Study of radar bright band over a tropical station

According to the information available in open literature the transition height between liquid particles below and freezing particles above is close to 0 Deg C isotherm height( freezing level height) in stratiform rain, whereas in convective rain the transition height is expected to go above freezing level height because of large scale mixing of different particle types. Strong vertical air motion in convective cells lifts up liquid drops upward thereby leaving them in super cooled state.

In this paper an attempt has been made to study the relative position of the transition height and freezing level height over Trivandrum, a tropical station in India with special emphasis to convective rain. Level of peak cloud liquid water(CLW) has been identified over the station during January-December in the year 2007. An attempt has been made to find out if the peak CLW level corresponds to the bright band peak. Statistics of bright band has been presented. The study has been performed using rainfall data of Microwave Imager ( TMI) onboard TRMM during convective episode and freezing level and as well as bright band height data of precipitation radar(PR) onboard TRMM over Trivandrum. The study also includes freezing level height data measured by radio sonde as ground truth to check the validity of PR estimated freezing levels.