Ensemble of models shows coherent response of a reservoir’s stratification and ice cover to climate warming

• Published in: Aquatic sciences Vol. 84; no. 4
• Main Authors: Feldbauer, Johannes, Ladwig, Robert, Mesman, Jorrit P., Moore, Tadhg N., Zündorf, Hilke, Berendonk, Thomas U., Petzoldt, Thomas
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.10.2022; Springer; Springer Nature B.V
• Subjects: Analysis; Aquatic resources; Biomedical and Life Sciences; Chemical reactions; Climate; Climate change; Climate models; Climate warming; Drinking water; Ecology; Environmental Management; Freshwater & Marine Ecology; Global warming; Ice; Ice cover; Lake ice; Lakes; Life Sciences; Marine & Freshwater Sciences; Model ensemble; Oceanography; Physical properties; Research Article; Reservoirs; Stratification; Surface temperature; Surface water; Trends; Uncertainty; Variance analysis; Water quality; Water reservoirs; Water stratification; Water temperature; Water temperature trend; Model ensemble; Climate warming; Stratification; Ice cover; Water temperature trend
• ISSN: 1015-1621; 1420-9055; 1420-9055
• DOI: 10.1007/s00027-022-00883-2

Water temperature, ice cover, and lake stratification are important physical properties of lakes and reservoirs that control mixing as well as bio-geo-chemical processes and thus influence the water quality. We used an ensemble of vertical one-dimensional hydrodynamic lake models driven with regional climate projections to calculate water temperature, stratification, and ice cover under the A1B emission scenario for the German drinking water reservoir Lichtenberg. We used an analysis of variance method to estimate the contributions of the considered sources of uncertainty on the ensemble output. For all simulated variables, epistemic uncertainty, which is related to the model structure, is the dominant source throughout the simulation period. Nonetheless, the calculated trends are coherent among the five models and in line with historical observations. The ensemble predicts an increase in surface water temperature of 0.34 K per decade, a lengthening of the summer stratification of 3.2 days per decade, as well as decreased probabilities of the occurrence of ice cover and winter inverse stratification by 2100. These expected changes are likely to influence the water quality of the reservoir. Similar trends are to be expected in other reservoirs and lakes in comparable regions.