Precipitation characteristics of typhoon Lekima (2019) at landfall revealed by joint observations from GPM satellite and S-band radar

摘要

Radar and satellite joint observation data can provide a more efficient way to study landfalling typhoon precipitation, but rarely does this combination of circumstances occur. In this study, we attempt to reveal the precipitation characteristics of typhoon Lekima (2019) at landfall by using joint observations from GPM satellite and S-band Doppler radar. The results suggest that the precipitation microphysical mechanisms are different among typhoon eyewall (EW), inner rainband (IR), and outer rainband (OR) during landfall. Beneath melting layer, collision-coalescence process dominates the precipitation in EW region, with large-/mid- size raindrops (-1.6 mm) as the main components of precipitation. Collision-coalescence, breakup, and evaporation processes are in near balance within the precipitation of IR region, leading to prevailing mid-/small- size raindrops (-1.3 mm) of this region. Melting and evaporation processes are the main precipitation microphysical mechanism in OR region and a small amount of large-size drops (-1.7 mm) constitute the majority of precipitation. Moreover, the large values of radar spectrum width exhibit an appreciable correlation with satellite detected effective reflectivity (Ze) center, mass-weighted mean diameter (Dm) center, and storm top height (STH) peak, jointly indicating the strong convection activity inside landfalling typhoon Lekima, which further enlightens us to make better use of joint observation data from Doppler weather radar and GPM satellite to analyze the microphysics and dynamics associated with heavy rainfall during typhoon landfall in operational applications.