Temperature and wind tides around the summer mesopause at middle and arctic latitudes

Abstract

Temperatures and winds have been determined with a meteor radar at middle and arctic latitudes. Temperatures are estimated as daily averages around 90 km and winds as hourly means between about 82 km and 98 km. Tides are extracted by a superposed epoch analysis using data from periods of typically 10 or 20 days. The variability of meteor radar temperatures and winds obtained at mid-latitudes during summer in 2000 and 2001 as well as at arctic latitudes in summer 2002 is discussed. The observed low temperatures in early summer (150–170K at 54°N and 120–130K at 69°N) are correlated with the appearance of strong mesospheric radar echoes in the VHF range and of noctilucent clouds at arctic latitudes. At mid-latitudes the amplitudes of the diurnal and semidiurnal temperature tide are in the order of 5 K during summer. The tidal amplitudes at arctic latitudes are smaller with about 4 K for the diurnal tide and 2 K for the semidiurnal tide. The steep temperature decrease from spring to summer at mid-latitudes is accompanied by an enhanced semi-diurnal temperature tide (7–10 K) between middle of May and middle of June.