Earth surface longwave radiation(SLR),including downward(DLR),upward(ULR),and net longwave radiation(NLR),significantly impacts the surface radiation budget and global climate evolution.However,the spatiotemporal vari...Earth surface longwave radiation(SLR),including downward(DLR),upward(ULR),and net longwave radiation(NLR),significantly impacts the surface radiation budget and global climate evolution.However,the spatiotemporal variation in SLR remains poorly understood.In this study,three satellite products(GLASS-MODIS V40,GLASS-AVHRR,and CERES-SYN)and three reanalysis datasets(ERA5,MERRA-2,and GLDAS)were validated using ground measurements from 288 sites at seven observation networks.The mean biases and root mean square errors of the monthly DLR(ULR,NLR)estimates from the six products were-6.36(-3.56,-2.86)Wm^(-2) and 16.63(14.33,13.38)Wm^(-2),respectively.Large differences in the spatial distribution of the SLR were mainly observed at high-latitude,high-altitude and desert/barren-covered regions.Large interannual variability was detected at high latitudes.GLASS-AVHRR and ERA5 better captured the long-term variability in DLR and ULR,whereas GLASS-AVHRR and MERRA-2 better detected trends in NLR.An increasing trend in DLR and ULR was observed between 1982 and 2015,followed by a decreasing trend from 2016 to 2021;the NLR flux did not exhibit a significant trend.Overall,the GLASS-AVHRR and ERA5 SLR estimates were more accurate and stable than those of the,other products in accuracy,spatiotemporal distribution,and trend analysis.展开更多
基金supported by the Open Research Program of the International Research Center of Big Data for Sus-tainable Development Goals,Grant No.CBAS2022ORP01the National Natural Science Foundation of China under Grant[number 42090011].
文摘Earth surface longwave radiation(SLR),including downward(DLR),upward(ULR),and net longwave radiation(NLR),significantly impacts the surface radiation budget and global climate evolution.However,the spatiotemporal variation in SLR remains poorly understood.In this study,three satellite products(GLASS-MODIS V40,GLASS-AVHRR,and CERES-SYN)and three reanalysis datasets(ERA5,MERRA-2,and GLDAS)were validated using ground measurements from 288 sites at seven observation networks.The mean biases and root mean square errors of the monthly DLR(ULR,NLR)estimates from the six products were-6.36(-3.56,-2.86)Wm^(-2) and 16.63(14.33,13.38)Wm^(-2),respectively.Large differences in the spatial distribution of the SLR were mainly observed at high-latitude,high-altitude and desert/barren-covered regions.Large interannual variability was detected at high latitudes.GLASS-AVHRR and ERA5 better captured the long-term variability in DLR and ULR,whereas GLASS-AVHRR and MERRA-2 better detected trends in NLR.An increasing trend in DLR and ULR was observed between 1982 and 2015,followed by a decreasing trend from 2016 to 2021;the NLR flux did not exhibit a significant trend.Overall,the GLASS-AVHRR and ERA5 SLR estimates were more accurate and stable than those of the,other products in accuracy,spatiotemporal distribution,and trend analysis.
