Research On Remote Sensing Based LAI Inversion Using PROSAIL Medel In Inner Mongolian Grasslands

The Poyang Lake Basin is the very important department of the Yangtze River Basin. The ecological environment status significantly, it plays a pivotal role in maintaining ecosystem stability and ecological security of the lower Yangtze Region. As one of an important service of ecosystems in the basin, water regulation has become a hot point of Ecology. Long-term utilization of ecosystem in Poyang Basin has made serious shortage of water loss and soil erosion, water pollution and other natural disasters. Scientific evaluation of water regulation can provide a theoretical basis and decision-making reference for the ecological effects assessment of the program of Mountain-River-Lake and ecological compensation; it is also helpful on guidance of the scientific management of water resources and making policy.The article selected the district of Poyang Lake Basin located in Jiangxi province, first we collected and calculated the parameters and index of water regulation module, then the water regulation of Poyang Lake Basin was evaluated, change of amount of water regulation was analyzed during 1990 and 2013, the effects of land use changes and climate variability on the water regulation of the Poyang Lake Basin were last explored by using scenario analysis approach. The main conclusions were as follows:(1)The water regulation of the Poyang Lake Basin showed a trend of increasing and then decreasing from 1990 to 2013. The average amount of water regulation varied between 500 and 800mm. The trend of annual water regulation change was consistent with annual precipitation change and was different with the average potential evaporation change and real evaporation change, which showed the same trend of decreasing and then increasing from 1990 to 2013.(2)The spatial distribution of annual water regulation of the Poyang Lake Basin was similar. The plains of farmland ecosystem primarily had the lowest value of annual water regulation, which varied between 200 and 400mm. The northeast of basin had the highest value of annual water regulation, which varied between 800 and 1000mm. The amount of water regulation of the Poyang Lake Basin showed an increasing trend from 1990 to 2000, which increased from west to east, only the south of the Ganjiang River Basin were decreased. The annual water regulation showed a decreasing trend from 2000 to 2013, but the reduction of spatial pattern had difference.(3)The ecosystem type of the Poyang Lake Basin was given priority to forest ecosystem type, which accounted for more than 60%of the basin area. The ecosystem types of higher annual water regulation were wetland, forest and grassland, which varied between 500 and 1100mm. The ecosystem types of lower annual water regulation were cropland, settlement and desert, the average water regulation was less than 300mm.(4)The climate change and land cover change result in different spatiotemporal characteristic and pattern of water regulation. The dominant factor of increasing of annual water regulation was climate change from 1990 to 2000, at the same time, climate change and human activities caused by land cover changes (mainly the increase of forest area) were positive effect. The major factor of slightly increasing of annual water regulation was still climate change from 2000 to 2013, but the change of land cover caused by human activities (mainly urbanization) was negative effect.