青藏高原不同气候子区典型湖泊多时间尺度变化的遥感对比研究

A Comparative Study on the Changes of Typical Lakes in Different Climate Zones of the Tibetan Plateau at Multi-timescales based on Remote Sensing Observations

青藏高原湖泊作为气候变化的重要指示器,监测高原湖泊水位变化对于准确评估该地区的气候及其对周围水文与环境的影响至关重要。而由于青藏高原地理环境复杂且恶劣,难以对湖泊进行长时间、连续的实地观测,但遥感技术的发展弥补了这个不足。利用多源测高卫星数据可以有效地监测湖泊水位长时序连续变化,促进对青藏高原湖泊气候变化响应特征的理解。基于Hydroweb多源测高水位同化数据,结合气温和降水地面观测资料,从年代际和年际变化、季节性变化以及极端干湿年份等不同时间尺度上对比青海湖和色林错的水位变化特征。并据此探讨了青藏高原湖泊变化的时空异质性,以及处于不同气候子区的湖泊变化响应特征。结果表明:青海湖和色林错水位变化差异较大,青海湖水位从1998年至2004年逐年下降,随着降雨量的增加,从2005年开始水位才开始上涨,直到2018年已经累计涨幅2.95 m;色林错水位从1998年开始,除了2015、2016两年水位有所下降外,一直处于增长状态,尤其前半段2000~2010年水位上涨更为迅速,年增率约0.8 m/a。最后,发现并讨论了青海湖和色林错的水位变化对于不同气候特征的响应规律,为下一步结合遥感观测和水文模型深入开展湖泊变化的驱动机制研究提供了基础。

Lakes in the Tibetan Plateau are important indicators of climate change.Monitoring the water level changes of the plateau lakes is essential for an accurate evaluation of regional climate change and its impact on the surrounding hydrologic environment.Because of the remoteness and poor accessibility of these alpine lakes,it is difficult to conduct long-term and continuous in-situ observation of lakes,yet the development of remote sensing technology has partly solve the difficulty.The use of multi-source altimetry satellite data can effectively monitor the continuous variation of lake water level and improve the understanding of climate change response characteristics of lakes in the Tibetan Plateau.Based on multi-source altimetry water level assimilation data accessed at Hydroweb,lake inundation area mapping results,combined with temperature and precipitation ground observation data,water level change characteristics of Qinghai Lake and Siling Co are analyzed from a comparative perspective on different time scales such as multi-decadal and interannual,seasonal,extreme dry and wet years.Based on this,the spatio-temporal difference of lake changes in the Tibetan Plateau and the response characteristics of lakes in different climate sub-regions are discussed.The results show that the water level difference between Qinghai Lake and Siling Co is quite obvious.The water level of Qinghai Lake had decreased year by year from 1998 to 2004.As rainfall increases,the water level began to rise from 2005,and the cumulative increase has been 2.95 m until 2018.The water level of Siling Co has been growing since 1998,except for 2015 and 2016.The water level rose more rapidly from 2000 to 2010,with an annual growth rate of about 0.8 m/a.Finally,we have found and discussed the response of the water level changes of Qinghai Lake and Siling Co to different climatic characteristics,and provided the basis for further research on the driving mechanism of lake change in combination with remote sensing observation and hydrological model.