Predicting storm-time thermospheric mass density variations at CHAMP and GRACE altitudes
Orbit-averaged mass density measurements derived from the satellites CHAMP and GRACE are used to investigate the storm-time prediction model developed by Liu et al. (2010) at different altitudes. This model uses as input only the solar wind merging electric field. From 2002 to 2005 in total 31...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2011-03-01
|
| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/29/443/2011/angeo-29-443-2011.pdf |
| Summary: | Orbit-averaged mass density measurements derived from the
satellites CHAMP and GRACE are used to investigate the storm-time prediction
model developed by Liu
et al. (2010) at different altitudes. This model uses as
input only the solar wind merging electric field. From 2002 to 2005 in total
31 major geomagnetic storms with minimum Dst<−100 nT are selected for a
statistical study. The results show that the model can successfully predict
the storm-time mass density changes at both CHAMP and GRACE altitudes. The
orbit-averaged density of CHAMP and GRACE show very similar distribution in
shape, regardless of the orbital local time difference, but the amplitude of
GRACE density is about 30% of that of CHAMP density. An optimal delay time
of 4.5 h has been found for both CHAMP and GRACE densities. During the four
years the scale factor <I>a</I> between merging electric field and mass density
for CHAMP altitude remains basically at the same level, <I>a</I>=0.5, while the
<I>a</I> for GRACE density shows a declining trend, and its value is only 30% of
that for CHAMP density. The storms driven by corotating interaction regions
(CIR) have in general larger <I>a</I> values than the storms driven by coronal
mass ejections (CMEs). |
|---|---|
| ISSN: | 0992-7689 1432-0576 |