Based on spatial interpolation rainfall of the ground gauge measurement,we proposed a method to comprehensively evaluate and compare the accuracy of satellite rainfall estimates (SREs) at three spatial scales:0.25...Based on spatial interpolation rainfall of the ground gauge measurement,we proposed a method to comprehensively evaluate and compare the accuracy of satellite rainfall estimates (SREs) at three spatial scales:0.25°×0.25° grid scale,sub-catchment scale and the whole basin scale.Using this method,we evaluated the accuracy of six high-resolution monthly SREs (TRMM 3B42 V6,3B42RT V6,CMORPH,GSMaP MWR+,GSMaP MVK+ and PERSIANN) and revealed the spatio-temporal variation of the SRE accuracy based on spatial interpolated rainfall from a dense network of 325 gauges during 2003-2009 over the Ganjiang River Basin in the Southeast China.The results showed that ground gauge-calibrated 3B42 had the highest accuracy with slight overestimation,whereas the other five uncalibrated SREs had severe underestimation.The accuracy of the six SREs in wet seasons was remarkably higher than that in the dry seasons.When the time scale was expanded,the accuracy of SRE,particularly 3B42,increased.Furthermore,the accuracy of SREs was relatively low in the western mountains and northern piedmont areas,while it was relatively high in the central and southeastern hills and basins of the Ganjiang River Basin.When the space scale was expanded,the accuracy of the six SREs gradually increased.This study provided an example for of SRE accuracy validation in other regions,and a direct basis for further study of SRE-based hydrological process.展开更多
GeoEye-1是2008年9月发射的一颗迄今技术最先进、分辨率最高的商业对地成像卫星。本文介绍了针对GeoEye-1卫星遥感影像,采用基于PCI Geomatica 10.2软件的Pansharpen影像融合方法与RPC(Compute From Gcps)正射纠正方法,获得高精度的真彩...GeoEye-1是2008年9月发射的一颗迄今技术最先进、分辨率最高的商业对地成像卫星。本文介绍了针对GeoEye-1卫星遥感影像,采用基于PCI Geomatica 10.2软件的Pansharpen影像融合方法与RPC(Compute From Gcps)正射纠正方法,获得高精度的真彩色GeoEye-1正射影像。展开更多
随着TerraSAR-X,Cosmo-SkyMed和Radarsat-2这三颗高分辨率SAR卫星的成功发射,国内越来越多的用户开始通过商业渠道或通过参与SAR数据的应用示范项目免费获取到这三颗卫星的SAR数据。要很好地应用SAR数据必须首先解决其地理编码或几何校...随着TerraSAR-X,Cosmo-SkyMed和Radarsat-2这三颗高分辨率SAR卫星的成功发射,国内越来越多的用户开始通过商业渠道或通过参与SAR数据的应用示范项目免费获取到这三颗卫星的SAR数据。要很好地应用SAR数据必须首先解决其地理编码或几何校正问题,而该问题的核心是解决SAR定位模型的建立和解算方法,在此基础上就可以实现SAR影像的地球椭球校正地理编码(Geocoding of Ellipsoid Correction,GEC)处理,增强地球椭球地理编码(Enhanced Elliposid Correction,EEC)和地形校正地理编码(Geocoding of Terrain Correc-tion,GTC)或正射校正。本文研究并实现了这三颗高分辨率SAR数据的定位模型构建方法,并对GEC效果进行了评价。结果表明本文发展的定位模型构建方法是正确的,为实现这三颗高分辨率卫星SAR数据的EEC和GTC处理奠定了基础。展开更多
Coarse-resolution satellite albedo products are important for climate change and energy balance research because of their capability to characterize the spatiotemporal patterns of land surface parameters at both the r...Coarse-resolution satellite albedo products are important for climate change and energy balance research because of their capability to characterize the spatiotemporal patterns of land surface parameters at both the regional and global scales. The accuracy of coarse-resolution products is usually assessed via comparison with in situ measurements. The key issue in the comparison of remote sensing observations with in situ measurements is scaling and uncertainty. This paper presents a strategy for validating 1-km-resolution remote sensing albedo products using field measurements and high-resolution remote sensing observations. Field measurements were collected to calibrate the high-resolution(30 m) albedo products derived from HJ-1a/b images. Then, the calibrated high-resolution albedo maps were resampled(i.e., upscaled) to assess the accuracy of the coarse-resolution albedo products. The samples of field measurements and high-resolution pixels are based on an uncertainty analysis. Two types of coarse-resolution albedo datasets, from global land surface satellite(GLASS) and moderate-resolution imaging spectroradiometer(MODIS), are validated over the middle reaches of the Heihe River in China. The results indicate that the upscaled HJ(Huan Jing means environment in Chinese and this refers to a satellite constellation designed for environment and disaster monitoring by China) albedo, which was calibrated using field measurements, can provide accurate reference values for validating coarse-resolution satellite albedo products. However, the uncertainties in the upscaled HJ albedo should be estimated, and pixels with large uncertainties should be excluded from the validation process.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 51109136)the Commonweal Science Research Project of Ministry of Water Resources of China (Grant Nos. 201001002,201101004)the Science and Technology Development Fund,Ministry of Water Resources of China (Grant No. TG1109)
