Simulation of mesoscale convective systems developed over Bangladesh

Abstract

In and around Bangladesh (88.05°.92 74°E and 20.61""26,63°N) a number of Mesoscale Convective Systems (MCSs) developed durlng the monsOOn Seasons lhal produce heavy precipitation in this region, Due 10 the lack of ooser','ational dala, simulalion ofMCSs is one of the ways 10 undersland its growth and development mechanism. Bearing lhis in mind, fifth generation mesoscale regional model (MM5) of the NCARIPSU is employe<! to analyze 5-case study in different months of 20(J() and 2002. Out of 5 cases, delails analysis is performed on 1 April 2002 case. The simulated MCS of I April 2002 (maximum length -700 km and width ~450 krn) was covered almost Bangladesh and parts of India in lhe NE side of Bangladesh. The meso-syslem was composed 01'9 eloud cells. It< developing stage was - 9 hours. The MCS was in ilS malure stage for about 8 hour,. The Bangladesh Mcteorological Department (BMD) radar PP[ scans data detecl precipitalion in the development sidc of the MCS. The TRMM (Tropical Rainfall Measuring Mission) VS 3842 producls dala al", detected heavy rain in the MCS development region. The analyzed MCS on April 1 2002 is a mcrged lype meso-system lhat developed in a high-pressure. low-temperature and high-humid zone. Low-level south-westerly favored in carrying moislure and heal from lhe Bay of Bengal and central lndian landmass, re'pectively to form the comection. Unstable condLtion exisled in belween 700-500 hPa levels during the development of the system. Other 4 cases are also shows ,imilar results. Finally, il is conelnded that MM5 successfully simulated the MCS developed in and around Bangladesh. However, more research work is necessary on MCS using different model physics and other parameterization in MM5.