APPLICATION OF K_DP EVOLUTION ON THE VERY-SHORT-RANGE RAINFALL FORECAST

On 16 October 2021, localized torrential rainfall (> 70 mm h^-1) occurred in the slope area of northern Taiwan during an approaching surface front. Flash floods downstream of the catchment area resulted in a severe drowning accident without warning. In this observational study, the newly-established C-band disaster prevention rainfall radar in northern Taiwan is used for analysis and comparison. At 15-18 local time (LST), extreme values of the specific differential phase K_DP (> 2° km^-1) can be used to identify the heavy rainfall region’s location, intensity, and movement. For flash floods downstream of the catchment area, potentially, there is a priori warning capability. In this event, tracking intense and concentrated K_DP on complex terrain has an advantage over radar reflectivity. The direct application of K_DP on quantitative precipitation estimates can effectively complement the transmission-delay problem of ground rain gauges.