Vertical circulations and heat and moisture budgets in the time-mean July atmosphere over India and Bay of Bengal

Abstract

Vertical circulations obtained by combining vertical motion with the components of horizontal motion suggest the existence of Walker, Hadley and monsoon type cells in certain narrow latitudinal and longitudinal sections across the monsoon through zone in the time-mean July atmosphere over India and neighbouring Bay of Bengal. The deduced vertical circulation cells appear to be consistent with the distributions of diabetic heating and cooling computed from heat and moisture budget and rainfall computed from the moisture budget equation, The heat budget suggests that to a close approximation, Q/cp~aw (where Q is the rate of diabetic heating, Cp is the specific heat of air at constant pressure, w is the vertical p. velocity and a is the static stability parameter) over this region as well as found m some other parts of the monsoon belt, The Importance of a vertical circulation, cell forced by the mountain systems , of eastern Himalayas in the maintenance of the monsoon trough and the distribution of rainfall over north India is discussed.