Since 1982,Landsat series of satellite sensors continuously acquired thermal infrared images of the Earth’s land surface.In this study,Landsat 5,7,and 8 land surface temperature(LST)products in the conterminous Unite...Since 1982,Landsat series of satellite sensors continuously acquired thermal infrared images of the Earth’s land surface.In this study,Landsat 5,7,and 8 land surface temperature(LST)products in the conterminous United States from 2009 to 2019 were validated using in situ measurements collected at 6 SURFRAD(Surface Radiation Budget Network)sites,6 ARM(Atmospheric Radiation Measurement)sites,and 9 NDBC(National Data Buoy Center)sites.The results indicate that a relatively consistent performance among Landsat 5,7,and 8 LST products is obtained for most sites due to the consistent LST retrieval algorithm in conjunction with the same atmospheric compensation and land surface emissivity(LSE)correction methods for Landsat 5,7,and 8 sensors.Large bias and root mean square error(RMSE)of Landsat LST product are obtained at some vegetated sites due to incorrect LSE estimation where LSE is invariant with the increasing of normalized difference vegetation index(NDVI).Except for the sites with incorrect LSE estimation,a mean bias(RMSE)of the differences between Landsat LST and in situ LST is 1.0 K(2.1 K)over snow-free land surfaces,−1.1 K(1.6 K)over snow surfaces,and−0.3 K(1.1 K)over water surfaces.展开更多
Passive microwave(PMW)observations from the Advanced Microwave Scanning Radiometer 2 provide a way to obtain cloudy land surface temperatures(LSTs).However,atmospheric corrections must be performed on cloudy LSTs due ...Passive microwave(PMW)observations from the Advanced Microwave Scanning Radiometer 2 provide a way to obtain cloudy land surface temperatures(LSTs).However,atmospheric corrections must be performed on cloudy LSTs due to the cloud effect at higher frequencies.In this paper,six reanalyzed profiles,including the fifth-generation European Centre for Medium-range Weather Forecasts Reanalysis(ERA5),Interim Reanalysis(ERA-Interim),Japanese 55-year Reanalysis Data(JRA-55),Modern-Era Retrospective analysis for Research and Application V2(MERRA2),National Centers for Environmental Prediction(NCEP)/Final Operational Global Analysis(FNL),and NCEP/Global Forecasting System(GFS),were compared with 2829 radiosonde profiles derived from the University of Wyoming.Then,their performances in correcting the atmospheric effects of LSTs at cloudy skies were investigated.Results showed that the ERA5 had the best accuracy in revealing the actual atmospheric conditions,and the RMSEs of transmittance,downward radiance,and upward radiance were about 0.007,2.01,and 1.89 K,respectively.The RMSEs between the estimated LSTs and referenced LSTs varied from 3.15 K of the ERA5 to 6.12 K of the NCEP/FNL,indicating the ERA5 can be recommended for the atmospheric correction of PMW-based LST retrievals.Additionally,transmittance accuracy plays an essential role in impacting the LST retrievals in any weather.展开更多
基金supported by the National Natural Science Foundation of China[grant numbers 41871275 and 41921001]by the Fundamental Research Funds for Central Non-profit Scientific Institution[grant number 1610132020044].
文摘Since 1982,Landsat series of satellite sensors continuously acquired thermal infrared images of the Earth’s land surface.In this study,Landsat 5,7,and 8 land surface temperature(LST)products in the conterminous United States from 2009 to 2019 were validated using in situ measurements collected at 6 SURFRAD(Surface Radiation Budget Network)sites,6 ARM(Atmospheric Radiation Measurement)sites,and 9 NDBC(National Data Buoy Center)sites.The results indicate that a relatively consistent performance among Landsat 5,7,and 8 LST products is obtained for most sites due to the consistent LST retrieval algorithm in conjunction with the same atmospheric compensation and land surface emissivity(LSE)correction methods for Landsat 5,7,and 8 sensors.Large bias and root mean square error(RMSE)of Landsat LST product are obtained at some vegetated sites due to incorrect LSE estimation where LSE is invariant with the increasing of normalized difference vegetation index(NDVI).Except for the sites with incorrect LSE estimation,a mean bias(RMSE)of the differences between Landsat LST and in situ LST is 1.0 K(2.1 K)over snow-free land surfaces,−1.1 K(1.6 K)over snow surfaces,and−0.3 K(1.1 K)over water surfaces.
基金supported by National Natural Science Foundation of China:[Grant Number 41871242,42001309].
文摘Passive microwave(PMW)observations from the Advanced Microwave Scanning Radiometer 2 provide a way to obtain cloudy land surface temperatures(LSTs).However,atmospheric corrections must be performed on cloudy LSTs due to the cloud effect at higher frequencies.In this paper,six reanalyzed profiles,including the fifth-generation European Centre for Medium-range Weather Forecasts Reanalysis(ERA5),Interim Reanalysis(ERA-Interim),Japanese 55-year Reanalysis Data(JRA-55),Modern-Era Retrospective analysis for Research and Application V2(MERRA2),National Centers for Environmental Prediction(NCEP)/Final Operational Global Analysis(FNL),and NCEP/Global Forecasting System(GFS),were compared with 2829 radiosonde profiles derived from the University of Wyoming.Then,their performances in correcting the atmospheric effects of LSTs at cloudy skies were investigated.Results showed that the ERA5 had the best accuracy in revealing the actual atmospheric conditions,and the RMSEs of transmittance,downward radiance,and upward radiance were about 0.007,2.01,and 1.89 K,respectively.The RMSEs between the estimated LSTs and referenced LSTs varied from 3.15 K of the ERA5 to 6.12 K of the NCEP/FNL,indicating the ERA5 can be recommended for the atmospheric correction of PMW-based LST retrievals.Additionally,transmittance accuracy plays an essential role in impacting the LST retrievals in any weather.
