Environment and disaster monitoring and forecasting small satellite constellation A and B satellites(HJ-1-A,B) are called "environment and disaster reduction satellites A and B" for short.The constellation a...Environment and disaster monitoring and forecasting small satellite constellation A and B satellites(HJ-1-A,B) are called "environment and disaster reduction satellites A and B" for short.The constellation adopts a 10:30LT sun-synchronous circular orbit,with orbit altitude of 649km.HJ1-A and HJ-1-B are distributed with a phase difference of 180° in the same orbital plane,so as to enhance the time resolution of earth observation.The satellites have orbit maintenance capability,the lifetime is 3 years.Both satellites adopt CAST968 platforms.Two wide-coverage multispectral CCD cameras with resolution 30m and width 700km,a super-spectral imager with resolution 100m and width 50km as well as a data transmission subsystem of 120Mbit/s are deployed on HJ-1-A,which also carries Ka communication testing equipment of Thailand.HJ-1-B has two wide-coverage multispectral CCD cameras(the same as satellite A),one infrared camera with resolution 150m and width 720km and a data transmission subsystem of 60Mbit/s.The coverage period of the wide-coverage multispectral CCD camera is 48 hours.The revisit period of super-spectral imager is 96 hours and the coverage period ofinfrared camera is 96 hours.展开更多
The ecosystem in northeastern China and the Russian Far East is a hotspot of scientific research into the global carbon balance.Forest aboveground biomass(AGB) is an important component in the land surface carbon cycl...The ecosystem in northeastern China and the Russian Far East is a hotspot of scientific research into the global carbon balance.Forest aboveground biomass(AGB) is an important component in the land surface carbon cycle.In this study,using forest inventory data and forest distribution data,the AGB was estimated for forest in Daxinganlin in northeastern China by combining charge-coupled device(CCD) data from the Small Satellite for Disaster and Environment Monitoring and Forecast(HJ-1) and Geoscience Laser Altimeter System(GLAS) waveform data from the Ice,Cloud and land Elevation Satellite(ICESat).The forest AGB prediction models were separately developed for different forest types in the research area at GLAS footprint level from GLAS waveform parameters and field survey plot biomass in the Changqing(CQ) Forest Center,which was calculated from forest inventory data.The resulted statistical regression models have a R2=0.68 for conifer and R2=0.71 for broadleaf forests.These models were used to estimate biomass for all GLAS footprints of forest located in the study area.All GLAS footprint biomass coupled with various spectral reflectivity parameters and vegetation indices derived from HJ-1 satellite CCD data were used in multiple regression analyses to establish biomass prediction models(R2=0.55 and R2=0.52 for needle and broadleaf respectively).Then the models were used to produce a forest AGB map for the whole study area using the HJ-1 data.Biomass data obtained from forest inventory data of the Zhuanglin(ZL) Forest Center were used as independent field measurements to validate the AGB estimated from HJ-1 CCD data(R2=0.71).About 80% of biomass samples had an error less than 20 t ha-1,and the mean error of all validation samples is 5.74 t ha-1.The pixel-level biomass map was then stratified into different biomass levels to illustrate the AGB spatial distribution pattern in this area.It was found that HJ-1 wide-swath data and GLAS waveform data can be combined to estimate forest biomass with good precision,and the biomass data can be used as input data for future carbon budget analysis.展开更多
文摘Environment and disaster monitoring and forecasting small satellite constellation A and B satellites(HJ-1-A,B) are called "environment and disaster reduction satellites A and B" for short.The constellation adopts a 10:30LT sun-synchronous circular orbit,with orbit altitude of 649km.HJ1-A and HJ-1-B are distributed with a phase difference of 180° in the same orbital plane,so as to enhance the time resolution of earth observation.The satellites have orbit maintenance capability,the lifetime is 3 years.Both satellites adopt CAST968 platforms.Two wide-coverage multispectral CCD cameras with resolution 30m and width 700km,a super-spectral imager with resolution 100m and width 50km as well as a data transmission subsystem of 120Mbit/s are deployed on HJ-1-A,which also carries Ka communication testing equipment of Thailand.HJ-1-B has two wide-coverage multispectral CCD cameras(the same as satellite A),one infrared camera with resolution 150m and width 720km and a data transmission subsystem of 60Mbit/s.The coverage period of the wide-coverage multispectral CCD camera is 48 hours.The revisit period of super-spectral imager is 96 hours and the coverage period ofinfrared camera is 96 hours.
基金supported by National Basic Research Program of China (Grant No.2007CB714404)National Natural Science Foundation of China (Grant Nos.40701124,40930530)
文摘The ecosystem in northeastern China and the Russian Far East is a hotspot of scientific research into the global carbon balance.Forest aboveground biomass(AGB) is an important component in the land surface carbon cycle.In this study,using forest inventory data and forest distribution data,the AGB was estimated for forest in Daxinganlin in northeastern China by combining charge-coupled device(CCD) data from the Small Satellite for Disaster and Environment Monitoring and Forecast(HJ-1) and Geoscience Laser Altimeter System(GLAS) waveform data from the Ice,Cloud and land Elevation Satellite(ICESat).The forest AGB prediction models were separately developed for different forest types in the research area at GLAS footprint level from GLAS waveform parameters and field survey plot biomass in the Changqing(CQ) Forest Center,which was calculated from forest inventory data.The resulted statistical regression models have a R2=0.68 for conifer and R2=0.71 for broadleaf forests.These models were used to estimate biomass for all GLAS footprints of forest located in the study area.All GLAS footprint biomass coupled with various spectral reflectivity parameters and vegetation indices derived from HJ-1 satellite CCD data were used in multiple regression analyses to establish biomass prediction models(R2=0.55 and R2=0.52 for needle and broadleaf respectively).Then the models were used to produce a forest AGB map for the whole study area using the HJ-1 data.Biomass data obtained from forest inventory data of the Zhuanglin(ZL) Forest Center were used as independent field measurements to validate the AGB estimated from HJ-1 CCD data(R2=0.71).About 80% of biomass samples had an error less than 20 t ha-1,and the mean error of all validation samples is 5.74 t ha-1.The pixel-level biomass map was then stratified into different biomass levels to illustrate the AGB spatial distribution pattern in this area.It was found that HJ-1 wide-swath data and GLAS waveform data can be combined to estimate forest biomass with good precision,and the biomass data can be used as input data for future carbon budget analysis.
