Permanent monitoring of the upper atmosphere wind field over Central Europe by a joint analysis of LF windprofiler and MF radar measurements at Collm and Juliusruh (Germany)

Abstract

Continuous monitoring of the mesospheric and lower thermospheric wind field in northern mid-latitudes is carried out by LF windprofiler and MF radar measurements at Collm (51.3°N, 13°E) and Juliusruh (54.6°N, 13.5°E) resp., the centre of the reflection points of the measuring paths is by 52°N and 15°E. A joint analysis of the MF radar observations (70-90 km) and the LF wind profiler measurements (85-110 km) allows the derivation of reliable height-time cross-sections of the prevailing and tidal wind for the height range from 70 to 110 km on the basis of half-monthly profiles. Results are given for 1990 and 1991, which are in general agreement with other cross-sections. The prevailing zonal wind is dominated by the summer mesospheric westward wind system (winds up to 45 m/s around 80 km) and the overlying eastward wind system with typical changes in the direction and vertical gradient during the equinoxes. The meridional winds are southward directed above 95 km in winter and above 80 km in summer. The semidiurnal tidal amplitude shows clear seasonal variations with maxima during fall above 85 km, and the phase positions are shifting rapidly in spring and fall.

Keywords

• mesospheric
• westward wind
• radar measurements
• mesosphärisch
• westwind
• radarmessungen
• collm
• juliusruh
• germany