Analysis of lake level changes in Nam Co in central Tibet utilizing synergistic satellite altimetry and optical imagery
Analysis of lake level changes in Nam Co in central Tibet utilizing synergistic satellite altimetry and optical imagery
复制标题
卫星测高与光学影像协同分析西藏中部纳木错湖水位变化
DOI：
10.1016/j.jag.2011.10.001
复制
发表时间：
2012-07-01
影响因子：
7.5
通讯作者：
Hochschild, Volker
中科院分区：
文献类型：
--
作者：
Kropacek, Jan;Braun, Andreas;Hochschild, Volker
青藏高原封闭流域湖泊的波动是气候变化引起的流域水量平衡变化的宝贵记录。由于这些流域地处偏远，难以进入，因此多传感器遥感是一种宝贵的方法，可以在适当的空间覆盖范围内，以高时间分辨率收集必要的水收支组成部分。以西藏纳木错湖为例，通过卫星测高资料的对比分析，研究了该湖水位高程的变化（RA-2/ENVISAT，GFO雷达高度计和GLAS/ICESat激光高度计（2000-2009年）以及对可追溯至1976年（Landsat）和1965年（Corona）的光学卫星数据时间序列的评价以验证水文水收支模拟结果。所有三个高度计的组合显示，2000-2009年期间，湖平面平均上升0.31 m/年，相当于总体积变化6.2 km（3）。这与从分布式水文模型中获得的0.35米/年的模拟平均湖平面上升非常一致（Krause等人，2010年）。卫星图像上测量到的湖岸移动证实了测高数据所揭示的趋势，也表明了自1965年以来的上升趋势。虽然GFO提供了密集的时间序列数据，但更准确的ENVISAT/RA-2数据不幸地在西藏地区存在较大的数据缺口。ICESat有限时间活动的测量结果验证了雷达测高的结果，它们提供了不同于雷达高度计的冬季和春季湖冰上方的有效高度。结果表明，所提出的方法是一个有价值的贡献，了解气候变化对西藏湖泊水文的影响。(C)2011 Elsevier B. V.保留所有权利。
The fluctuations of closed basin lakes on the Tibetan Plateau are a valuable record of climate change induced water balance alterations within the catchments. Since these basins are remote and hard to access, multisensoral remote sensing is a valuable method to gather the necessary water budget components with appropriate spatial coverage and with high temporal resolutions. Thus the lake level elevation changes of the central Tibetan lake Nam Co were examined in example by a comparison of satellite altimetry (RA-2/ENVISAT, GFO radar altimeters and GLAS/ICESat laser altimeter for the period 2000-2009) and the evaluation of a time series of optical satellite data dating back to 1976 (Landsat) and 1965 (Corona) in order to validate hydrological water budget modelling results. The combination of all three altimeters revealed a rising trend of lake level on average by 0.31 m/year in the period 2000-2009 which corresponds to a total volume change of 6.2 km(3). This is in a good agreement with simulated average lake level rise of 0.35 m/year obtained from distributed hydrological modelling (Krause et al., 2010). The movements of lakeshore measured on the satellite imagery confirm the trend revealed by the altimetry data and they also indicate the rising trend since 1965. While GFO provides a dense time series of data the more accurate ENVISAT/RA-2 data unfortunately feature large data gaps over Tibet. The measurements from time limited campaigns of ICESat validate the results of radar altimetry and they provide unlike radar altimeters a valid height over lake ice during winter and spring period. The results show that the presented approach is a valuable contribution to understand the impact of changing climate on the hydrology of Tibetan lakes. (C) 2011 Elsevier B.V. All rights reserved.