A diagnostic study on heat sources and moisture sinks in the monsoon trough area during active-break phases of the Indian summer monsoon, 1979

Abstract

The diabatic heating over the Indian monsoon trough area, along with its thermal structure are studied for the 1979 summer monsoon based on FGGE level-IIIb upper air data of the European Centre for Medium Range Weather Forecasts. The apparent heat source and the apparent moisture sink over the trough area varied coherently with the rainfall over central India. The spatial and temporal variations of the vertically integrated apparent heat source and moisture sink were found to be coincident. These coincidences suggested that diabatic heating was largely contributed by the latent heat released by cumulus convection. During the active periods, the vertical structure of spatially-averaged heating and drying rates above the monsoon trough area showed higher values, as much as 8 K to 11 K day