edu.ucar.opensky::articles:22219 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T15:45:59.587606 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7x63qzz The longitudinal variations of upper thermospheric zonal winds observed by the CHAMP satellite at low and midlatitudes 2018-11-01T00:00:00Z publication https://n2t.org/ark:/85065/d7x63qzz https://doi.org/10.1029/2018JA025463 Zhang, Kedeng author Wang, Wenbin author Wang, H. author Dang, T. author Liu, Jing author Wu, Qian author UCAR/NCAR - Library publisher In this work, we investigate the longitudinal patterns of thermospheric zonal winds (similar to 400 km) and their seasonal and solar activity dependence using CHAllenging Minisatellite Payload cross-track wind data and Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) simulations. CHAllenging Minisatellite Payload data show that there are large longitudinal variations in thermospheric zonal winds. These longitudinal variations do not have significant solar activity dependence. In the northern hemisphere at low and middle latitudes, the daytime zonal winds are more westward between -90 degrees and 90 degrees longitudes and more eastward at other longitudes. The nighttime zonal wind direction with pattern is opposite to that in the daytime. In the southern hemisphere at low and middle latitudes, the local time variation of the longitudinal wind structure, including positive and negative peak locations, is almost the reverse of that in the northern hemisphere. Thus, the zonal wind patterns also show great hemispheric asymmetry. In addition, the longitudinal patterns of zonal winds in both hemispheres show seasonal variations. The longitudinal patterns during the June solstice are significantly different from those in other seasons. These observational results are well reproduced in TIEGCM simulations. To elucidate the physical processes responsible for the observed and simulated longitudinal patterns of the zonal winds, the TIEGCM is also run for different geomagnetic field configurations. A comparison between the TIEGCM results shows that geomagnetic field structure is the main cause of the large longitudinal variations of thermospheric zonal winds and their local time, hemispheric asymmetry, and seasonal changes at low and middle latitudes. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2018 American Geophysical Union. None eng geoscientificInformation