Irregular changes in lake surface water temperature and ice cover in subalpine Lake Lunz, Austria

Abstract

Evidence is growing that the surface water temperature increases and the duration of ice cover has decreased in many lakes worldwide during the past few decades. Here, we present changes in surface water temperature and ice-cover duration of Lake Lunz from 1921 to 2015 and evaluate how fast these changes occur over time, in particular with respect to other lakes with similar long-term data series. Since 1921, the surface water temperature of this Austrian subalpine lake has increased by 0.8 °C, with the most intense increase recorded during the spring and summer months (~1-2 °C) and less during fall (~0.3 °C). The duration of full lake ice cover has decreased significantly since and 2015 this interannual variability increased by almost 4 times. Thus, the observed decrease of ice cover is accompanied by increasing interannual variability, during which the lake was fully ice covered. When comparing days of full ice cover to other lakes until 2005, Lake Lunz had a similar decline in ice-cover duration (1.85 d/decade), but a dramatic decrease in full ice cover during 2005 and 2015 indicates that the overall decline in lake ice-cover duration was sensitive to changes in lake ice cover during the past decade. This study emphasizes the importance of continuous and collaborative measurements in other (subalpine) lakes worldwide to test, and also manage, the sensitivity of lakes to ongoing effects of climate change.

The ice regime of Lake Ostrzyckie (Kashubian Lakeland, northern Poland)

“…However, there were winters (in 2006 and 2013) without any ice cover observed there. The ice regime of Lake Lunz has mainly been modified by a rise in air temperature that has been recorded in the last few years (Kainz et al 2017). This is also agrees with the research by Franssena and Sherrer (2008) who analysed the ice regimes of 11 lakes situated in the Swiss plateau and stated that ice cover duration has changed as the air temperature in winter is higher than it used to be.…”

“…2014). However, in the case of a lack of such data, other long-term periods are used Ptak et al 2019;Nowak et al 2018;Kainz et al 2017;Lei et al 2012;Soja et al 2014) in order to determine the ice regimes of selected lakes, which are largely affected by climate change (Smekhtin 2017).…”

Variability and course of occurrence of ice cover on selected lakes of the Gnieźnieńskie Lakeland (Central Poland) in the period 1976–2015

“…Changes in ice cover on Lake Superior over 150 years were evident: the beginning of development of ice cover occurred later by an average of 1.6 day·dec -1 , and its end earlier by an average of 1.7 day·dec -1 [11]. In the case of Lake Lunz (Austria), Kainz et al [12] observed a reduction of duration of ice cover, and the average rate of the phenomenon amounted to 1.85 day·dec -1 . In research on Lake Mendota (USA), Magee et al [13] found that the development of ice cover occurred 9 days per century later, and its disintegration occurred 12.3 days per century earlier, resulting in a decrease in duration of ice cover (by 21.3 days per century).…”

Effect of Environmental Conditions and Morphometric Parameters on Surface Water Temperature in Polish Lakes

“…The considerable effect of water exchange in the river-lake system on the temperature of lake waters has been emphasised by, among others, Vinnä et al [76] and Ptak et al [77]. Kainz et al [78], analysing changes in water temperature and ice phenomena in Lake Lunz (Austria), found that a short retention time causes a more dynamic heat budget in comparison to lakes with longer retention times. All lakes analysed in the study have a flow-through character, but due to their morphometric parameters and size of rivers, the rate of water exchange is variable.…”