Analytical Application of Three Kinds of New Observation Data in a Spring Short-time Severe Precipitation Process in Guiyang
Based on the conventional meteorological data,ERA5 reanalysis data,and the wind profile radar,ground-based microwave radiometer and disdrometer observation data in Guiyang region,this article analyzes a short-time severe precipitation process that occurred on March 16,2023,and discusses the application of new detection data in the monitoring and early warning of short-time heavy precipitation.The results show that:(1)In 2 h earlier than the occurrence of short-term heavy rainfall,the vertical motion was weak,and strength center of the vertical wind shear propagated downward.In about 0.5 h ahead of the precipitation,the vertical velocity of 0～7 km increased significantly,the vertical motion of lower layer was more remarkable,the positive vertical wind shear strengthened significantly,and the low-level jet index increased rapidly.(2)From 19:00 to 21:00,the atmospheric liquid water content was increasing by fluctuation.Under the influence of dry air intrusion,the relative humidity below 1 km decreased,thus the atmosphere in the height range of 0～8 km formed a three-layer structure of"dry in the upper and lower layers but wet in the mid layer".In about 0.5 h before precipitation,the content of atmospheric liquid water increased rapidly so that the three-layer structure changed into a two-layer structure of"dry at the top and wet at the bottom".The severe precipitation occurred when the content of atmospheric liquid water peaked.(3)The convection process was in a high-energy environment.The K index began to exceed 35℃ in the afternoon,and in 0.5 h ahead of the precipitation,both the K index and CAPE had a large jump.At the time of precipitation,the low-level jet of strong southwest wind brought warm and moist air,forming a temperature inversion layer at the height of 0.2～1 km with a significantly maximum temperature center higher than 25 ℃.(4)The relationship between raindrop diameter and falling velocity in this short-time heavy precipitation process was in line with the theoretical relationship,and the medium-sized particles contributed most for the precipitation intensity.During the precipitation period,the raindrop size distribution had an obvious bimodal structure.The above results show that the new observation data can meticulously capture the small and medium scale characteristics before the occurrence of short-time severe precipitation.The significant increase in vertical velocity,low-level jet index and atmospheric liquid water content indicate that precipitation is about to begin.There is a good correspondence between the fluctuation of low-level jet index and rainfall intensity.In addition,the increase of 0～1 km vertical wind shear is a good predictor for the occurrence of heavy precipitation.
Guiyangwind profile radarground-based microwave radiometerraindrop size distributionshort-time severe precipitation
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