A comparison of the effects of CIR- and CME-induced geomagnetic activity on thermospheric densities and spacecraft orbits: Case studies

So far studies of the effect of geomagnetic storms on thermospheric density and satellite orbits have been mainly focused on severe storm events caused by Coronal Mass Ejections (CMEs). The effect of long‐duration, less intensive geomagnetic activity that is related to Corotating Interaction Regions...

Full description

Saved in:
Bibliographic Details
Published in:Journal of Geophysical Research: Space Physics 2012-08, Vol.117 (A8), p.n/a
Main Authors: Chen, Guang-ming, Xu, Jiyao, Wang, Wenbin, Lei, Jiuhou, Burns, Alan G.
Format: Article
Language:English
Subjects:
Atmospheric sciences
CIR
CME
Earth sciences
Earth, ocean, space
Exact sciences and technology
orbit
storm
thermospheric density
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:So far studies of the effect of geomagnetic storms on thermospheric density and satellite orbits have been mainly focused on severe storm events caused by Coronal Mass Ejections (CMEs). The effect of long‐duration, less intensive geomagnetic activity that is related to Corotating Interaction Regions (CIRs) has not been fully explored. In this paper, thermospheric densities observed by the CHAMP satellite and its orbit parameters are used to compare the responses of satellite orbital altitudes to geomagnetic activity caused by CMEs and CIRs. Three cases are investigated in this paper. Each case had one or two CME storm(s) and one CIR storm that occurred successively. In these cases three out of four CME‐storms were stronger than their corresponding CIR‐storms, but the durations of these CME‐storms were much shorter. Thus, the satellite orbit decay rates during CME‐storms are usually larger than those during CIR‐storms. However, CIR‐storms often had long durations that perturbed satellite orbits for longer periods of time. As a result, the total thermospheric density changes and satellite orbit decays for the entire periods of CIR‐storms were much greater than those for the CME‐storms since these parameters were related to the total energy deposited into the thermosphere/ionosphere, which depended on both the strengths and the durations of the storms. This study indicates that more attention should be paid to CIR storms during the declining phase and during solar minimum, when they occur frequently and periodically. Whereas fewer CME storms occurring under these conditions. We also found that changes in thermospheric densities and CHAMP orbit decay rates correlated well with variations of auroral hemispheric power, but lagging by about 3–6 h. Key Points The responses of satellite orbits to CME and CIR storms are studied Total satellite orbit decays during CIR storms should be paid attention to Changes in orbit decay rates correlated with those in auroral hemispheric power
ISSN:0148-0227
2169-9380
2156-2202
2169-9402
DOI:10.1029/2012JA017782