| Land cover is the important interface between terrestrial ecosystem and climate system. Actually, by utilizing the land resources, human society affects the biogeochemical feature of land cover, further, affects the structure and function of terrestrial ecosystem and so much as affects the climate system. In all, land cover is the key field of global change research.Based on the analysis of previous outcome and trend of land cover research, from the view of quantitative theory of remote sensing this thesis brings forward a research system of remote sensing on land cover. First, the biophysical features of land cover are rational contents of land cover. Second, the four key parameters of land cover (albedo, land surface temperature, vegetation index and net primary production) are retrieved from satellite data. Further, Land cover classification from the view of ecosystem is brought forward. This thesis not only analyzes the seasonal variation of land cover, but also analyzes land cover change during the past 20 years In addition, tracks and source areas of Asian dust, dust loading and balance study of soil organic matter are under study. Based on the above researches, this thesis makes correlative analysis of land cover change and dust trend in China. This thesis includes the following contents,1. Construction of quantitative system of land cover classificationBased on the analysis of China vegetation classification system, China land resource classification system, America national land cover data (NLCD) system,IGBP,USGS and Holdridge vegetation-climate classification system, thisthesis indicates that biophysical features of land cover are rational contents of land cover and quantitative parameters should be used to describe the land cover type. On the basis of retrieve of biophysical parameters (albedo, land surface temperature, vegetation index and net primary production) from remote sensing data, this thesis brings forward a classification system, in which every land cover type is corresponding to specific value of biophysical parameters.2. Study of variation of land surface temperature in ChinaBy using a suitable split window algorithm on large scale, the authors retrieved the yearly and monthly land surface temperature(LST) from the thermal bands of NOAA-AVHRR data set over China. The result indicates that the variation of LST has some specific features and is different from that of air temperature.As to LST, the hottest part is in Northwest drought region, the higher LST part is in Southeast region, and the low LST parts are in Tibet plateau and Northeast region. Moreover, there is no 0癈 isotherm of annual LST over China. Further, the 0癈 isotherm of LST in January lies higher in latitude than that of air temperature. And Eastern Tibet and Western Tibet have different seasonal features of LST.3. Building of database of land cover features in ChinaBased on the analysis and compare of current retrieval algorithms, this thesis utilizes a suitable algorithm on large scale to calculate albedo, land surface temperature, vegetation index and net primary production with a temporal resolution of month, and build the database of land cover features in China.4. Land cover classification from the view of ecosystemEcosystem as a whole is composed of biology and its environment (such as soil and atmosphere), and there exist transform and utilization of substance and energy in an ecosystem. However, remote sensing directly observes the radiation energy of upper layer of ecosystem, the radiation energy includes a lot of information about land surface and ecosystem, and these uncovered feature about ecosystem can be used to make land cover classification.Absorptivity( a ),land surface temperature(Ts), vegetation index(NDVI) and net primary production(NPP) can be retrieved from remote sensing(such as AVHRR data), a and Ts represent the energy feature of ecosystem, and NDVI and NPP represent the substance feature of ecosystem. These four bio-parameters have close relationship with speci...
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