A study on the analysis of climate change and hydrologic cycle in the Central and East Asia

本研究旨在探讨中亚和东亚地区土地覆被变化状况、微地形分布、气象数据、水文数据与气候变化和水文动力学之间的详细关系。在大范围土地覆盖状况分析方面，首次建立了基于ADEOSII/GLI和Terra/MODIS的新的卫星数据集，开发了数据处理算法。其次，通过对现有卫星数据集与新数据集的比较分析，确定了过去约40年的土地覆盖变化区域。在此基础上，分析了流域内封湖面积、植被面积和冰雪覆盖面积的显著变化，并对准噶尔盆地和西部戈壁荒漠的湖泊水域面积、灌溉农田面积和冰雪覆盖面积的变化进行了分析。研究了一种基于长周期波动的封闭湖泊周边微地形分布检测算法及其应用。结果表明，在较长的时间内，干旱趋势较为平缓，1990年后期的干旱趋势较为迅速，变化较为复杂。从气候变化的大陆尺度分析结果可以看出，中亚地区的气候变暖趋势显著，其迹象在20世纪上半叶就已出现。80年代后中纬度地区的水文循环研究也认识到降水减少和蒸散增加导致径流量减少的现象。

This study aimed to investigate the detailed relationship among land cover change situation, distribution of microtopography, meteorological data, hydrological data, and climate change and hydrological dynamics in the Central and East Asia. As for the analysis of the wide range land cover condition, new satellite data sets based on ADEOSII/GLI and Terra/MODIS were firstly created through the development of an algorism for the data processing. Next, land cover change areas for the past about 40 years were detected by the comparative analysis of the existing satellite data sets with new ones. Then, the investigation of the remarkable change in the closed lake, the vegetation area and snow ice cover area in the catchments area was carried out.The change in the lake water areas, irrigation agricultural lands and snow ice cover areas in Dzungar Basin and Gobi desert of west China was investigated by analyzing data sets. The development of an algorithm and its application to detect the distribution of microtopography around closed lake based on the fluctuation for long period were carried out. The result showed the gentle drying tendency for long period, rapid drying in the late 1990 and the complicated change. It could be grasped that the phenomena was due to the climate change in wide range area and the artificial influence by water resources control.On the other hand, the analysis result of climate change in continental scale showed that the warming tendency in the Central Asia was remarkable, and its sign has appeared since the first half of twenty centuries. Furthermore, the decline of the runoff caused by the decrease in precipitation and the increase in the evapotranspiration was recognized by the investigation of the hydrological cycle after the 1980's in the middle latitude zone.