西藏羊卓雍错近期湖水水位变化及其原因分析

分析了羊卓雍错湖水19742010年间的水位变化,特别是过去几年湖水水位的大幅度下降,并根据流域内浪卡子县气象数据分析了控制湖水水位变化的主要原因。计算了流域内降水累积距平及蒸发量累积距平,并与湖泊水位的年际变化进行了对比分析。研究结果表明,2005年以前羊卓雍湖湖水的水位年际变化与流域降水累积距平变化一致,而与蒸发量累积距平变化相反,降水与蒸发量变化可以解释93%的湖水水位变化。20052010年湖水水位变化偏离了降水量的变化趋势。分析表明,气候的变化远不能解释羊卓雍湖水位的快速下降,可能人为活动的影响,是导致羊卓雍湖水位下降的主要原因。

Recent Water Level Change of Yamzhog Yumco Lake, Tibet

We studied the water level changes of the Yamzhog Yumco Lake from 1974 to 2010 and discussed the factors thatcaused the lake water level changes by comparing the meteorological data from the Langkazi meteorological station with theobserved lake water level changes. We calculated the accumulated anomaly of annual precipitation and annual potential evaporationfrom the meteorological station and compared it with the water level changes of Yamzhog Yumco Lake. The results show that theaccumulated anomaly of annual precipitation had consistency with the inter-annual water level change of the Yamzhog Yumco Lakebefore 2005, indicating a precipitation dominated lake water level change. The combination effect of precipitation and evaporationchanges can account for 93% of the lake level change. From 2005 to 2010, however, the observed lake level deviated from theprecipitation change trend. The study shows that the climate change can not interpret why the water level quickly decrease in thepast years. Probably, the human activity is one of the main factors leading to the water level decrease in the Yamzhog YumcoLake.