PUMPING AT STEADY CUMULUS BASE AND HALTINER’S AIR COLUMN MODEL

It is presented that there is a pumping effect at its base in the development process of a cumulus.In the strongest stage of cumulus development,the pumping is mainly produced by the buoyance at the base,and may be taken as the first approximation of the ascending speed at the base.The results of numerical calculations and simulations of four observed radar echoes show that as the first approximation,the height of air-mass cumulus may be simulated by Haltiner model in the absence of observed ascending speeds at the base,and the Haltiner model can be characterized by the sensitivity of the cumulus development to the virtual temperature excess over environment at the base.