Vertical structure of raindrop size distribution over West Sumatera from global precipitation measurement (GPM) observation

Abstract

Abstract Vertical Structure of Raindrop Size Distribution (DSD) over West Sumatera (99.82 E – 100.82 E; 0.73 S – 0.27 N) was observed from Normal Scan (NS) of Global Precipitation Measurement (GPM) observation during December 2014 to June 2018. This observation was carried out for stratiform and convective rain. The vertical structure of DSD from GPM was described as two gamma distribution parameters, namely, mass-weighted mean diameter (Dm ) and total raindrop concentration (Nw ). In addition, the vertical structure of integral rainfall parameters was investigated from the vertical structure of radar reflectivity (Z). It was found that vertical structure of DSD from NS of GPM observation shown different value for both stratiform and convective rain, for the same rainfall intensity. The NS of GPM estimates larger (smaller) Dm (Nw ) for convective than stratiform rain. It indicates convective has more large drops than stratiform rain with lower of total drops number for the same rainfall intensity. Furthermore, the gradient of vertically downward from Dm and Nw is slightly larger during convective rain than during stratiform rain for all classes intensity. This indicates a more significant growth of raindrop in rain column during convective rain than during stratiform rain over West Sumatera.