the mid-latitude ionosphere
• Elsayed Talaat - Sub-auroral polarization streams effects on the ionosphere and thermosphere
• Stan Sazykin and Tim Fuller-Rowell - Modeling the impact of storm-time electrodynamics on the mid and low latitude ionosphere

The workshop provided an ideal opportunity to begin the communication, for each PI to state what they think are the important science questions within this LWS FST, and to describe their approach to tackling the problem. The workshop spanned both the traditional CEDAR and GEM disciplines, so was held on the last day to give GEM scientists the opportunity to include it in their travel plans. This was a chance for the team to hear about each others plans and start to think about how we can interact and collaborate. The workshop was followed by the first formal meeting of the science team in Boulder to define the integrated three-year research plan.