Diurnal Variations during the Australian Monsoon Experiment (AMEX) Phase II

Abstract

Abstract The diurnal variations in tropical cloudiness and tropospheric winds during the Australian Monsoon Experiment (AMEX) Phase II are documented and compared to those observed elsewhere. A diurnal variation in tropical cloudiness was found to be a consistent feature of both disturbed and undisturbed conditions. The tropical cloudiness, as inferred from satellite and radar data, averaged over the entire period of AMEX Phase II, was at a maximum during the morning over the ocean and during the late afternoon over the Arnhem Land region of northern Australia. The diurnal variation in high cloud, as measured by satellite was 3:2 over the ocean and 4:1 over Arnhem Land. Radar data indicated a 1 0: 1 variation in convection over Arnhem Land, a 2:1 variation over the neighboring ocean and a 3:2 variation in the stratiform echoes over both Ambem land and the neighboring mean. Interaction between local circulations and the large scale flow was found to he associated with the observed diurnal variations in tro...