Mean vertical motion and non-adiabatic heat sources over India during the monsoon

The mean vertical velocity in pressure coordinates, and the corresponding height tendency, was computed at intervals of 100 mb from 1000 mb to 60 mb on a mesh covering India and most of southeast Asia. The rate of non-adiabatic heat supply was expressed as a function of the computed height tendency. The results showed pronounced ascent over northeast India and a zone of subsidence over northwest India. The rate of ascent decreased uniformly with pressure suggesting force ascent on account of orographic features to the north of India. The computed values of the height tendency indicated that non-adiabatic heat sources must be capable of producing an average warming at the rate of 1.6 C(12hr)-l in northeast India, and an average cooling by 1.2 C(lPhr)-' in northwest India.