Typhoon Nida’s rainfall characteristics in Guangzhou City based on Doppler radar estimation

Abstract

Typhoon is one of the extreme weather systems that causes heavy rainfall in its passing area, which usually induces severe flooding and huge damages. Space-time distribution of Typhoon induced precipitation is quite uneven that is an important factor to cause disastrous flooding. Traditional precipitation observation by ground-based rain gauges network and conventional weather radar cannot provide high space-time resolution data for this analysis. In this study, estimated precipitation based on Guangzhou Doppler Radar, a newly developed weather radar installed in Guangzhou City, is employed to analysis the rainfall characteristics induced by typhoon Nida in 2016 in Guangzhou City, which has high rainfall space-time resolution that time resolution of 1 hour, the spatial resolution of 1km. The results show that the characteristics of rainfall spatial-temporal are uneven distribution. (1) During the typhoon Nida, rainfall in Guangzhou mainly concentrated in two periods: (a) 13 hours before landing and 2 hours after typhoon moving to Guangxi Autonomous Region; (b) 6 hours after typhoon moving to Guangxi to the time typhoon dissipated in the northern part of Guangxi. (2) During the typhoon landing until it moved to Guangxi Autonomous Region, the whole Guangzhou city covered by strong rainfall, and the largest rainfall appeared near the centre of typhoon; after typhoon disappeared, the rainfall in Guangzhou City gradually weakened and the rainfall trend started to weaken.(3) The position of heavy rainfall centre moved following typhoon track, it firstly appeared in the southeast of Guangzhou, then moved to the centre, and after typhoon moved to Guangxi, the heavy rainfall in Guangzhou happened in the west of Guangzhou. (4) In the future, calibrated radar data with high spatial-temporal resolution may be used to analyse the spatial-temporal distribution of precipitation during the typhoon.