This study conducted computer-aided image analysis of land use and land cover in Xilin River Basin, Inner Mongolia, using 4 sets of Landsat TM/ETM+ images acquired on July 31, 1987, August 11, 1991, Sep...This study conducted computer-aided image analysis of land use and land cover in Xilin River Basin, Inner Mongolia, using 4 sets of Landsat TM/ETM+ images acquired on July 31, 1987, August 11, 1991, September 27, 1997 and May 23, 2000, respectively. Primarily, 17 sub-class land cover types were recognized, including nine grassland types at community level: F.sibiricum steppe, S.baicalensis steppe, A.chinensis+ forbs steppe, A.chinensis+ bunchgrass steppe, A.chinensis+ Ar.frigida steppe, S.grandis+ A.chinensis steppe, S.grandis+ bunchgrass steppe, S.krylavii steppe, Ar.frigida steppe and eight non-grassland types: active cropland, harvested cropland, urban area, wetland, desertified land, saline and alkaline land, cloud, water body + cloud shadow. To eliminate the classification error existing among different sub-types of the same gross type, the 17 sub-class land cover types were grouped into five gross types: meadow grassland, temperate grassland, desert grassland, cropland and non-grassland. The overall classification accuracy of the five land cover types was 81.0% for 1987, 81.7% for 1991, 80.1% for 1997 and 78.2% for 2000.展开更多
Under the increasing pressure of water shortage and steppe degradation,information on the hydrological cycle in steppe region in Inner Mongolia,China is urgently needed.An intensive investigation of the temporal varia...Under the increasing pressure of water shortage and steppe degradation,information on the hydrological cycle in steppe region in Inner Mongolia,China is urgently needed.An intensive investigation of the temporal variations ofδD andδ1 8O in precipitation was conducted in 2007-2008 in the Xilin River Basin,Inner Mongolia in the northern China.TheδD andδ1 8O values for 54 precipitation samples range from+1.1‰to-34.7‰and-3.0‰to -269‰,respectively.This wide range indicates that stable isotopes in precipitation are primarily controlled by different condensation mechanisms as a function of air temperature and varying sources of vapor.The relationship between δD andδ1 8 O defined a well constrained line given by δD =7.89 δ18O+9.5,which is nearly identical to the Meteoric Water Line in the northern China.The temperature effect is clearly displayed in this area.The results of backward tra- jectory of each precipitation day show that the vapor of the precipitation in cold season(October to March)mainly originates from the west while the moisture source is more complicated in warm season(April to September).A light precipitation amount effect existes at the precipitation event scale in this area.The vapor source of precipitation with higher d-excesses are mainly from the west wind or neighboring inland area and precipitation with lower d-excesses from a monsoon source from the southeastern China.展开更多
基金Knowledge Innovation Project of CAS No.KZCX02-308+1 种基金 The NASA Land Use and Land Cover Change Program No.NAG5-11160
文摘This study conducted computer-aided image analysis of land use and land cover in Xilin River Basin, Inner Mongolia, using 4 sets of Landsat TM/ETM+ images acquired on July 31, 1987, August 11, 1991, September 27, 1997 and May 23, 2000, respectively. Primarily, 17 sub-class land cover types were recognized, including nine grassland types at community level: F.sibiricum steppe, S.baicalensis steppe, A.chinensis+ forbs steppe, A.chinensis+ bunchgrass steppe, A.chinensis+ Ar.frigida steppe, S.grandis+ A.chinensis steppe, S.grandis+ bunchgrass steppe, S.krylavii steppe, Ar.frigida steppe and eight non-grassland types: active cropland, harvested cropland, urban area, wetland, desertified land, saline and alkaline land, cloud, water body + cloud shadow. To eliminate the classification error existing among different sub-types of the same gross type, the 17 sub-class land cover types were grouped into five gross types: meadow grassland, temperate grassland, desert grassland, cropland and non-grassland. The overall classification accuracy of the five land cover types was 81.0% for 1987, 81.7% for 1991, 80.1% for 1997 and 78.2% for 2000.
基金Under the auspices of Nation Basic Research Program of China(No.2007CB411502)German Science Foundation(Research Unit 536)Independent Research Project from State Key Laboratory of Cryospheric Science(No.SKLCS-ZZ-2010-02)
文摘Under the increasing pressure of water shortage and steppe degradation,information on the hydrological cycle in steppe region in Inner Mongolia,China is urgently needed.An intensive investigation of the temporal variations ofδD andδ1 8O in precipitation was conducted in 2007-2008 in the Xilin River Basin,Inner Mongolia in the northern China.TheδD andδ1 8O values for 54 precipitation samples range from+1.1‰to-34.7‰and-3.0‰to -269‰,respectively.This wide range indicates that stable isotopes in precipitation are primarily controlled by different condensation mechanisms as a function of air temperature and varying sources of vapor.The relationship between δD andδ1 8 O defined a well constrained line given by δD =7.89 δ18O+9.5,which is nearly identical to the Meteoric Water Line in the northern China.The temperature effect is clearly displayed in this area.The results of backward tra- jectory of each precipitation day show that the vapor of the precipitation in cold season(October to March)mainly originates from the west while the moisture source is more complicated in warm season(April to September).A light precipitation amount effect existes at the precipitation event scale in this area.The vapor source of precipitation with higher d-excesses are mainly from the west wind or neighboring inland area and precipitation with lower d-excesses from a monsoon source from the southeastern China.
