基于往返式平漂探空的FY-3D卫星反演温度检验

Inspection of FY-3D Satellite Temperature Data Based on Horizontal Drift Round-trip Sounding Data

往返式平漂探空观测(以下简称平漂探空)可实现对流层至平流层低层大气温度廓线垂直探测以及平流层低层内持续4 h的水平温度分布探测。该文介绍利用平漂探空试验数据对风云3号气象卫星D星(FY-3D)反演温度数据的检验评估算法,基于该算法和2021年3—9月长江中下游平漂探空试验数据完成对卫星反演大气温度数据的检验。结果显示:FY-3D卫星反演的温度数据准确度总体较高,与平漂探空上升段数据平均绝对偏差约为1.34℃,与下降段数据平均绝对偏差约为1.93℃;卫星反演的100 hPa以上和850 hPa以下温度误差分别偏大0.59℃和0.33℃;卫星反演平流层温度准确度低于温度廓线,平均绝对偏差约为3.92℃;与平漂探空数据相比,卫星大气温度廓线分辨率较低、趋势较平滑,无法显示大气温度垂直分布和平流层温度水平分布的细节特征。

The horizontal drift round-trip sounding observation is a new sounding technology developed by China Meteorological Administration.By releasing one sounding balloon with this technology,three sections of observations can be obtained,including two sections of vertical tropospheric sounding(ascending and descending)with an interval of about 6 hours and a 4-hour horizontal sounding within the stratosphere.This technology effectively makes up for the insufficiency of conventional soundings,improving the time and space resolution of radiosonde data at a lower cost.The detection system adopts Beidou radiosonde,which significantly improves the accuracy of sounding and wind measurements.In addition,the drift section of horizontal drift round-trip sounding observation fills the gap of the stratospheric temperature detection technology in China.Therefore,horizontal drift round-trip sounding data can be used to verify the temperature profile and stratosphere temperature data of meteorological satellite.Fengyun series meteorological satellites are widely used in China,supporting the meteorological forecast in the Eastern Hemisphere.Among Fengyun satellites in use,FY-3D has the longest years of service.To test the accuracy of FY-3D satellite temperature products,an algorithm is designed according to the characteristics of the horizontal drift round-trip sounding data and satellite data,and the temporal and spatial thresholds are calculated.Based on this algorithm,FY-3D satellite retrieved atmospheric temperature data are verified using the horizontal drift round-trip sounding data in the middle and lower reaches of the Yangtze from March to September in 2021.It can be concluded from the inspection results that the temperature data of FY-3D satellite has a high accuracy,with an average absolute deviation of about 1.34℃from the data of ascending section and 1.9℃from the data of descending section.Above 100 hPa and below850 hPa,the temperature errors of satellite data are 0.59℃and 0.33℃larger,respectively.The average absolute deviation of the stratosphere is about 3.92℃,which is slightly larger than the ascending section and descending section.Compared with the sounding profile,the satellite temperature profile has lower vertical resolution and smoother trend,so it cannot show more details of atmospheric vertical variation.