21世纪以来泛北极湖泊水位变化时空特征及原因探讨

Spatial-temporal characteristics and causes of pan-Arctic lake water level changes since the 21st century

在全球气候变暖和极端气候事件增加的背景下,流域水文循环过程受到的影响越来越强烈,导致湖泊水位变化表现出复杂的时空特征。而泛北极地区是地球上湖泊数量与面积分布最为集中的区域之一,该地区湖泊对气候变化响应非常敏感。因此,了解这些湖泊近期水文变化特征十分必要。本研究共搜集了36个泛北极大型湖泊(>500 km^(2))基于遥感或站点观测的近20年水位数据,分析其时空变化特征。本文使用线性回归模型来估算湖泊水位的变化趋势,进而利用皮尔逊相关分析了其主要水文影响变量和大气环流机制,并运用Mann-Kendall突变检验法探讨了水位突变的原因。结果表明,泛北极湖泊的水位整体上呈现不同程度上升(平均速率为0.013 m/a),有23个(64%)湖泊的水位呈上升趋势;研究湖泊中有10个通过90%统计显著性检验。其中,水位上升速率最大的湖泊是位于哈萨克斯坦的腾吉兹湖,上升速率为0.078 m/a。泛北极湖泊水位的波动主要与径流有关,有19个(53%)湖泊的水位波动与径流的增加更为相关;相比而言,位于亚洲的极地湖泊水位的上升与流域蒸发的降低显著相关,尤其是库苏古尔湖。从区域大气环流影响来看,泛北极湖泊水位变化主要与厄尔尼诺-南方涛动有关,其次是北极涛动和北大西洋涛动。本研究有助于加深对泛北极湖泊近20年水位变化规律及气候影响特征的科学理解。

In the context of climate warming and intensified extreme climate events,the hydrological cycle and processes are increasingly affected,leading to certain spatial and temporal changes in hydrological elements.The pan-Arctic region is one of the most concentrated areas of lake distribution in both count and area on the Earth,and the lakes in this region are very sensitive to climate change.It is essential to understand the characteristics of recent hydrological changes of these lakes.In this study,the water level data for a total of 36 pan-Arctic large lakes(>500 km^(2))were collected over the past 20 years based on remote sensing or station observations,and their spatio-temporal variation characteristics were analyzed.We used a linear regression model to estimate the changing trend of lake water level,then used the Pearson correlation to analyze its main hydrological variables and atmospheric circulation factors.The Mann-Kendall mutation test was applied to explore the possible reasons for the abrupt changes in lake water level.The results indicated that the water levels of the pan-Arctic lakes showed different degrees of increase overall(mean rate at 0.013 m/a),with 23 lakes(64%)showing an increase in water levels.Only 10 lakes were featured by the linear trends at the 90%statistical significance.Lake Tengiz in Kazakhstan ranked the fastest among these rising lakes,with a change rate of 0.078 m/a.The changes in water level of these pan-Arctic lakes were mainly related to runoff variations,with 19 lakes(53%)showing correlations with increases in runoff.In comparison,increased water levels of the lakes located in Asia were significantly correlated with decreased evaporation,especially Lake Khovsgol.The pan-Arctic lake level changes were mainly associated with El Nino Southern Oscillation,followed by Arctic Oscillation and North Atlantic Oscillation.This study is expected to deepen our scientific understanding on the water level variation patterns and climate impact on the pan-Arctic lakes over the last 20 years.