The high spatial resolution and temporal observation frequency of HJ-1/CCD make it suitable for aerosol monitoring.However,because of the lack of a shortwave infrared band,it is difficult to use HJ-1/CCD imagery to re...The high spatial resolution and temporal observation frequency of HJ-1/CCD make it suitable for aerosol monitoring.However,because of the lack of a shortwave infrared band,it is difficult to use HJ-1/CCD imagery to retrieve aerosol optical depth(AOD).We developed a new algorithm for HJ-1/CCD AOD retrieval by introducing MODIS surface reflectance outputs(MOD09) as support.In this algorithm HJ-1/CCD blue band surface reflectance was retrieved through MOD09 blue band surface reflectance by band matching of the two sensors.AOD at 550 nm was then generated through a pre-calculated look-up table for HJ-1/CCD.Eighteen HJ-1/CCD images covering the Jing-Jin-Tang(Beijing-Tianjin-Tangshan) region were used to retrieve AOD using the new algorithm,and the AODs were then validated using AERONET ground measurements in Beijing and Xianghe.The validation shows that compared with AERONET ground measurements,27/29 AODs have error less than 0.1 in absolute value.展开更多
It is very difficult to have remote sensing data with both high spatial resolution and high temporal frequency; thus, two categories of land-use mapping methodology have been developed separately for coarser resolutio...It is very difficult to have remote sensing data with both high spatial resolution and high temporal frequency; thus, two categories of land-use mapping methodology have been developed separately for coarser resolution and finer resolution data. The first category uses time series of data to retrieve the variation of land surface for classification, which are usually used for coarser resolution data with high temporal frequency. The second category uses fine spatial resolution data to classify different land surface. With the launch of Chinese satellite constellation HJ-1in 2008, four 30 m spatial resolution CCDs with about 360 km coverage for each one onboard two satellites made a revisit period of two days, which brought a new type of data with both high spatial resolution and high temporal frequency. Therefore, by taking the spatiotemporal advantage of HJ-1/CCD data we propose a new method for finer resolution land cover mapping using the time series HJ-1/CCD data, which can greatly improve the land cover mapping accuracy. In our two study areas, the very high resolution remote sensing data within Google Earth are used to validate the land cover mapping results, which shows a very high mapping accuracy of 95.76% and 83.78% and a high Kappa coefficient of 0.9423 and 0.8165 in the Dahuofang area of Liaoning Province and the Heiquan area of Gansu Province respectively.展开更多
基金supported by National Natural Science Foundation of China (Grant No.40701112)National Key Technology R & D Program of China (Grant No.2008BAC34B03)National High-tech R & D Program of China (Grant No.2009AA12Z147)
文摘The high spatial resolution and temporal observation frequency of HJ-1/CCD make it suitable for aerosol monitoring.However,because of the lack of a shortwave infrared band,it is difficult to use HJ-1/CCD imagery to retrieve aerosol optical depth(AOD).We developed a new algorithm for HJ-1/CCD AOD retrieval by introducing MODIS surface reflectance outputs(MOD09) as support.In this algorithm HJ-1/CCD blue band surface reflectance was retrieved through MOD09 blue band surface reflectance by band matching of the two sensors.AOD at 550 nm was then generated through a pre-calculated look-up table for HJ-1/CCD.Eighteen HJ-1/CCD images covering the Jing-Jin-Tang(Beijing-Tianjin-Tangshan) region were used to retrieve AOD using the new algorithm,and the AODs were then validated using AERONET ground measurements in Beijing and Xianghe.The validation shows that compared with AERONET ground measurements,27/29 AODs have error less than 0.1 in absolute value.
基金supported by the Chinese Academy of Sciences Action Plan for West Development Project (Grant No. KZCX2-XB3-15)the National High-tech R&D Program of China (Grant No. 2012AA12A304)
文摘It is very difficult to have remote sensing data with both high spatial resolution and high temporal frequency; thus, two categories of land-use mapping methodology have been developed separately for coarser resolution and finer resolution data. The first category uses time series of data to retrieve the variation of land surface for classification, which are usually used for coarser resolution data with high temporal frequency. The second category uses fine spatial resolution data to classify different land surface. With the launch of Chinese satellite constellation HJ-1in 2008, four 30 m spatial resolution CCDs with about 360 km coverage for each one onboard two satellites made a revisit period of two days, which brought a new type of data with both high spatial resolution and high temporal frequency. Therefore, by taking the spatiotemporal advantage of HJ-1/CCD data we propose a new method for finer resolution land cover mapping using the time series HJ-1/CCD data, which can greatly improve the land cover mapping accuracy. In our two study areas, the very high resolution remote sensing data within Google Earth are used to validate the land cover mapping results, which shows a very high mapping accuracy of 95.76% and 83.78% and a high Kappa coefficient of 0.9423 and 0.8165 in the Dahuofang area of Liaoning Province and the Heiquan area of Gansu Province respectively.
