Role of Condensed Water in the Life Cycle of a Convective Cloud

Abstract

The effects of precipitation formation in convective clouds are studied numerically with the help of a one-dimensional steady-initial-state model of convection in a nonviscous adiabatic atmosphere, incorporating the negative buoyancy of the products of condensation. The conclusions are: (i) the formation of precipitation leads to storage of water in the cloud which (ii) decreases both the strength and vertical extent of the updraft; (iii) the downdraft that appears near the base of the cloud as a result of the negative buoyancy of the water stored in that region builds downward on account of evaporative cooling in subcloud layers; (iv) large drops are generally more effective than small ones in causing surface downdraft and rain; and (v) for similar physical conditions more vigorous clouds have the potentiality of giving more rain. Limitations of the model are also discussed.