2005年以来青海湖水位持续回升的原因分析

The reasons of rising water level in Lake Qinghai since 2005

地处干旱-半干旱过渡带的青海湖现代和历史时期生态环境变化一直受到关注,特别是2005年以来水位和湖面的逆转回升促使我们重新审视全球变暖情形下我国北方气候和环境的变化及其趋势。本文利用高分辨率的河水化学、(次)降水量和径流量等数据,探讨了2005年以来青海湖湖水的来源和水位持续回升的原因。结果表明,1959年以来青海湖水位的变化与降水量和径流量紧密相关;近些年的持续回升则主要取决于全球增暖情形下区域夏季降水强度和降水量的同时增加,地表径流和/或地下水补给起着一定作用,而冰川融水的贡献则十分有限。我们认为2005年以来青海湖水位持续回升是全球增暖情形下区域降雨模式的改变、降水量和径流量增加,以及流域植被生态改善的综合效应。

Much attention has been paid to the changes Qinghai in modern and past ecology and environment in Lake located at the transitional zone of arid and semi-arid, in particular after its rising water level and area since 2005, pushing us to re-evaluate climatic and environmental conditions and trend in the northern China under the scenario of global warming. In this paper, using high-resolution river water chemistry, in situ measured precipitation, individual rainfall and water discharge data, the sources of lake water and the reasons of rising water level in Lake Qinghai since 2005 were discussed. The results indicated that the variation in water level since 1959 in Lake Qinghai was related closely with the changes in both precipitation and runoff and that the rising water level in recent years in Lake Qinghai chiefly depended upon both increases in intensity of individual summer rainfall and annual precipitation under global warming. Meanwhile, discharge of river and/or groundwaters might also play a role in the rising water level since 2005, but the contribution of glacial melting water, if have, is very limited. We concluded that the rising water level in Lake Qinghai since 2005 is a comprehensive effect of changing rainfall pattern, increasing both precipitation and runoff, and improving grass vegetation within the catchment under the scenario of global warming.