A climatological study of the tropospheric circulation over the amazon region

Clímatological and monthly means are computed for radiosonde data at Manaus and Belém (1968-1976). Geopotencial height and wind data at upper leveis show evidence of the meridional movement of a strongly divergent high pressure system associated with the area of maximum convection. At low leveis, the wínds, partícularly at Manaus, show an annual cycle linked to the meridional displacement of the equatorial trough and its accompanying area of maximum convectlon (upper levei high pressure system). On the average, the precipitable water (Pw) is greater at Manaus than at Belém . However, evidence is presented indicating that this is not always the case and that considerable diurnal variation in Pw exists at each station. Mean monthly vertical motions are calculated for the area withln the tr iangle formed with Belém, Manaus and Vílhena as the vertices. These vertical motions show a strong relationship to monthly rainfall totais within the triangle indicating that interannual and monthly rainfall variations may be due to large scale atmospheric circulation changes.