Large-scale modeled contemporary and future water temperature estimates for 10774 Midwestern U.S. Lakes

Abstract

Climate change has already influenced lake temperatures globally, but understanding future change is challenging. The response of lakes to changing climate drivers is complex due to the nature of lake-atmosphere coupling, ice cover, and stratification. To better understand the diversity of lake responses to climate change and give managers insight on individual lakes, we modelled daily water temperature profiles for 10,774 lakes in Michigan, Minnesota, and Wisconsin for contemporary (1979-2015) and future (2020-2040 and 2080-2100) time periods with climate models based on the Representative Concentration Pathway 8.5, the worst-case emission scenario. In addition to lake-specific daily simulated temperatures, we derived commonly used, ecologically relevant annual metrics of thermal conditions for each lake. We include all supporting lake-specific model parameters, meteorological drivers, and archived code for the model and derived metric calculations. This unique dataset offers landscape-level insight into the impact of climate change on lakes.

Figure 1. Large-scale lake modeling and metric calculation pipeline.

Steps include (a) processed meteorological drivers and lake attributes linked to lakes. (b) General Lake Model v2.2 model run using lake meteorology and lake attributes to parameterize model and (c) daily temperature profiles and calculated thermal metrics archived.

Figure 2. Spatial and temporal distribution of ice and water temperature validation data.

Ice observations (a,c) and water temperature (b,d) observations used in this study had different temporal and spatial distributions and represent an aggregate across multiple source databases.

Figure 3. Observed versus modeled temperature for the full three-state validation dataset (3,952 lakes).

(a) All individual temperature observations (decimated to 10% of full population for improved visualization), (b) epilimnetic average temperatures (during stratified periods only) and (c) hypolimnetic average temperatures.

Figure 4. Observed versus modeled ice on and off for all 29 Wisconsin lakes (1,272 observations).

Ice onset (a) and ice breakup (b) dates represented as day of year. Day of year for ice on can be greater than 365 because 365 was added to events that occurred in January or February to create a continuous dataset.