An investigation into the relationship between surface rain rate and rain depth over Southeast Asia

Abstract

The relationship between surface rain rate and depth of rain system (rain depth) over Southeast Asia is examined using 10-yr Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) measurements. Results show that, in general, a large surface rain rate is associated with a deep precipitating system, but a deep rain system may not always correspond with a large surface rain rate. This feature has a regional characteristic. Convective rain develops more frequently over land than over the ocean, while stratiform rain can extend to higher altitudes over the ocean than over land. A light surface rain rate has the largest probability to occur, regardless of rain depth. A convective rain system is more likely associated with a stronger surface rain rate than a stratiform rain system. Results show that precipitation systems involve complex microphysical processes. Rain depth is just one characteristic of precipitation. A linear relationship between surface rain rate and rain depth does not exist. Both deep convective and stratiform rain systems have reflectivity profiles that can be divided into three sections. The main difference in their profiles is at higher levels, from 4.5 km up to 19 km. For shallow stratiform rain systems, a two-section reflectivity profile mainly exists, while for convective systems a three-section profile is more common.