Characteristics of Rain Integral Parameters during Tropical Convective, Transition, and Stratiform Rain at Gadanki and Its Application in Rain Retrieval

Abstract

Abstract In the present study the characteristics of rain integral parameters during tropical convective (C), transition (T), and stratiform (S) types of rain are studied with the help of Joss–Waldvogel disdrometer (JWD), L-band, and very-high-frequency wind profilers at Gadanki (13.5°N, 79.20°E). The classifications of three regimes are made with the help of an L-band wind profiler. For rain rate R < 10 mm h−1 larger drops are found in S type of rain relative to C and T rain, and for R ≥ 10 mm h−1 larger drops are found in convective rain. Empirical relations are developed for Dm–R, Dm–Z, N*0–R, Z–R, and Z/Dm–R by fitting the power-law equations. Event to event, no systematic variation of the coefficients and exponents could be found for Z–R and Z/Dm–R relations during the three types of rain. Overall, the C and S events are found to be number controlled, and T events are size controlled. During C type of rain, bigger mean raindrops are found during the presence of strong updrafts. During S type of rain, bigger mean raindrops are found to be associated with the higher mean thickness of the bright band and strong velocity gradient. For each of the developed empirical relations, the correlation coefficients are found in the order of T > C > S rain. During the three types of rain, correlations are found in the order of Z/Dm–R > Z–R > Dm–Z > Dm–R. Significant improvement is observed in rain retrieval by using the Z/Dm–R relation relative to the conventional Z–R relation. By utilizing the Z/Dm–R relations, the root-mean-square error was reduced by 19%–46%.