冰川径流温度及其响应机制研究进展

在冰冻圈地区,受到积雪和冰川融水的影响,径流表现出独特的热状况,形成特有的冷水生态系统.由于大气和河流内部过程之间强烈的耦合和高敏感度,河水温度作为生态系统的重要驱动因素在冰川流域表现得尤为显著.通过对冰川径流温度特征、影响因素和热量机制响应等方面的国内外研究现状进行综述,发现冰川径流温度具有温度低、时空变化显著的特征;冰川径流温度影响因素主要有4个方面:水-气界面的热量传输、水-河道及河岸界面热量传输、径流组成、气候变化及人类活动;冰川径流热量机制的响应在河水物理化学性质方面表现为河流水质参数以及热量水分循环的影响,在河流水生生态系统方面表现为水生生态系统的分布和结构随冰川径流温度的变化而变化,且一旦超过某个阈值后,这种变化不可逆.

Recent advances in glacier-fed river stream temperature and responses research

Within the cryosphere, glacier-fed streams exhibit distinctive thermal regimes due to glacier melt influences; accordingly, these streams host a unique coldwater ecosystem. The role of water temperature as a driver of various intra-ecosystem processes is particularly significant in glacierized basins due to the strong coupling and high sensitivity between atmospheric and in-stream processes. In this paper, we review studies of the temperature characteristics in glacier-fed river streams, the influencing factors, and the response in aquatic ecosystems. Previous analyses have shown that glacial rivers are characterized by low temperatures and remarkable spatiotemporal temperature variations. Influencing factors in glacial rivers can be summarized in four major categories: heat transfer at the air-water interface, heat transfer at the water-channel interface, runoff components, and climate change and human activity. The response of a glacial river thermal regime to its physicochemical properties results in changes to the river water quality and thermo-hydrological fluxes. While the response of the aquatic ecosystem changes the distribution and structure of aquatic system with changing glacial stream temperature, once a certain threshold is exceeded, the change will be irreversible.