Land cover change affects surface radiation budget and energy balance by chang- ing surface albedo and further impacts the regional and global climate. In this article, high spatial and temporal resolution satellite p...Land cover change affects surface radiation budget and energy balance by chang- ing surface albedo and further impacts the regional and global climate. In this article, high spatial and temporal resolution satellite products were used to analyze the driving mechanism for surface albedo change caused by land cover change during 1990-2010. In addition, the annual-scale radiative forcing caused by surface albedo changes in China＇s 50 ecological regions were calculated to reveal the biophysical mechanisms of land cover change affecting climate change at regional scale. Our results showed that the national land cover changes were mainly caused by land reclamation, grassland desertification and urbanization in past 20 years, which were almost induced by anthropogenic activities. Grassland and forest area decreased by 0.60% and 0.11%, respectively. The area of urban and farmland increased by 0.60% and 0.19%, respectively. The mean radiative forcing caused by land cover changes during 1990-2010 was 0.062 W/m2 in China, indicating a warming climate effect. However, spatial heterogeneity of radiative forcing was huge among different ecological regions. Farmland conversing to urban construction land, the main type of land cover change for the urban and suburban agricultural ecological region in Beijing-Tianjin-Tangshan region, caused an albedo reduction by 0.00456 and a maximum positive radiative forcing of 0.863 WIm2, which was presented as warming climate effects. Grassland and forest conversing to farmland, the main type of land cover change for the temperate humid agricultural and wetland ecological region in Sanjiang Plain, caused an albedo increase by 0.00152 and a maximum negative radiative forcing of 0.184 W/m2, implying cooling climate effects.展开更多
The complexity of inhomogeneous surface-atmosphere radiation transfer is one of the foremost problems in the field of atmospheric physics and atmospheric radiation. To date, the influence of surface properties on shor...The complexity of inhomogeneous surface-atmosphere radiation transfer is one of the foremost problems in the field of atmospheric physics and atmospheric radiation. To date, the influence of surface properties on shortwave radiation has not been well studied. The daily downward surface shortwave radiation of the latest FLASHFlux/CERES （Fast Longwave And Shortwave Fluxes_Time Interpolated and Spatially Averaged/Clouds and the Earth＇s Radiant Energy System） satellite data was evaluated against in situ data. The comparison indicated that the differences between the two data sets are unstable and large over rugged terrain compared with relatively flat terrain, and the mean absolute error of the satellite products reaches 31.4 W m-2 （12.3%） over rugged terrain. Based on the SSF （single satellite footprint）/CERES product, the influence of surface properties on the distribution of downward surface shortwave radiation （DSSR） was analyzed. The influence of surface properties on DSSR over the Tibetan Plateau is about twice as large as that in two other regions located at the same latitude （eastern China-western Pacific and subtropical North Pacific）. A simulation was carried out with the help of the I3RC （International Intercomparision of Three-Dimensional Radiation Code） Monte Carlo 3D radiative transfer community model. The results showed that DSSR increases as surface albedo increases. Moreover, the impact of surface albedo on DSSR is larger if the spatial distribution of clouds is more non-uniform. It is hoped that these results will contribute to the development of 3D radiative transfer models and the improvement of satellite inversion algorithms.展开更多
The method to estimate NSSR （net surface shortwave radiation） from LST （land surface temperature） in regional scale is discussed. First, an elliptical model between the time series of normalized LST and NSSR was d...The method to estimate NSSR （net surface shortwave radiation） from LST （land surface temperature） in regional scale is discussed. First, an elliptical model between the time series of normalized LST and NSSR was developed using the daily evolution of LST and NSSR. Second, time series of LST and NSSR were simulated by common land model （CoLM） and were proved to be of high accuracy. On the basis of these, a non-linear least square ellipse fitting using the genetic algorithm method was used to fit the normalized LST and NSSR. Finally, LST was inverted using MODIS （moderate resolution imaging spectroradiometer） data with the split-window algorithm, and the regional NSSR was then estimated with LST and an elliptical model. The validation result shows that the derived average NSSR of 50×50 pixels of MODIS data was quite close to the observed data, and the distribution was reasonable, which indicates that the proposed method was capable of estimating NSSR on a regional scale.展开更多
The one-dimensional Kraus- Turner mixed layer model improved by Liu is developed to consider the effect of salinity and the equa- tions of temperature and salinity under the mixed layer. On this basis, the processes o...The one-dimensional Kraus- Turner mixed layer model improved by Liu is developed to consider the effect of salinity and the equa- tions of temperature and salinity under the mixed layer. On this basis, the processes of growth and death of surface layer temperature inversion is numerically simulated under different environmental parameters. At the same time, the physical mechanism is preliminari- ly discussed combining the observations at the station of TOGA- COARE 0°N, 156°E. The results indicate that temperature inversion sensitively depends on the mixed layer depth, sea surface wind speed and solar shortwave radiation, etc., and appropriately meteoro- logical and hydrological conditions often lead to the similarly periodical occurrence of this inversion phenomenon.展开更多
In the context of 1985—1988 ERBE and 1984—1988 ISCCP planetary scale albedoes and total cloudiness in combination with Qinghai-Xizang actinometric measurements,investigation was performed of the climatic retrieval o...In the context of 1985—1988 ERBE and 1984—1988 ISCCP planetary scale albedoes and total cloudiness in combination with Qinghai-Xizang actinometric measurements,investigation was performed of the climatic retrieval of surface absorbed shortwave radiation(SASWR)in the research highland.Evidence suggests that the method has given higher fitting accuracy with mean error of 9.8 W m^(-2),whereupon was calculated the monthly mean SASWR flux density at the gridpoints of 2.5°×2.5°resolution over 25—40°N,75—95°E and 63 stations alongside a set of the distribution maps prepared for its basic features.展开更多
