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Type of abstract: Contributed
Presenter Name: Jian-shan Guo
Status of first author: non-student  
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Title: 
Study of equator-ward transmission of polar disturbances 
--Data assimilative approach

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Authors: 
Jian-shan Guo*  She-ping Shang  Man-lian Zhang  Hong Zheng
Xi-gui Luo  Jiankui Shi  and  Qing-yi Zhang

Laboratory of Space Weather Study, 
Center for Space Science and Applied Research, 
Chinese Academy of Sciences
guo's Email: guojs@center.cssar.ac.cn

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Abstract: 
We discuss the properties of one-dimensional ionospheric 
dynamic transportation based on computer simulation to look 
into the role of data assimilation in atmospheric dynamics 
study in this paper. The physical problem is aimed at the 
equator-ward transmission of polar disturbances with multi-
frequency components along meridian chain in China region in 
a simplified situation. The initial condition is not considered 
that is corresponding to the case of stationary disturbance last 
more than several hours. The observables are ion concentration 
at different locations, where meridian observatory is located, 
along geomagnetic latitude. These observables are subject to 
the ionospheric dynamic equation. On the other hand the ion 
concentration as an observable is interfered by noises 
(instrument error plus environment noise). Here the data 
assimilation is refer to as that the solution must be subject to 
the coordinate variation of the variables under the control of 
the dynamic equation and closest to the optimized values of the 
measured parameters. The noise model is supposed to be 
independent of measured observables, and normal distribution 
with zero average, and covariance of ?. The problem then can 
be described mathematically as solving dynamic equation by 
optimum seeking method. The results based on simulated data 
show that the assimilative solution could be consistent with the 
accurate one as closed as one wish, and the extent of the 
consistence depends on the extent of knowledge one obtained 
of statistic characteristics of the measured data. The sought 
coefficients of the terms of a series solution reveal the 
harmonious components of the simulated disturbances. The 
wave component with wavelength of about a quarter attenuates 
too rapidly (90%) to propagate to middle latitude but the one 
with about an hour propagates to middle latitude attenuating 
63% under the real ionospheric condition. The larger 
wavelength the smaller attenuation. In more realistic cases 
multiple ion transmission needs to consider the interaction 
between the ions and neutral particles, and this leads to a 
complex problem of multi-dynamic equations and multiple 
restrictions in computing technique, and needs to be studied in 
more detail further. 

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Space Weather (part of S-RAMP/SCOSTEP)
Upper Atmosphere and Ionosphere
Analysis Techniques