Sensitivity Analysis Of Initial Error Of Rainstorm Forecast In Southern Monsoon Region

This paper selects 34 rainstorm cases in the south monsoon region in China from 2008 to2020,and compares the results of NCEP?FNL and TIGGE?EC for the rainstorm process to determine the source of the rainstorm forecast error in the southern monsoon region.On this basis,based on the WRF model,the forecast results obtained from the two initial fields NCEP?FNL and TIGGE?EC(WRF?FNL and WRF?EC respectively)are used to explore the influence of the initial error on the rainstorm forecasting techniques in the southern monsoon region,and in-depth study of the south monsoon region in China since 2008 The main conclusions are as follows:(1)In the "2015.5.16" typical heavy rain event,the WRF?EC forecast result is significantly better than the phase WRF?FNL result.The wet energy is further introduced to analyze the difference of the initial field,and it is found that the main source area of the initial error is from the Beibu Gulf of the South China Sea to the southwest of Guangxi.The main source variables are the disturbance temperature field and the humidity field.Using TIGGE?EC to replace the initial field of meteorological elements in the FNL in the sensitive area has a significant effect on improving the prediction effect of the precipitation process.(2)Aiming at the extreme events of the long plum flood season in the Jianghuai area in2020,we selected 11 related heavy rain events in the Jianghuai monsoon area.The analysis found that the initial field obtained by TIGGE?EC was also significant in the simulation of the WRF heavy rain process due to FNL,indicating that the initial error is An important source of forecast errors in this process.Analyzing the large-value area(sensitive area)and main influencing factors(sensitive variables)of the disturbance humidity energy,it is found that the water vapor change in the western inland,that is,the upstream area,is an important source of forecast error for the rainstorm in the Jianghuai monsoon area,and its accurate description can be helpful for this The forecast effect of the secondary process.(3)Summarize 19 torrential rain events in the South China monsoon region from 2008 to2019.It is found that there is a certain law in the distribution of the large value area of the disturbance wet energy of the initial error in the South China monsoon region,that is,the large value center of the disturbance wet energy and the large value center of the precipitation area It is about 5 longitudes apart,and is roughly concentrated in the range of 4°×4°.On this basis,using 700 h Pa guided airflow combined with the location of the precipitation area,a guided airflow method for objective identification of sensitive areas is proposed,so as to realize the objective identification of areas with large values of moisture energy disturbances.