ESTARFM模型在西藏色林错湖面积时空变化中的应用分析(1976-2014年)

湖泊（特别是内陆湖）作为全球气候变化的敏感区域,是气候变化与环境变异的指示器,其面积变化在一定程度上可反映区域的气候变化。因此,精确监测湖泊面积的时空变化,对分析区域生态环境变化具有重要的意义。本文基于ESTARFM时空数据融合模型,利用MODIS数据模拟了2000年后无法得到的Landsat数据;利用NDWI和MNDWI 2种水体指数并辅以DEM数据分析了1976-2014年西藏色林错湖湖面面积的时空变化;综合湖区周围6个气象站点的气象数据(1970-2014年),探究了湖面面积变化的原因及其对气候变化的响应。结果表明：(1)利用ESTARFM时空融合模型得到的Landsat-Like数据与真实的Landsat数据在水体信息提取方面具有较高的相关性,R²可达0.93,时空数据融合的结果可用于湖泊水体的信息提取;(2)近40年来（1976-2014年）,色林错湖处于持续扩张状态,面积呈较显著的增长趋势,增加了近711.652 km²,增幅为42.36%,年平均增长速率约为18.728 km²a^-1,增长最快时可达55.954 km²a^-1;湖面面积变化先后经历了平稳变化-迅速变化-平稳变化3个阶段;北部湖区在40年间变化最为明显,向北扩展了约22.812 km;2003-2005年,南部湖区已与雅根错湖连为一体,随后二者共同扩张;(3)气温的持续升高造成的冰雪融水补给增加可能是导致湖泊面积扩张的主要因素,风速的降低为次要因素,湖面的面积变化与降水量、日照时数的变化相关性不明显。

Temporal and Spatial Variation Analysis of the Area of Siling Co Lake in Tibet Based on ESTARFM (1976-2014)

Lakes, especially the inland lakes, are sensitive to global climate change, which are the indicator of environmental variation. The area of lakes can reflect local climate change information. Thus, the rapid and accurate monitor of the dynamic change of the lake area is of great significance to analyze regional ecological environment. Based on MODIS data, this study used ESTARFM to simulate the Landsat data which are unavailable after 2000, and utilized two types of water index assisted by DEM data to analyze the dynamic area change of Siling Co Lake in Tibet from 1976 to 2014. Then, we analyzed the reasons of lake area change and its respond to climate change using the meteorological data acquired by six adjacent meteorological stations from 1976 to 2014. Conclusions can be made according to the results as the following statements. (1) The Landsat-like data acquired by ESTARFM was consistent to the real Landsat data in water information extraction, whose determination coefficient can reach a value of greater than 0.93. So, the fused data can be applied to extract the information of lakes. (2) Siling Co kept expanding from 1976 to 2014, the area of which increased approximately 711.652 km², which is 42.36% larger. The average annual growth was about 18.728 km², and the largest annual increase was up to 55.954 km². The whole process of lake area change can be divided into three stages: the smooth change, the rapid change, and the smooth change again. The northern region changed most obviously, extending northward for about 22.812 km². From 2003 to 2005, the southern region was integrated with Ya Gencuo Lake, and then they expanded together. (3) The snow-ice melting water supply caused by global warming might be the main reason for lake spread, and the decrease of wind speed was the secondary factor. However, the amount of precipitation and sunshine duration were poorly related to the lake area change.