文摘Based on spatial interpolation rainfall of the ground gauge measurement,we proposed a method to comprehensively evaluate and compare the accuracy of satellite rainfall estimates (SREs) at three spatial scales:0.25°×0.25° grid scale,sub-catchment scale and the whole basin scale.Using this method,we evaluated the accuracy of six high-resolution monthly SREs (TRMM 3B42 V6,3B42RT V6,CMORPH,GSMaP MWR+,GSMaP MVK+ and PERSIANN) and revealed the spatio-temporal variation of the SRE accuracy based on spatial interpolated rainfall from a dense network of 325 gauges during 2003-2009 over the Ganjiang River Basin in the Southeast China.The results showed that ground gauge-calibrated 3B42 had the highest accuracy with slight overestimation,whereas the other five uncalibrated SREs had severe underestimation.The accuracy of the six SREs in wet seasons was remarkably higher than that in the dry seasons.When the time scale was expanded,the accuracy of SRE,particularly 3B42,increased.Furthermore,the accuracy of SREs was relatively low in the western mountains and northern piedmont areas,while it was relatively high in the central and southeastern hills and basins of the Ganjiang River Basin.When the space scale was expanded,the accuracy of the six SREs gradually increased.This study provided an example for of SRE accuracy validation in other regions,and a direct basis for further study of SRE-based hydrological process.
文摘GeoEye-1是2008年9月发射的一颗迄今技术最先进、分辨率最高的商业对地成像卫星。本文介绍了针对GeoEye-1卫星遥感影像,采用基于PCI Geomatica 10.2软件的Pansharpen影像融合方法与RPC(Compute From Gcps)正射纠正方法,获得高精度的真彩色GeoEye-1正射影像。
文摘随着TerraSAR-X,Cosmo-SkyMed和Radarsat-2这三颗高分辨率SAR卫星的成功发射,国内越来越多的用户开始通过商业渠道或通过参与SAR数据的应用示范项目免费获取到这三颗卫星的SAR数据。要很好地应用SAR数据必须首先解决其地理编码或几何校正问题,而该问题的核心是解决SAR定位模型的建立和解算方法,在此基础上就可以实现SAR影像的地球椭球校正地理编码(Geocoding of Ellipsoid Correction,GEC)处理,增强地球椭球地理编码(Enhanced Elliposid Correction,EEC)和地形校正地理编码(Geocoding of Terrain Correc-tion,GTC)或正射校正。本文研究并实现了这三颗高分辨率SAR数据的定位模型构建方法,并对GEC效果进行了评价。结果表明本文发展的定位模型构建方法是正确的,为实现这三颗高分辨率卫星SAR数据的EEC和GTC处理奠定了基础。
基金sponsored by the National Basic Research Program of China(Grant No.2013CB733401)the National High Technology Research and Development Program of China(Grant No.2012AA12A300)the National Natural Science Foundation of China(Grant Nos.41273168,41331171)
文摘Coarse-resolution satellite albedo products are important for climate change and energy balance research because of their capability to characterize the spatiotemporal patterns of land surface parameters at both the regional and global scales. The accuracy of coarse-resolution products is usually assessed via comparison with in situ measurements. The key issue in the comparison of remote sensing observations with in situ measurements is scaling and uncertainty. This paper presents a strategy for validating 1-km-resolution remote sensing albedo products using field measurements and high-resolution remote sensing observations. Field measurements were collected to calibrate the high-resolution(30 m) albedo products derived from HJ-1a/b images. Then, the calibrated high-resolution albedo maps were resampled(i.e., upscaled) to assess the accuracy of the coarse-resolution albedo products. The samples of field measurements and high-resolution pixels are based on an uncertainty analysis. Two types of coarse-resolution albedo datasets, from global land surface satellite(GLASS) and moderate-resolution imaging spectroradiometer(MODIS), are validated over the middle reaches of the Heihe River in China. The results indicate that the upscaled HJ(Huan Jing means environment in Chinese and this refers to a satellite constellation designed for environment and disaster monitoring by China) albedo, which was calibrated using field measurements, can provide accurate reference values for validating coarse-resolution satellite albedo products. However, the uncertainties in the upscaled HJ albedo should be estimated, and pixels with large uncertainties should be excluded from the validation process.
