Journal of the Marine Biological Association of India

Volume 14 Issue 2

Satellite clouding associated with the monsoon trough

N. S. Bhaskara Rao,N. N. Khambete and K. S. Joshi

The ITCZ shifts much more northwards during the northern summer in the North Indian Ocean than anywhere else in the world and the axis of the low pressure belt associated with it lies over South Asia at the sea level. The other noteworthy features of the circulation over South Asia and the enclosed seas of the North Indian Ocean are (1) the existence of a broad belt of westerlies from the equator to the south of the axis extending to a height of about 6 km and (2) the southward shift of the axis of the low pressure belt with height.

The perturbations embedded in the deep and highly moist monsoon air cause plentiful rainfall, but the rainfall distribution is highly asymmetric with respect to the surface position of the disturbances. The Television cloud pictures received from satellites show clearly the areas of maximum hydrometeor activity. They appear as highly bright blobs elongated east to west. Several such blobs can often be noticed on an APT picture-mosaics and an axis can be drawn, which passes through the central areas of such blobs.

The cloud belt axis was compared with position of the axis of the monsoon trough at different levels. The results show that the cloud axis coincides best with the axis of the Monsoon trough at the 700/500 mbs and least with that at the surface under normal monsoon conditions.

Date : 30-12-1972