High spectral resolution(or hyperspectral)infrared(IR)sounders onboard low earth orbiting satellites provide high vertical resolution atmospheric information for numerical weather prediction(NWP)models.In contrast,ima...High spectral resolution(or hyperspectral)infrared(IR)sounders onboard low earth orbiting satellites provide high vertical resolution atmospheric information for numerical weather prediction(NWP)models.In contrast,imagers on geostationary(GEO)satellites provide high temporal and spatial resolution which are important for monitoring the moisture associated with severe weather systems,such as rapidly developing local severe storms(LSS).A hyperspectral IR sounder onboard a geostationary satellite would provide four-dimensional atmospheric temperature,moisture,and wind profiles that have both high vertical resolution and high temporal/spatial resolutions.In this work,the added-value from a GEO-hyperspectral IR sounder is studied and discussed using a hybrid Observing System Simulation Experiment(OSSE)method.A hybrid OSSE is distinctively different from the traditional OSSE in that,(a)only future sensors are simulated from the nature run and(b)the forecasts can be evaluated using real observations.This avoids simulating the complicated observation characteristics of the current systems(but not the new proposed system)and allows the impact to be assessed against real observations.The Cross-track Infrared Sounder(CrIS)full spectral resolution(FSR)is assumed to be onboard a GEO for the impact studies,and the GEO CrIS radiances are simulated from the ECMWF Reanalysis v5(ERA5)with the hyperspectral IR all-sky radiative transfer model(HIRTM).The simulated GEO CrIS radiances are validated and the hybrid OSSE system is verified before the impact assessment.Two LSS cases from 2018 and 2019 are selected to evaluate the value-added impacts from the GEO CrIS-FSR data.The impact studies show improved atmospheric temperature,moisture,and precipitation forecasts,along with some improvements in the wind forecasts.An added-value,consisting of an overall 5%Root Mean Square Error(RMSE)reduction,was found when a GEO CrIS-FSR is used in replacement of LEO ones indicat-ing the potential for applications of data from a GEO hyperspectral IR 展开更多
The HJ-1A satellite was successfully launched on September 6, 2008. The inclusion of a HyperSpectral Imager (HSI) as one of the payloads of the HJ-1A Satellite is a major milestone in the field of the remote sensing i...The HJ-1A satellite was successfully launched on September 6, 2008. The inclusion of a HyperSpectral Imager (HSI) as one of the payloads of the HJ-1A Satellite is a major milestone in the field of the remote sensing in China. It is also the first Fourier transform imaging spectrometer routinely used to acquire scientific data from a satellite orbiting Earth. This paper briefly introduces the basic imaging theories of the spatially modulated Fourier transform imaging spectrometer, and then discusses the theoretical analysis and algorithms of spectrum reconstruction. Results of the operational spectrum reconstruction for the raw data of the HJ-1A satellite Fourier transform HSI are presented. At present, the algorithms and processing flow have been used successfully in the Ground Data Processing System (GDPS) built by the China Center for Resource Satellite Data and Applications (CRESDA).展开更多
基金This work is supported by the NOAA GeoXO program(NA15NES4320001).
文摘High spectral resolution(or hyperspectral)infrared(IR)sounders onboard low earth orbiting satellites provide high vertical resolution atmospheric information for numerical weather prediction(NWP)models.In contrast,imagers on geostationary(GEO)satellites provide high temporal and spatial resolution which are important for monitoring the moisture associated with severe weather systems,such as rapidly developing local severe storms(LSS).A hyperspectral IR sounder onboard a geostationary satellite would provide four-dimensional atmospheric temperature,moisture,and wind profiles that have both high vertical resolution and high temporal/spatial resolutions.In this work,the added-value from a GEO-hyperspectral IR sounder is studied and discussed using a hybrid Observing System Simulation Experiment(OSSE)method.A hybrid OSSE is distinctively different from the traditional OSSE in that,(a)only future sensors are simulated from the nature run and(b)the forecasts can be evaluated using real observations.This avoids simulating the complicated observation characteristics of the current systems(but not the new proposed system)and allows the impact to be assessed against real observations.The Cross-track Infrared Sounder(CrIS)full spectral resolution(FSR)is assumed to be onboard a GEO for the impact studies,and the GEO CrIS radiances are simulated from the ECMWF Reanalysis v5(ERA5)with the hyperspectral IR all-sky radiative transfer model(HIRTM).The simulated GEO CrIS radiances are validated and the hybrid OSSE system is verified before the impact assessment.Two LSS cases from 2018 and 2019 are selected to evaluate the value-added impacts from the GEO CrIS-FSR data.The impact studies show improved atmospheric temperature,moisture,and precipitation forecasts,along with some improvements in the wind forecasts.An added-value,consisting of an overall 5%Root Mean Square Error(RMSE)reduction,was found when a GEO CrIS-FSR is used in replacement of LEO ones indicat-ing the potential for applications of data from a GEO hyperspectral IR
文摘针对两个特征波段组成的植被指数存在的饱和以及植物类型依赖问题,利用便携式地物光谱仪(analytical spectral devices,ASD)和哨兵2号多光谱卫星(Sentinel 2,S2)数据,使用改进的距离投影比值指数(improved distance projection ratio index,DPRI2)建立新叶片等效水厚度(leaf equivalent water thickness,LEWT)反演模型,进而反演冠层等效水厚度(canopy equivalent water thickness,CEWT)。研究表明:①R语言随机森林(random forest,RF)算法可减少特征波段选取过程中人为因素;②DPRI2结构简单,能充分反映特征波段之间角度、距离、投影三者组合关系,有利于提高LEWT、CEWT反演精度;③DPRI2不受植被类型限制,适用于具有多种植被类型的研究区CEWT反演。通过遥感手段监测CEWT,有利于探究植被在区域水文循环中的调控机制,以及科学评估区域水资源储量。
基金supported by the High Technology Research and Develop-ment Project (2007AA120306 and 2007AA120205)the National Natu-ral Science Foundation of China (40871163 and 40771150)
文摘The HJ-1A satellite was successfully launched on September 6, 2008. The inclusion of a HyperSpectral Imager (HSI) as one of the payloads of the HJ-1A Satellite is a major milestone in the field of the remote sensing in China. It is also the first Fourier transform imaging spectrometer routinely used to acquire scientific data from a satellite orbiting Earth. This paper briefly introduces the basic imaging theories of the spatially modulated Fourier transform imaging spectrometer, and then discusses the theoretical analysis and algorithms of spectrum reconstruction. Results of the operational spectrum reconstruction for the raw data of the HJ-1A satellite Fourier transform HSI are presented. At present, the algorithms and processing flow have been used successfully in the Ground Data Processing System (GDPS) built by the China Center for Resource Satellite Data and Applications (CRESDA).
