1966～2015年长江源冰川融水变化及其对径流的影响 ——以冬克玛底河流域为例

气候变暖改变了长江源的冰冻圈,影响了当地的生态系统。采用HydroGeoSphere（HGS）水文模型,对长江源区冬克玛底河流域冰川融水进行了模拟研究,以评估气候变暖背景下冰川融水径流对流域水资源的影响。利用研究区周围4个气象站点的资料,采用多元回归和插值方法重建了1966~2015年气象数据,并采用2005~2006年的实测流量数据对模型模拟结果进行了验证,表明模型有一定的可信度。结果显示：① 过去50 a,冬克玛底河流域的平均物质平衡为-151 mm/a,冰川物质累积亏损为7.55 m,温度升高对冰川的影响超过降雨增加的影响;② 物质平衡与降水呈现正相关,与正积温和冰川融水为负相关;③ 过去50 a,冬克玛底河流域总径流量、冰川区产流量、非冰川区产流量都呈现增加趋势,其中增加的总径流量的25%为降水增加所致,75%为气温升高导致冰川消融所致。研究结果可为气候变暖背景下长江源的保护提供一定的科学依据和参考。     

粘性土层井孔抽水试验的参数识别

粘性土层属于弱透水层,其水流、溶质运移和地球化学过程对于水文地质条件和环境变化具有重要意义.通过抽水试验来获取粘性土原位水力学参数是对粘性土水文地质问题进行研究的必要手段,但由于其渗透性很小,不能采用和常规含水层一样的方法求参.粘性土中的单孔抽水试验与一般含水层中的微水试验具有较大的相似性,因此可以借用微水试验的计算公...     

The influence of low-permeability cap on capillary pressure during pumping in unconfined aquifer

The pumping test in an unconfined aquifer with and without a low-permeability soil was studied experimentally to reveal the influence of the negative air pressure （NP） caused by the upper layer on the water content （w）, the water pressure （Pw）, as well as on the capillary pressure （Pc）. The study demonstrates that the NP generated in the vadose zone during pumping in the capper aquifer has a significant influence on w, Pw and Pc The Pc obtained from the capped aquifer is smaller than that without the upper layer. After the NP reaches a peak, the influence of the NP on Pc. is gradually declined as the air inflows through the upper layer which makes the NP gradually return to zero. When the air pressure returns to the atmospheric pressure, Pc in the vadose zone is only correlated with Pw, the same as the case with no upper layer.