1972年以来羊卓雍错流域湖泊水域面积变化特征

Characteristics of variation of lake water area in Yamzho-Yumco Basin since 1972

摘要

【目的】青藏高原分布着众多内陆湖泊，湖泊水域面积变化能够指示区域气候变化和湖泊演化趋势。为了分析羊卓雍错流域内湖泊水域面积的变化趋势与特征，【方法】选取1972—2023年期间的Landsat卫星影像，采用归一化水体指数方法提取羊卓雍错、巴纠错、空母错、沉错、多错、普莫雍错的水域面积信息，重建近50 a各湖泊面积的日变化和年变化序列。借助GPS实地观测数据，评估了湖泊水域边界识别中的总体误差。基于流域附近的气象台站数据和线性趋势分析，探讨湖泊水域面积变化的驱动因素。【结果】结果显示：1972—2023年期间羊卓雍错、空母错、沉错、巴纠错的水域面积呈萎缩趋势，普莫雍错和多错的水域面积呈扩张趋势，普莫雍错的西部边界扩张较为显著。与1972年年均水域面积相比，2023年羊卓雍错、空母错、巴纠错、沉错的年均水域面积分别缩减了82.72 km²、2.2 km²、2.0 km²、0.9 km²;普莫雍错、多错的年均水域面积分别扩张了8.3 km²、0.4 km²。【结论】结果表明：根据台站气象要素的线性分析，1972—2023年期间年均气温、年降水量均呈增加趋势，但是年降水量增加不明显；相对湿度和年蒸发量呈减少趋势，但相对湿度减少不明显。总体上，羊卓雍错流域的区域气候正在处于“暖湿化”状态，而湖泊水域表面蒸发和冰雪融水对湖泊水域面积变化的作用机理不可忽视。

Abstract

[Objective] The mass inland lakes were distributed on the Xizang Plateau, and both the regional climate change and lake evolution trends could be indicated by changes of lake water area. The trend and characteristics of lake water area change in the Yamzho-Yumco basin was analyzed in the period of 1972—2023. [Methods] These Landsat satellite images were used to extract on the water area of Yamzho-Yumco, Bajiu Co, Kongmu Co, Chen Co, Duo Co, and Puma Yumco, based on the normalized difference water index method. The variation series of daily and annual lake water area were reconstructed in the past 50 years. The GPS measured data were applied to evaluate on the overall error of lake water boundaries. These driving factors of lake water area change were discussed on the data of meteorological stations near the basin, based on linear trend analysis. [Results] In the period of 1972—2023, the lake water area of Yamzho-Yumco, Kongmu Co, Chen Co and Bajiu Co were shrinking. In the meantime, the lake water area of Puma Yumco and Duo Co were expanding. The expansion on the western boundary of Puma Yumco was more obvious. Compared with the average annual water area in 1972, the average annual water areas of Yamzho-Yumco, Kongmu Co, Bajiu Co and Chen Co had shrunk by 82.72 km², 2.2 km², 2.0 km², 0.9 km² in 2023, respectively. The average annual water areas of Puma Yumco and Duo Co had expanded by 8.3 km² and 0.4 km², respectively. [Conclusion] According to the linear analysis, the meteorological element data of the station showed that the average annual temperature and annual precipitation had an increasing tend from 1972 to 2023, but the annual precipitation did not increase significantly. At the same time, the relative humidity and annual evaporation had a decreasing tend, but the relative humidity did not decrease significantly. Overall, the regional climate in Yamzho-Yumco basin was in the warm and humid state, and the mechanism of lake water surface evaporation and glacial-snow meltwater could not be ignored in the process of lake water area change.

关键词

卫星遥感 / 湖泊面积 / 空间分析 / 不确定性 / 时变序列 / 时空分布 / 降水 / 气候变化 / 影响因素

Key words

satellite remote sensing / lake water area / spatial analysis / uncertainty / time-varying series / spatial-temporal distribution / precipitation / climate change / influencing factors

基金资助

国家自然科学基金重点项目(42130516)

国家自然科学基金青年项目(41601067)