Wintertime mesopause temperatures observed by lidar measurements over Syowa station (69°S, 39°E), Antarctica

Abstract

A sodium lidar at Syowa station (69°S, 39°E), Antarctica, measured temperature profiles from 80 to 110 km between March and September during 2000 and 2001. Monthly averaged temperature profiles in the mesopause region in wintertime (June, July and August) are nearly 20 K lower than those in the northern hemisphere sites. The measured winter mesopause altitudes (∼99 km) are in good agreement with those measured at Fort Collins (41°N) and Andøya (69°N) in winter. The mesopause temperatures (∼175 K) in winter months however are about 20 K lower than those observed from a northern hemisphere conjugate site, Andøya. The lower winter mesopause temperatures measured at Syowa station, which are consistent with southern hemisphere mesopause temperatures measured by a shipborne lidar, suggest the existence of a hemispheric difference. Possible causes for this difference are discussed.