ABSTRACT

Arctic lakes are exposed to warming during increasingly longer ice-free periods and, if located in glaciated areas, to increased inflow of meltwater and sediments. However, direct monitoring of how such lakes respond to changing environmental conditions is challenging not only because of their remoteness but also because of the scarcity of present and previously observed lake states. At the glacier-proximal Lake Tarfala in the Kebnekaise Mountains, northern Sweden, temperatures throughout the water column at its deepest part (50 m) were acquired between 2016 and 2019. This three-year record shows that Lake Tarfala is dimictic and is overturning during spring and fall, respectively. Timing, duration, and intensity of mixing processes, as well as of summer and winter stratification, vary between years. Glacial meltwater may play an important role regarding not only mixing processes but also cooling of the lake. Attribution of external environmental factors to (changes in) lake mixing processes and thermal states remains challenging owing to for example, timing of ice-on and ice-off but also reflection and absorption of light, both known to play a decisive role for lake mixing processes, are not (yet) monitored in situ at Lake Tarfala.

摘要

北极湖在越来越长的无冰时期会遭受变暖的影响，如果位于冰川地区，则会增加融水和沉积物的流入。但是，直接监测此类湖泊如何应对不断变化的环境条件不仅具有挑战性，而且还因为目前和以前观测到的湖泊状态稀缺而具有挑战性。在2016年至2019年之间，在瑞典北部凯布耐卡兹山脉的冰川最近的塔法拉湖上，获得了最深处（50 m）整个水柱的温度。这一三年的记录表明塔法拉湖是两极分化的，并在此期间倾覆。春天和秋天分别。混合过程的时间，持续时间和强度，以及夏季和冬季的分层，在几年之间会有所不同。冰川融水不仅在混合过程中起着重要作用，而且在湖泊降温方面也起着重要作用。由于例如冰上和冰下的时间以及光的反射和吸收，外部环境因素对（混合）湖泊混合过程和热状态的变化仍然具有挑战性，众所周知，这两个因素对湖泊混合起着决定性的作用。尚未对塔法拉湖进行现场监控。