Instruments:pkr

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Poker Flat MST Radar

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Acknowledgments

The Poker Flat MST radar was operated by the NOAA (National Oceanic and Atmospheric Administration) Aeronomy Laboratory with support from the National Science Foundation (NSF).

Instrument Description

The Poker Flat MST radar was located at the Poker Flat Rocket range about 200 m above mean sea level in Alaska at (65.13N, 145.46W), and operated between 1979 and 1987. The last 2 years are not in the CEDAR Data Base. The inclination angle is about 77 degrees, and the declination is about 29 degrees to the east of north.

The Poker Flat radar was a high power radar, with three narrow beams. One beam looked vertically (kindat=20003) and the other two were inclined at 15 degrees to vertical, or at an elevation angle of 75 degrees. The 'east' beam had an azimuth 26 degrees north of east (kindat=20001) while the 'north' beam had an azimuth 26 degrees west of north (kindat=20002). Most of the data were taken using all three beams but some, especially in the early days, were taken with only the vertical beam or with only the oblique beams. During an experiment one or more beams were sometimes inactivated. The cycle time for a complete set of vertical and oblique records seldom exceeded 10 min and was typically 1 min. When available, velocity measurements from the two oblique beams were combined to give eastward and northward components of the neutral wind (kindat=20004). The velocity spread is twice the square root of the second moment of the power spectrum and is a measure of shear or turbulence in the measurement volume.

Data quality below 5 km is definitely dubious and below 8 km should be treated with suspicion due to recovery problems. The more obviously false data have been removed from this data set but consistently false data are hard to distinguish from the real thing and may be included.

The original Poker Flat data set has been subjected to an extensive set of checks to remove various interference modes, outliers and otherwise non-atmoshperic data. The parameters for the remaining data have been averaged for all appropriate records that commenced within a one hour interval. Note that these are averages of the derived parameters and not parameters derived from an average velocity spectrum.

In the absence of any signal echo the main contribution to noise is the radio noise from our galaxy. Hence there is a siderial variation (of about 4 db) in the noise level. Atmospheric absorption events reduce the level of noise. Receiver gain and cable attenuation fluctuations may have a small influence. Operator modification of gain controls are rare. Strong signals can corrupt the computation through their sidelobes. The errors given are the root mean square values of the deviation from the mean for that hour.

There are 4 areas in the summary plots for neutral velocities for four 2-day periods between 0 and 80 km. When both eastward and northward velocities are available, there are vector plots for every 3 km where eastward is to the right and northward is upward. When horizontal vectors are unavailable, the vertical neutral velocity is plotted as line plots every 5 km. When only 1 oblique beam is available (only the 'east' beam), an image plot of the line-of-sight (l-o-s) velocity is made for 3 km bins.

References

Balsley, B. B., W. L. Ecklund, D. A. Carter and P. E. Johnson, The MST radar at Poker Flat, Alaska, Radio Sci., 15, 213-223, 1980.
Hardy, K. R. and K. S. gage, The history of radar studies of the clear atmosphere, Chapter 17 of Radar in Meteorology, editor D. Atlas, Am. Meteorological Soc., Boston, 130-142, 1990.
Rottger, J., The MST radar technique, Handbook for MAP (Middle Atmosphere Physics), Vol. 13, 187-232, 1984.

Summary Plots for Poker Flat MST Radar

-Revised 24 Sep 2003 by Barbara Emery

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