Calculation and analysis of water balance in Lake Hulun, Inner Mongolia

根据呼伦湖的实际水文过程,计算1963-1980年月水量平衡,在此基础上,分析库容与径流、径流+降雨、径流+降雨-蒸发的相关性.利用累积和分析水位、径流、降雨、蒸发年均值的突变情况,进而重点论述了2000年后水位持续降低的原因.同时,探讨各水平衡项的年内分布规律及相互关系.结果表明,2000年后水位的急剧降低是气候变化(暖干化)造成的.河川径流对水位的影响程度最大,其次为湖面降雨.每年4、5月,冰封期积累的降雪融化渗入地下补给湖泊,其他时间则由湖泊补给地下水.;The correlation between the storage capacity and runoff, runoff + precipitation, runoff + precipitation-evaporation was analysed at the basis of monthly water balance calculation in the period of 1963 and 1980 according to the real hydrological processes of the research site. At the same time, the intermediate-term changes in the mean value of water level, runoff, precipitation and evaporation were detected with the cumulative sum technique in order to find the reason of water level dropping after 2000. Meanwhile, the distribution and mutual relations of water balance terms in a year was analyzed. Results show that:climate change exhibited a warmer and dryer trend in recent years that might be the major cause for water resources deficit after 2000. The crucial influence on water level comes from runoff, followed by precipitation on the water surface. In April and May of each year, accumulated melt water infiltrate the soil and then recharge the lake, while in the other time the groundwater recharged by the lake.