Detection Performance of FY-4 A Lightning Mapping Imager Based on ADTD
To evaluate the lightning detection performance of the FY-4A,this paper proposes a matc-hing method based on the statistical characteristics of the satellite-ground lightning data.First,a larger time-space window is selected for satellite-ground data matching.Then,the time deviation and distance deviation of the matched data are statistically analyzed to determine the final suitable time-space window.By statistically analyzing the summer lightning data(from June to August)in 2020 from FY-4A and ground-based advanced direction and time-of-arrival detecting system(ADTD)in China,it is finally deter-mined that the time interval is 3.4 s and the spatial latitude and longitude interval is 0.6° as the time-space window for satellite-ground data consistency analysis.Based on this time-space window,a comparative a-nalysis of satellite-ground lightning data was carried out.The results show that the average time deviation of satellite-ground data is 1.3 s,and the average space deviation is 23.73 km.The detection efficiency of FY-4A lightning is 19%.It is found that the detection efficiency of FY-4A has obvious diurnal characteris-tics,with the detection efficiency during the day significantly lower than that at night.The average detec-tion efficiency at night is 31.1%,while during the day it is 7%.The detection efficiency is only 2.3%,the lowest from 12:00 to 14:00 during the day.The diurnal variation of the light radiation intensity of the FY-4A lightning data positively correlates with the change in the solar height angle.The light radiation intensity is the highest from 12:00 to 14:00 during the day,reaching 1 391 μJ/m2/sr,which is an order of magni-tude larger than that at night(124 μJ/m2/sr).This shows that only lightning with strong light radiation can be captured by the FY-4A lightning mapping imager(LMI)during the day,which further explains the reason for the low lightning detection efficiency during the day.
NETL
NSTL
万方数据
维普
