Application Of The FY-4 Data Products In Sever Convection Monitoring

Severe convective weather occurs in mesoscale weather systems,mainly ? mesoscales of 200km-20 km and ? mesoscales of 20km-2km.It occurs suddenly and its life history is short,so it is difficult to use conventional meteorological observation ways to effectively monitor and track.China's FY-4 geostationary satellite is equipped with the lightning imager(LMI)for the first time and the world's first geo interferometric infrared sounder(GIRRS).It provides a lot of new detection information.At present,there are urgent business needs in practical application of these new information.And the problems about the application on short-term forecasting of sever convective weather in theories and algorithm development need to be solved.Therefore,this article uses the FY-4 bright temperature data and GIRRS AVP products of a total of 48 times during April 18,2019,from 03:00 to 15:00(UTC)and sounding station profile data,and also takes the rainstorm in Xiamen on May 7,2018 as a case study,using satellite cloud images during the rain,as well as LMI lightning products,ground lightning monitoring data,automatic weather station precipitation data,studied the application of the LMIE and AVP products from FY-4 on sever convection monitoring.The study found that:1.The fusion of FY-4 lightning data and ground-based lightning data effectively reduces the incompleteness,uncertainty and errors of the single data source.It improves the temporal and spatial resolution of lightning data,and enhances capability of dynamic lightning monitoring.And the fusion improves the overall image quality and comprehensive analysis accuracy.2.The distribution of lightning is consistent with the position of the convection(TBB?265 K).Its movement path is consistent with the movement path of the convection,and the lightning-strength center is ahead of the convection's center about 15 minutes.High-density areas of lightning appear in areas with sever convection(TBB?221K)and large temperature gradients.There is a positive correlation between lightning intensity and convection intensity.3.Although there is a large number of missing measurements of temperature and humidity profiles in AVP products,but the AVP products still has a much higher temporal and spatial resolution.Therefore,it still has a very high application advantage in monitoring and analyzing the vertical parameter changes of continuous sever convection.In general,humidity profiles have more available data than temperature profiles,but humidity profile has a larger number of intermediate faults than temperature profile.The quality of temperature profile in available data is very good,while that of humidity profile is poor.It can be seen that temperature profile has an extremely high application advantage in qualitative and quantitative analysis of vertical parameters of sever convection,but the feasibility of using humidity profile data to get quantitative analysis of that is poor.4.AVP profile has a good performance in detection of atmospheric vertical stratification.There will be a significant turning in the temperature profile when inversion occurs.But generally,the AVP profile is smoother than the sounding profile,which is more obvious in the humidity profile.5.In the ?-mesoscale MCS,water vapor is concentrated around 700 h Pa,and the water vapor begins to condense at 700 h Pa.The troposphere top is around 100 h Pa.The transition of MCS temperature profile near the troposphere top in the high latitudes is gentle.