First satellite observation of total column water vapor from the Chinese Environmental Trace Gases Monitoring Instrument  

作　　者：Ran ZHAO Chengxin ZHANG Wenjing SU Jin YE Ziwei LI Cheng LIU 

机构地区：[1]School of Environmental Science and Optoelectronic Technology,University of Science and Technology of China,Hefei,230026,China [2]Department of Precision Machinery and Precision Instrumentation,University of Science and Technology of China,Hefei,230026,China [3]Department of Environmental Science and Engineering,University of Science and Technology of China,Hefei,230026,China [4]Key Laboratory of Environmental Optics and Technology,Anhui Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Hefei,230031,China [5]Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes,University of Science and Technology of China,Hefei,230026,China

出　　处：《Science China Earth Sciences》2025年第4期977-997,共21页中国科学(地球科学英文版)

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.42225504,42375120&62305322);the National Key Research and Development Program of China(Grant No.2022YFC3700100);the Major Project of High Resolution Earth Observation System(Grant No.30-Y60B01-9003-22/23);the Fundamental Research Funds for the Central Universities(Grant Nos.YD2090002021&WK2090000038)。

摘　　要：Atmospheric water vapor is a critical component of the Earth's water cycle and has significant impacts on weather,climate,and atmospheric chemistry.However,deficiencies remain in the coverage and accuracy of water vapor monitoring.In this study,we first retrieved the total column water vapor(TCWV)in the visible blue spectral band from two Chinese satellite UV-Vis spectrometers,the Environmental Trace Gases Monitoring Instruments(EMIs),which are onboard the Chinese GaoFen-5(GF-5,since May 2018)and GaoFen-5B(GF-5B,since September 2021)satellites.Nevertheless,limited by factors such as the relatively lower spectral signal-to-noise ratio and weak absorption of water vapor,the accurate retrieval of TCWV from the EMI spectrum is rather challenging.Therefore,we improved the baseline TCWV retrieval based on the differential optical absorption technique,including the re-calibration of the on-orbit spectra,optimization of the spectral fitting,and bias correction in the fitted result.Sensitivity tests show that the mean retrieval TCWV error of the EMI decreased by 1.47 kg m-2compared to that using uncalibrated spectra.The improved spectral fitting significantly reduced the relative uncertainty of the water vapor slant column densities(SCD)by 13.42%,and increased the number of successful fits by 11.64%.The improved EMI TCWV retrieval results from both the GF-5 and GF-5B satellites show a trend consistent with the TROPOspheric Monitoring Instrument(TROPOMI)satellite observations,with a correlation coefficient(R)of 0.98 and a mean bias of 1.04 kg m-2(6.88%).Ground-based validations showed that the correlation between the EMI TCWV retrievals from the GF-5B satellite(R=0.91)and sun photometer measurements was significantly higher than that from the GF-5 satellite(R=0.87),which may have been due to the improved performance of the EMI instrument on the GF-5B satellite.Finally,we showed that an intense atmospheric river event could be successfully captured by EMI TCWV measurements,which could support the monitoring and forecasting

关 键 词：Water vapor UV-Vis sensor Trace gas Remote sensing Atmospheric composition 

分 类 号：P407.5[天文地球—大气科学及气象学]