Earth Planets Space, Vol. 58 (No. 6), pp. e25-e28, 2006E-LETTER
K.-H. Kim1, Y.-J. Moon1, K.-S. Cho1, H.-D. Kim2, and J.-Y. Park1 Tomoko Nakagawa1 and Masahide Iizima2
1Korea Astronomy and Space Science Institute, Daejeon, Korea
2Korea Aerospace Research Institute, Daejeon, Korea
(Received March 4, 2006; Revised May 1, 2006; Accepted May 5, 2006; Online published June 2, 2006)
We examine the atmospheric drag on the low earth-orbiting satellite, KOMPSAT-1 in a sun-synchronous orbit at ~685-km altitude starting in 1999, during a 3-month (October-December) period in 2003. This 3-month interval includes the October 29-30 and November 20 magnetic superstorms and weak to moderate storms. We observed that the daily KOMPSAT-1 drag acceleration transiently responses to transient storm-time disturbances. That is, there is an one-to-one correspondence between the KOMPSAT-1 drag accelerations and the storm events. We find that the drag acceleration correlates strongly with the level of geomagnetic disturbance. This indicates that the trajectory of KOMPSAT-1 is significantly perturbed during extremely disturbed intervals because of atmospheric density increase. The main contributor to the density increase is Joule heating associated with the geomagnetic activity rather than the solar EUV radiation, as reported by previous studies. We suggest that understanding how the upper atmosphere responses to the geomagnetic-associated heating is important to predict space weather impacts on low earth-orbiting satellites.
Key words: Atmospheric drag, geomagnetic storm, space weather.