Forewarning Analysis and Radar Features for Short-time Heavy Rainfall Based on SWAN System Products

Using SWAN products and precipitation data of automatic meteorological stations to analyze short-time heavy rainfall processes from 2010 to 2012 year,the results showed that there are strong reflection feature,high radar VIL、tall top of radar echo feature and thick depth of strong radar echo(≥45dBZ) during short-time heavy rainfall periods.(1) seeing from every 6min SWAN products,short-time heavy rainfall had some following echo features: CAPPI echo ≥30dBZ(three-dimensional radar echo in SWAN products) at 3km height,center of CR reflectivity ≥40dBZ,radar VIL>5kg/m2,the depth of strong radar echo ≥3km.Variations of these radar factors could be forewarning indexes for short-time rainfall.(2)QPE/QPF products could be beneficial to estimate 1h-accumulate precipitation and position of short-time heavy rainfall in future,but compared to QPF products,QPE products could estimate precipitation and position of short-time heavy rainfall more accurately.Therefore,when monitoring development of strong Radar echo,forecasters can use above SWAN forewarning indexes to forecast short-time rainfall.