| Strong convective weather,thunderstorms,hail,short-term heavy rainfall in Southern China region of China sent more,this kind of disaster weather has the characteristics of short duration,high intensity,dramatic change,will cause strong lightning,high winds,hail disasters,floods and landslides,collapse of secondary disasters,a serious threat to people's normal operation the people's lives and property safety and social economy.Wuzhou is located in the western part of the territory of the Xijiang River Basin,Xunjiang River,Guangxi from Xijiang River is a major river system,Guangdong and Southern China by the strong convective weather in more areas.Before the flood season(4-6 months)due to the cold air activity is still relatively active,warm system of Wuzhou area was significantly enhanced,the convergence of heating system exacerbated the convective weather occurrence and development,therefore,to carry on the statistical analysis of strong convective weather process in Wuzhou before the flood season,and the use of a new generation of Doppler weather radar observation data research the strong convective weather before the flood season,it is of great significance for short-term Nowcasting and warning business to carry out such disaster weather work.Based on the Wuzhou city 5 national meteorological observation stations,154 regional automatic weather observation station measured 2010-2015 years 4-6 months by minute precipitation,wind direction and wind speed data,the main use of a new generation of Wuzhou Doppler radar real-time detection data(every 6 minutes,the individual sweeps)before the flood season of Xijiang River Basin in Wuzhou area(4-6 months statistical characteristics)and Doppler radar echo features of strong convection weather process are analyzed,the process of individual obvious effect,the time range can be extended to March,unified in the first flood season category.The number of strong convective weather in the pre flood season in Wuzhou area was analyzed,and the weather and climate characteristics of various types of strong convection were summarized and analyzed.Study period(2010-2015 years before the flood season)statistics of strong convective weather cases 76.Among them,42,17 cases of thunderstorms and mixed type convective weather short-term heavy rainfall case(at the same time,short-term heavy rainfall and thunderstorms two phenomena)12 case,type II hybrid strong convective weather(and short-term heavy rainfall and hail two phenomena)case 1,mixed type strong convective weather(at the same time,short-term heavy rainfall and thunderstorms and hail three phenomena)case 4,visible,mixed type II and III strong convective weather(and short-term heavy rainfall and hail two phenomena)case is less,not to the mixed type of strong convection weather case more than half.All of the 10% cases of severe convective weather.Analysis of the temporal and spatial distribution characteristics of strong convective weather in Wuzhou area before the flood season,flood season 2010-2015 years ago district(county)strong convective weather case number: Mengshan number 27,Wuzhou number 34,Cangwu city a case number 19,number 34,Tengxian case Cenxi case number 31,can be seen in Wuzhou area the pre flood season in South convection weather cases significantly more than the north.About 2010-2015 years ago in the monthly number of strong convective weather case were analyzed before and 8 cases(mainly appeared in March),in April 14 the number of cases,the cases in May June case number 24,number 30,visible,strong convective weather was gradually increasing trend,also in line with the trend of seasonal variation of active the convective weather.The circulation system of strong convective weather in the pre flood season in Wuzhou is analyzed.The westerly system includes upper trough,shear line and the ground front and low-level jet and the southwest vortex.Among them,there are three main types: North China trough trough,southern trough and plateau trough.The system mainly includes tropical tropical cyclones and associated with the ITCZ,easterly wave.The typical circulation configuration causing strong convection weather in Wuzhou before the flood season is North China trough + plateau trough(or southern trough)together,the upper trough and low-level shear line and the ground front with the strong convection weather case more.Statistics show that before May,Wuzhou strong convective weather mainly by the westerly system,after entering the May,began to appear in the tropical system,but the proportion is not large.Focus on the occurrence of various types of strong convective weather in the former flood season on the performance characteristics of Doppler weather radar in Wuzhou.The short-term heavy rainfall often shows massive echo echo,echo shape smooth,echo intensity in the center of more than 45 dBz;in the upwind velocity features,often appear in the radial velocity.Thunderstorm wind speed characteristics of the radar echo,wind direction with a high degree of clockwise rotation,there is a strong warm advection,in the high elevation of the velocity map(generally elevation at 4.3 degrees)there is a strong wind nuclear presence.And the hail and other cold type shear echo,in the speed characteristic,the zero velocity line appears the 90 degree angle,the wind direction is reversed with the height,can analyze the existence of the cold advection.A detailed analysis of the four strong convective weather process,which is "100602","100609","100615" three times of heavy rain,thunderstorms and hail process,"140329" corresponds to the circulation characteristics of short time heavy rainfall and thunderstorms and hail the three strong convective weather.The analysis result shows that the precipitation intensity and echo intensity 100602 "process is related to the zero line of jagged features and positive and negative phase velocity field configuration,easy to produce in the cyclone,is conducive to the occurrence and development of rainfall,and the use of PUP to set a high function and distribution of the zero line can determine whether the weather transit system;" 100609 "during the short time,vertical integrated liquid water content(VIL)of the volatility of the performance is not obvious,the maximum intensity reflectivity is 70 dBz,the strong echo center height is relatively low,in the radar station near the analysis to close to the ground,the radial velocity map shows greater range in the near surface layer wind zone;analysis the" 100615 "process of discovery,with the typical characteristics of convective echo,the scale is not big,has the characteristics of obvious mesoscale convective systems,basic reflectivity intensity The center reached 55 dBz,from the analysis of circulation situation,the process is due to the cold air with low shear convergence layer,resulting in the strong echo band stays for a long time.The analysis of Wuzhou province "140329" process of discovery,Doppler radar echo reveals the occurrence and development of life history of convective clouds,wind profile data of the VWP wind field explains the strong convective clouds moving in the process of the development of the wind field information. |
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