基于星载雷达测高资料的中国西北地区冰川物质平衡时空变化特征研究

The mountain glacier mass balance is not only one of the important parts in the glaciological research, but also is an important part of monitoring climate change. The change of the glacier mass balance is directly related to the river-basin water mass balance and the regional water resources sustainable utilization. At present, the objective is to quantify the proportion of the precipitation increased and the glacial mass change contribution to the inland lake water storage of northwest China, while the coupling system of climate change-glacier-lake under natural climatic conditions is still in the blank state. The project is on the basis of comprehensive observation of glacier meteorology, glacier mass balance, snow and ice features in the mountain glacier regions of the arid and semi arid area of Northwest China. The multi-source and temporal spaceborne radar altimeter data are employed for estimating the river-basin glacier mass balance and the temporal and spatial change during the period of 1990-2015, , and further to reveal on the ratio of the glacier mass change contribution into lakes water storage proportion under climate warming. Integrated with the meteorological observation station, the lake water level and the glacier mass balance, the lake level-storage volume models are derived from the multi-spectral remote sensing data and the multi-source spaceborne altimeter data, which reveal on how the river-basin glacier mass balance influence on the inland lake level and storage fluctuations. It is significant that the clarification on the relationship of the lake water storage change and the glacier mass balance, under the impact of the natural climatic change, which lay the foundation to further clarify the rational development and utilization of the glacial water resources in Northwest China.

山地冰川物质平衡是冰川学研究重要内容之一，也是气候变化监测指标，其变化直接关系到流域尺度水量平衡和水资源可持续利用问题。目前，中国西北气候变化-冰川物质平衡-湖泊系统在自然气候条件下的流域冰川物质质量变化对湖泊水量贡献研究还处于空白状态。本项目以中国西北半干旱、干旱地区山地冰川为例，在对冰川气象、冰川物质平衡、冰雪特征等综合观测的基础上，借助1990-2015年间多源多时相星载雷达测高数据进行流域尺度冰川物质亏损量和物质平衡时空变化特征研究，旨在探索气候变暖情况下流域冰川物质质量和降水变化对下游湖泊水量贡献。综合流域台站气象要素、湖泊水位和冰川物质平衡观测，通过多源多光谱遥感数据和雷达测高资料建立冰川补给湖泊水位-水量关系模型，揭示流域冰川物质平衡对湖泊水位-水量波动规律及影响，对明确气候变化、冰川物质平衡对湖泊水量平衡具有重要意义，为进一步阐明中国西北地区冰川水资源合理开发与奠定基础。

在气候变化-冰川物质平衡-湖泊系统中，流域冰川物质质量变化对湖泊水量贡献研究处于空白。本项目以中国地区西北典型山地冰川和湖泊为例，在对冰川气象、物质平衡等观测基础上，借助星载ICEsat测高数据分析流域尺度冰川物质亏损量和物质平衡时空特征，分析流域冰川物质亏损和降水变化对湖泊水量贡献。受年降水量和夏季降水量增加，哈拉湖水位呈增加，但流域冰川亏损不明显；与2000年相比，湖泊面积增加了21.4±4.8km2，湖泊水位增加了1.68±0.26m，相应的湖泊水容量增加了16.1±0.3亿m3。冰川亏损量、降水量增加对哈拉湖水量的贡献率分别为39.65%，22.82%。利用1990-2015年Landsat TM/ETM/OLI影像和水体归一化指数提取博斯腾湖、青海湖、哈拉湖、湖泊水域面积；根据湖泊面积与水位、水量与水位的相关关系，构建湖泊面积-水位-水量时变序列。2015年博斯腾湖水域面积比1990年减少了32.20±3.5km2，年均水位下降了0.81±0.19m，湖泊水量减少了9.49±0.22亿m3。与1988年年均水位相比，2018年青海湖年均水位上升了1.93±0.22m，湖泊年均面积扩张了197.75±6.3km2，湖泊水量增加了8.93±0.12km3。通过湖泊水量变化、冰川亏损对湖泊水量的贡献分析，揭示在自然气候变化和人类活动下流域冰川水量平衡和可持续发展问题。