Geoscience Reference
In-Depth Information
Fig. 4.9
Model calculations of the high-latitude thermospheric neutral wind circulation at 400-km
altitude, presented here in the same format as in Fig.
4.2
as wind vector pattern in polar
geomagnetic coordinates at latitudes higher than 60
ı
(Northern Hemisphere). The four panels show
the wind pattern at four UT moments (06, 12, 18, and 24 UT) on 28 October 2003 as obtained with
the theoretical upper atmosphere model, UAM. Maximum wind speed is 700 m/s in the dusk sector
at 18 UT and within the polar cap area at 24 UT
of CHAMP on 28 October 2003. This comparison revealed a close agreement
between them during certain overflights and discrepancies during others. One
characteristic example of a Northern Hemisphere crossing is shown in Fig.
4.10
.
The dotted line symbolizes the CHAMP satellite trace over the polar region with
the triangle indicating the actual position at the given time moment (17:12 UT).
The projection of the modeled 2-D thermospheric wind vector on the cross-track
