青藏高原湖泊变化遥感监测及水量平衡定量估算研究进展

A review on the research of remote sensing monitoring of lake changes and quantitative estimation of lake water balance in Qinghai-Tibet Plateau

青藏高原湖泊是气候变化的重要指示器,20世纪90年代中期以来,在暖湿化环境下降水增多和冰川冻土加速融化导致的湖泊扩张是青藏高原最为突出的环境变化特征。值得注意的是,湖泊水位变化的空间分布特征和西风带及印度季风带影响区的降水量变化具有高度的空间一致性。严酷的自然环境导致对青藏高原内陆湖泊的实地观测变得难以企及,而遥感技术的发展正好可以克服以上局限,该技术已经成为青藏高原湖泊变化监测的主要研究手段。本文围绕遥感监测技术与方法,综述了青藏高原湖泊面积、水量、冰物候、水体参数以及水量平衡定量估算等方面的研究进展。部分研究以流域为尺度应用多源遥感与水文模型进行水量平衡定量评估,结果表明青藏高原内陆地区的湖泊水量增加的主要贡献因素是降水增多,而冰川融化、冻土消融及其他因素的贡献程度却相对较小。当前,学术界一般认为:大尺度的降水年代际变化是青藏高原湖泊近期变化的主要原因,而冰川冻土加速消融又进一步加速湖泊扩张或抑制了部分湖泊收缩。过去,关于青藏高原湖泊变化的气候响应机制研究大多停留在对降水、蒸发、温度、风速、冰冻圈融化等气候因素的定性描述上;现在,在湖泊水量平衡方面,越来越多的研究开始在定量化方面取得进展;将来,随着更多遥感数据的开放共享,以及更多水文与气象站点的投入使用,将为青藏高原湖泊的水量平衡定量研究提供更好的数据条件。

Lakes over the Qinghai-Tibet Plateau are considered as the important indicators of regional climate variability.Since the mid-1990s,the expansion caused by the increasing precipitation due to the warming and humidifying environment and the accelerated melting of glacier and frozen soil has been the most prominent environmental change feature of Qinghai-Tibet Plateau.It is worth mentioning that the spatial distribution characteristics of lake water level changes are highly consistent with the precipitation changes in the affected areas of Westerlies and Indian monsoon zone.The harsh natural environment makes it difficult to achieve the field observations of inland lakes on the Qinghai-Tibet Plateau.Currently,the development of remote sensing technologies can overcome the above-mentioned limitations,which has become the main research means of lake change monitoring on the Qinghai-Tibet Plateau.Based on the remote sensing monitoring technologies and methods,this paper summarized the research progress on the aspects of lake extent extraction,water volume change,water environment and ice phenology.Some studies have applied multi-source remote sensing and hydrological models to quantitatively evaluate water balance in the basin scale.The results have shown that the main contribution factor of lake water increase in inland areas of Qinghai-Tibet Plateau was the increase of precipitation,while the contribution of glacier melting,frozen soil melting and other factors was relatively small.Currently,academic circles generally believe that the annual variation of precipitation is the main reason for the recent changes of lakes in Qinghai-Tibet Plateau,and the accelerated melting of glacier and frozen soil further accelerates the expansion of lakes or inhibits the contraction of some lakes.The previous research on the climate response mechanism of lake changes in the Qinghai-Tibet Plateau was mostly limited to the qualitative description of climate factors,such as precipitation,evaporation,temperature,wind speed and glacier melting,etc.Now,in the aspect of lake water balance,more and more researches are making progress in quantification.In the future,with the open sharing of more remote sensing data as well as the building of more hydrological and meteorological stations,better data conditions will be provided for the quantitative research on water balance of lakes on the Qinghai-Tibet Plateau.