Research on Short and Imminent Warning Index Technology of Small and Medium Scale Heavy Rainfall in Qianjiang City
XU Qiong-fang, YUE Yang, DU Yan-ni, ZHANG Xin-bei, WANG Quan-min
2018, 57(22):
43-48.
doi:10.14088/j.cnki.issn0439-8114.2018.22.013
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Based on the MICAPS high altitude, ground actual data by hour and Doppler weather radar data,the 23 short-term strong convective weather process in Qianjiang city in 2011-2016 years was analyzed,and the short term and impending early warning index of the middle and small scale heavy rainfall in Qianjiang was summarized,and it was put into use and revised in the short impending forecast business in 2017. The results show that short term heavy rainfall in Qianjiang appears 4 times a year,mostly in April to September,and July is the most frequent month. The background characteristics of short time strong rainfall are front,low trough,shear line,low pressure,low vortex and other weather systems. Before short-term strong precipitation,the physical quantity is characterized by abundant water vapor,thick wet layer,thick warm cloud thickness,0 ℃ layer height at about 5 000 m. The CAPE of convective effective potential belongs to medium strength,and the proportion of one station in 57494 or 57461 K index above 36 ℃ is 91.3%. There are three types of radar echo evolution in short time strong precipitation： Moving in type,which can be divided into general moving type and“train effect” type,combined strengthening type and local development type. The shape of short time heavy rainfall radar echo is mostly ribbon, while vortex band, sheet shape,arcuate shape and vortex formation are less. In short time strong precipitation, more than 6 body reflectance factors are more than 35.0 dBz in 1 hour,strong echo 40 dBZ extends to about 7 km,DVIL is about 2 g/m3,and vertical wind shear value is around 10 m/s.
