Mean winds of the upper middle atmosphere (∼70–110 km) from the global radar network: Comparisons with CIRA 72, and new rocket and satellite data

Abstract

A substantial quantity of wind data have been assembled from radar systems since CIRA-72 was formed: most of these radars include height ranging, and operate on a regular and even continuous basis. Systems include meteor and MF (medium frequency) Radars: an MST (mesosphere-stratosphere-troposphere) Radar (meteor mode); and an LF (low frequency) drift system. Latitudes represented are near 20° N/S, 35° N/S, 45° N/S, 50°N, 65° N/S. In all cases tidal oscillations were calculated so that corrected mean winds (zonal, meridional) are available - the meridional was not included in CIRA-72. Means for groups of years near 1980 are available, as well as individual recent years (1983, 1984) to allow assessment of secular trends: revised and improved analysis has been completed for several stations. Height-time cross-sections have been formed for each observatory: heights are typically ∼75–110 km, with time resolution of 7–30 days. Such detailed cross-sections were almost unknown before 1972. Comparisons with CIRA-72 are shown, and these emphasize the differences between hemispheres (NH, SH) in the radar winds. Other new winds from rockets and satellite radiances are contrasted with the radar set. There are important differences with the satellite-derived geostrophic winds (1973–78): possible explanations involve secular trends, longitudinal variations, and ageostrophy.