基金National Key Program for Developing Basic Science,No.2010CB950902Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA05090303
文摘Land cover change affects surface radiation budget and energy balance by chang- ing surface albedo and further impacts the regional and global climate. In this article, high spatial and temporal resolution satellite products were used to analyze the driving mechanism for surface albedo change caused by land cover change during 1990-2010. In addition, the annual-scale radiative forcing caused by surface albedo changes in China＇s 50 ecological regions were calculated to reveal the biophysical mechanisms of land cover change affecting climate change at regional scale. Our results showed that the national land cover changes were mainly caused by land reclamation, grassland desertification and urbanization in past 20 years, which were almost induced by anthropogenic activities. Grassland and forest area decreased by 0.60% and 0.11%, respectively. The area of urban and farmland increased by 0.60% and 0.19%, respectively. The mean radiative forcing caused by land cover changes during 1990-2010 was 0.062 W/m2 in China, indicating a warming climate effect. However, spatial heterogeneity of radiative forcing was huge among different ecological regions. Farmland conversing to urban construction land, the main type of land cover change for the urban and suburban agricultural ecological region in Beijing-Tianjin-Tangshan region, caused an albedo reduction by 0.00456 and a maximum positive radiative forcing of 0.863 WIm2, which was presented as warming climate effects. Grassland and forest conversing to farmland, the main type of land cover change for the temperate humid agricultural and wetland ecological region in Sanjiang Plain, caused an albedo increase by 0.00152 and a maximum negative radiative forcing of 0.184 W/m2, implying cooling climate effects.
基金supported by the National Natural Science Foundation of China (Grant No. 41127901)the Strategic Priority Research Program–Climate Change: Carbon Budget and Relevant Issues (Grant No. XDA05040300)
文摘The complexity of inhomogeneous surface-atmosphere radiation transfer is one of the foremost problems in the field of atmospheric physics and atmospheric radiation. To date, the influence of surface properties on shortwave radiation has not been well studied. The daily downward surface shortwave radiation of the latest FLASHFlux/CERES （Fast Longwave And Shortwave Fluxes_Time Interpolated and Spatially Averaged/Clouds and the Earth＇s Radiant Energy System） satellite data was evaluated against in situ data. The comparison indicated that the differences between the two data sets are unstable and large over rugged terrain compared with relatively flat terrain, and the mean absolute error of the satellite products reaches 31.4 W m-2 （12.3%） over rugged terrain. Based on the SSF （single satellite footprint）/CERES product, the influence of surface properties on the distribution of downward surface shortwave radiation （DSSR） was analyzed. The influence of surface properties on DSSR over the Tibetan Plateau is about twice as large as that in two other regions located at the same latitude （eastern China-western Pacific and subtropical North Pacific）. A simulation was carried out with the help of the I3RC （International Intercomparision of Three-Dimensional Radiation Code） Monte Carlo 3D radiative transfer community model. The results showed that DSSR increases as surface albedo increases. Moreover, the impact of surface albedo on DSSR is larger if the spatial distribution of clouds is more non-uniform. It is hoped that these results will contribute to the development of 3D radiative transfer models and the improvement of satellite inversion algorithms.
基金Supported by the Knowledge Innovation Programs of Chinese Academy of Sciences (XMXX280722)China International Science and Technology Cooperation Project (0819)+1 种基金National Program on Key Basic Research Project (2010CB428800)Wong K C Education Foundation, Hong Kong
文摘The method to estimate NSSR （net surface shortwave radiation） from LST （land surface temperature） in regional scale is discussed. First, an elliptical model between the time series of normalized LST and NSSR was developed using the daily evolution of LST and NSSR. Second, time series of LST and NSSR were simulated by common land model （CoLM） and were proved to be of high accuracy. On the basis of these, a non-linear least square ellipse fitting using the genetic algorithm method was used to fit the normalized LST and NSSR. Finally, LST was inverted using MODIS （moderate resolution imaging spectroradiometer） data with the split-window algorithm, and the regional NSSR was then estimated with LST and an elliptical model. The validation result shows that the derived average NSSR of 50×50 pixels of MODIS data was quite close to the observed data, and the distribution was reasonable, which indicates that the proposed method was capable of estimating NSSR on a regional scale.
文摘The one-dimensional Kraus- Turner mixed layer model improved by Liu is developed to consider the effect of salinity and the equa- tions of temperature and salinity under the mixed layer. On this basis, the processes of growth and death of surface layer temperature inversion is numerically simulated under different environmental parameters. At the same time, the physical mechanism is preliminari- ly discussed combining the observations at the station of TOGA- COARE 0°N, 156°E. The results indicate that temperature inversion sensitively depends on the mixed layer depth, sea surface wind speed and solar shortwave radiation, etc., and appropriately meteoro- logical and hydrological conditions often lead to the similarly periodical occurrence of this inversion phenomenon.
文摘In the context of 1985—1988 ERBE and 1984—1988 ISCCP planetary scale albedoes and total cloudiness in combination with Qinghai-Xizang actinometric measurements,investigation was performed of the climatic retrieval of surface absorbed shortwave radiation(SASWR)in the research highland.Evidence suggests that the method has given higher fitting accuracy with mean error of 9.8 W m^(-2),whereupon was calculated the monthly mean SASWR flux density at the gridpoints of 2.5°×2.5°resolution over 25—40°N,75—95°E and 63 stations alongside a set of the distribution maps prepared for its basic features.
