2003-2011年青藏高原佩枯错相对水量变化及其对气候变化的响应

湖泊的退缩与扩张是全球气候变化的指示器.利用2003-2011年Landsat ETM数据和2003-2009年ICESat激光测高数据, 分别对青藏高原佩枯错湖泊的面积和高程变化进行了分析, 并进一步估算了湖泊2003-2009年相对水量变化.结果表明: 佩枯错面积年内变化明显, 湖泊面积冬季最小, 春季出现小峰值, 秋季达到最大; 面积年内波动明显(1.18%), 但在冬季、 春季和秋季相对稳定, 波动范围分别为0.26%、 0.1%和0.29%. 2003-2011年湖泊呈退缩趋势, 冬季、 春季和秋季面积年际变化率分别为-0.52 km²·a^-1、-0.35 km²·a^-1和-0.61 km²·a^-1; 2003-2009年间湖泊水位下降了1.17 m, 变化率为-0.05 m·a^-1; 2003-2010年, 冬季总水量减少了2.51×10⁸ m³, 春季总水量减少了1.74×10⁸m³, 秋季总水量减少了2.80×10⁸ m³, 平均相对水量变化率分别为-0.35×10⁸ m³·a^-1、-0.21×10⁸ m³·a^-1、-0.37×10⁸ m³·a^-1. 从空间上看, 湖泊退缩主要发生在东北角、 东南角和西南角.气候因素分析表明, 佩枯错湖泊退缩秋季主要是因为夏半年平均气温的升高, 冬季和春季则主要是因为冬半年降水量的减少.

Water Volume Change of the Paiku Co in the Southern Tibetan Plateau and Its Response to Climate Change in 2003-2011

Lake shrinkage and expansion is an indicator of global climate change. In this study, variation in lake area and water level of the Paiku Co in southern Tibetan Plateau was examined by Landsat ETM images from 2003 to 2011 and ICESat altimetry data from 2003 to 2009. The results are as follows: 1) the monthly variation of the lake area is apparent. However, seasonal fluctuation of it is small, based on which further calculating is feasibility; 2) the lake area had decreased obviously from 2003 to 2011, with the rate of 0.52 km²·a^-1 in winter, 0.35 km²·a^-1 in spring and 0.61 km²·a^-1 in autumn; 3) the lake level had decreased 1.17 m from 2003 to 2009 with the rate of 0.05 m·a^-1; 4) from 2003 to 2009, the water storage had decreased 0.35×10⁸ m³·a^-1in winter, 0.21×10⁸ m³·a^-1in spring and 0.37×10⁸ m·a^-1in autumn; 5) spatially, the most obviously retreating parts were the northeast corner, the southeast corner and the southwest corner. Meteorological analysis shows that the increase of air temperature in summer will be the dominant factor for the reduction of the lake in autumn, while the decrease of precipitation in winter will induce lake shrinking in winter and spring.