针对北方寒旱区呼伦湖水位下降、水面萎缩的现象,根据气候特征,利用月水量平衡模型探究湖泊水文过程并揭示其变化规律.在此基础上,利用不同气候条件下各水平衡项对于湖泊水位的影响程度确定水位升降的直接原因.基于1963-1980年间水位的实测数据,根据水量平衡原理及其他辅助计算判断出湖泊与周边区域存在着地下水的交换,且具有一定的规律性,即历年11月至次年3月期间的累积降雪融化渗入土壤中形成浅层径流补给湖泊,而7、8月份湖泊补给周边草原.基于以上规律,根据周边坡面汇流、地下水与湖泊交换量的年内变化特征,利用水平衡方程式推算湖泊1981-2008年逐月水位变化,并与其他研究成果比较,吻合度较高.不同气候条件下,径流量对于湖泊水位的影响程度最为突出,是水位变化的主控因子.%In order to study the shrinkage of the Lake Hulun, monthly water balance model was used to analyze the characteristics and causes of water changes. Based on available continuous lake level monitoring data from 1963 to 1980, there are exchange between groundwater of surrounding areas and lake water according to the principle of water balance and other auxiliary calculations. The exchange has a certain regularity, which is the accumulated snow of the period from November to March when snows begin to melt and then infiltrate the soil with the increase of temperature. This part of water recharges the lake in the form of subsurface flow in spring, which causes the lake water level increases slightly. The lake will recharge the surrounding prairie through strong evaporation after July. On the basis of above observations, the unknown items, i. e. the exchange and overland flow, were taken into balance equation as a constant to simulate water level. There is high goodness of fit between simulated values and related research results. Finally, the influence of precipitation, runoff and evaporation under different climate scenarios on lake water level were used to determine the cause of the drastic decrease of the lake level. The results show that decline of the lake water level after 2000 is mainly due to the sharp drop of river runoff.
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