Objective analysis on the circulation type and extremes of the 21 July 2012 torrential rain in Beijing

摘要

1.Introduction A torrential rain happened in Beijing on 21 July 2012 (refer to 721) with the observed 24-h precipitation reaching 460 mm,which was the maximum record since 1951 after China begun the relatively complete meteorological observations.This event caused 79 deaths and more than ten billion economic losses.Several works have been conducted to analyse the convective conditions (Fang et al.,2012),structure evolution (Sun et al.,2012) and extremes of this case (Chen et al.,2012,Sun et al.,2012).