珠穆朗玛峰绒布冰川消融与产汇流水文特征分析

Hydrological Characteristics of the Runoff Yield and Runoff Confluence in the Rongbuk Glacier Catchment in Mt. Qomolangma,Central Himalayas,China

分析珠穆朗玛峰峰绒布冰川强消融期6月的日径流资料可知,由于绒布冰川末端冰湖较为发育、冰川面积较大,冰川末端水文站显示白天流量小于晚上流量,冰川储水性较强.最大流量出现时间滞后於最高气温(消融最强)时间9～14h.随着消融强度增大,冰川排水系统发育越来越完善,滞后时间缩短.据2005年定日县气象站无降水日日平均气温资料和同期珠穆朗玛峰绒布河日均径流量,获得气温驱动下绒布河日均径流量表达式;利用1959年珠峰科考时一个水文年中无降水日绒布河日均流量资料和同期定日县气象站日均气温检验该表达式表明,该表达式在利用定日县气象站无降水日日均气温模拟绒布河径流量时表现较好.绒布河的径流可分割成两部分:冰川融水补给和降水补给.根据1959年降水驱动产生的流量,得出降水对河流补给贡献率为19.2%,冰川融水补给率为80.8%.

The daytime discharge was less than the night-time discharge in the Rongbuk Glacier catchment in June 2005,because of the large glacierized area and many glacier-lakes immediately beneath the glacier,which indicated that the glacier had pronounced water storage function. Between the maximum discharge and the maximum temperature there was a time-lag of 9~14 hours. As the glacier ablation went on,the glacier drainage system became perfect and the time-lag decreased. An exponential formula was developed between daily mean discharge in the gauging site and daily mean temperature in Tingri County for the clear weather days. The formula was validated by the daily mean temperature and daily mean discharge in 1959,when a scientific expedition was carried out. Calculated discharge and modeled discharge by the formula during the rainy days were compared and a discharge difference was found. It is believed that the difference was induced by precipitation,accounting for 19.2% of the total discharge. The discharge induced by glacier ablation accounted for 80.8% of the total discharge.