Impact of special observations on the numerical simulation of a heavy rainfall event during ARMEX-Phase I

Abstract

The heavy rainfall event over west coast of India during 26 - 28 June 2002 (ARMEX Phase - I) is simulated using a high-resolution mesoscale model-NCAR MM5. Two experiments were made with and without the inclusion of special observations of ARMEX – Phase I along with Quickscat and SSM/I surface winds. NCAR MM5, with four nested domains of 81, 27, 9 and 3 km resolutions, is integrated for 72 hr from 0000 UTC of 25 June 2002. The initial and boundary conditions are derived from NCEP analysis at 1 - degree resolution. Quantitative precipitation estimates and the wind fields from MM5 output are analysed.  The model results indicate the formation of a mesoscale convective system and associated heavy rainfall on 27 and 28 June 2002. The model could predict heavy rainfall upto about 30 cm/day though some observations at isolated locations are up to 50 cm/day. Experiment with the inclusion of ARMEX observations and satellite wind data seem to improve the prediction of the location of the maxima and the movement of the rain band but with a slight decrease in the intensity of the heavy rainfall.