Microphysical features of typhoon and non-typhoon rainfall observed in Taiwan, an island in the northwest Pacific

Abstract. The microphysical features of the typhoon (TY) and non-typhoon (NTY) rainfall in summer seasons are analyzed using long-term (2004 to 2016) data from the impact disdrometer installed in north Taiwan. The RSD stratified based on rainfall rate showed distinct RSD characteristics between TY and NTY rainfall. More (less) number of small (big) size raindrops are noticed in TY rainfall than NTY rainfall. RSD features in terms of gamma parameters are studied for these two weather regimes. The mass-weighted mean diameter (Dm) values are higher in NTY than TY rainfall, and an inverse behavior is observed for the normalized intercept parameter (Nw). Even after separating the rainfall regimes into convective and stratiform type, a large Dm is found in NTY compared to TY precipitation. Distinct variations in Z–R, Dm–R, Nw–R, KE–R, and KE–Dm relations are noticed between TY and NTY rainfall. Possible mechanisms responsible for the RSD variations between TY and NTY are discussed using reanalysis, remote-sensing, and ground-based radar datasets.