A Satellite Meteorological Study of Evaporation and Cloud Formation over the Western Pacific under the Influence of the Winter Monsoo

Abstract

A study of the source regions of winter monsoon clouds in relation to orographic features revealed that the cloud-free paths and the off-shore distance of the initial clouds measured along stream-lines are closely related to the height of the mountains and the intensity of the monsoon. The patterns of clouds after their formation are found to vary according to the vertical wind shear, changing from convection cells with weak shear to transverse bands with moderate shear and longitudinal bands with strong shear. Following the study of cloud formations, the uses of satellite and aerological data in estimating evaporation from the sea surface were explored. It was found that the water content of monsoon clouds is con- siderably smaller than what might be expected through adiabatic rising processes. The ratio of actual to adiabatic water content was estimated to be about 0.6 over the Sea of Japan and about 0.7 over the western Pacific under the influence of a strong winter monsoon.