青藏高原冰川和湖泊广布,湖泊水质、沉积物对冰川变化的响应研究较为匮乏.本文通过藏东南外流区第二大湖泊然乌湖监测的系统设计,研究了湖泊对冰川的响应程度.利用水位计对比然乌湖和各大补给河流水位与水温的关系,发现冰川融水补给河流(曲尺河)对湖泊水量平衡的重要性;利用水质多参数仪器定期监测湖泊和河流的水质参数的时空变化,发现冰川融水对然乌湖温度的时空变化有重要影响,导致水温自上而下降低,流量小的季节湖泊温度差异变小;自上游到下游电导率逐渐升高,显现出离子浓度低的冰川融水对湖泊的冲淡效应,p H随之变化;甚至影响到了叶绿素含量的时空变化;利用在上、中和下湖布设的沉积物捕获器监测沉积通量的时空变化,发现沉积速率非常大,通量具有上湖〉中湖〉下湖的规律,且时间上各湖具有入湖流量大的季节大于小的季节的规律,说明了冰川融水对然乌湖在沉积量方面的影响是决定性的.总之,然乌湖水体和沉积物能够高信度地响应上游冰川的变化,然乌湖沉积物具有高分辨率反演该区域冰川和气候变化的潜力.
Vast lakes and glaciers are distributed across the Tibetan Plateau. However, the study of the response of lake water quality and sediment to glacier variation is relatively deficient. Ranwu Lake is the second largest lake in the outflow arealn SE Tibet. This paper monitored the degree of response of the lake to glaciers. Glacier melt influenced the lake directly, which is illustrated by the fact that the Quchi River, the largest inflow and a glacier melt river, dominates many aspects of the lake, including the water level, seasonal and spatial water temperature, conductivity, pH, and even chlorophyll a content. Depositional flux analysis measured by sediment traps showed that the fluxes decrease from the upper to the lower lake with a greater flux in the summer than during other seasons, reflecting the dominant influence of Quchi River on the lake. To conclude, the waters and sediment of Ranwu Lake clearly respond to the glacier variation. The sediment in Ranwu Lake has great potential to reflect variations in the nearby glaciers with high temporal resolution.