Remote Sensing Monitoring Of Snow Depth Change In North Part Of Xinjiang

Aiming for retrieving snow cover and snow depth, based upon the observed snow data and corresponding MODIS satellite data, utilizing GIS retrieval methods, systematic remote sensing theory and numerical simulation method, the paper developed the retrieval model of snow cover and depth of MODIS data, discussed the feedback and influence between snow depth and climate change.The paper selected the observed maximum snow depth data of 20 primary weather stations in north part of Xinjiang from 1971 to 2006, set up the time series of maximum snow depth; analyzed the data from Tianshan Snow-Cover and Avalanche Research Station and the concerned weather stations in Yili valley. Aiming for the snow depth and snow density in typical area, we did field observation in the winter of 2009 and 2010, took 127 samples and offered the first-hand data for model construction and verification. We collected MODIS data in clear days. Aiming for the difficulty in automatically identification of snow depth retrieval, combining statistical methods with spectrum features bank of various objects, considering the influence of substrate condition (including snow cover, albedo and density) and season on snow depth, the paper realized snow automatic classification and identification of cloud, snow, land surface and water.The study adopted the routine of interdisciplinarity from field experiment, data collection to model simulation and regional integration. Through the analysis on regional climate change and facts of snow observation, based on mapping of mountainous snow, the paper dealed with the data with the methods of integration of multi-data, grid calculation and snow cover calculation under the support of GIS spatial analysis technique, produced the snow product of observed area and natural catchments, and set up the snow depth retrieval model of EOS/MODIS snow remote sensing monitoring and GIS application.It indicated that the inter-annual change of seasonal snow in north part of Xinjiang was stable, with the indistinctive regional difference. Under the background of regional climate warming, the tendency of seasonal snow of the study area was consistent with that of Tibetan Plateau and icecap of polar area. Through three statistical tests of mean subtraction, least square, and auto-regressive moving-average, it was found that the seasonal snow in north part of Xinjiang increased under the regional warming background. The long-term change of seasonal snow was associated with the long-term fluctuation of winter temperature, and precipitation. The inter-annual change of seasonal snow change was weakly negative correlated with mean winter temperature and significantly positive correlated with winter precipitation.Through the analysis of MODIS satellite data and retrieval model, we understood the discipline of snow accumulation and distribution in north part of Xinjiang, offered critical ways to the qualitative, quantitative and dynamic analysis on snow in Xinjiang, expanded the service field of Xinjiang meteorological section, and provided the visual and timely service product for the decision-making on agriculture and animal husbandry production and the prevention and reduction of snow disaster.