The 16-day waves in the mesosphere and lower thermosphere over Wuhan (30.6°N, 114.5°E) and Adelaide (35°S, 138°E)

Winds from a meteor radar at Wuhan (30.6 degrees N, 114.5 degrees E) and a MF radar at Adelaide (35 degrees S, 138 degrees E) are used to study the 16-day waves in the mesosphere and lower thermosphere (MLT). The height range is 78-98 km at Wuhan and 70-98 km at Adelaide. By comparison, it is found that the zonal components at both sites are generally larger than the meridional ones, and eastward motion of the zonal background winds is favorable for the 16-day waves penetration to the MLT region. The zonal maximum amplitude appears in the autumn (September-October) around 86-98 km at Wuhan and in the winter months and early spring (July-October) around 72-82 kin at Adelaide. Differences are found in wave amplitudes and time of appearance between the two years of 2002 and 2003. In 2003, the intensity of the wave amplitudes is relatively smaller than that for 2002 at both sites. The summer 16-day waves are comparatively weaker at. Adelaide in both years, but stronger in 2002 at Wuhan near the mesopause and the lower thermosphere (86-98 km). The strong summer waves at Wuhan may come from the winter southern hemisphere. (c) 2005 COSPAR. Published by Elsevier Ltd. All rights reserved.