New Publication - The Impact of Lakes in North American Regional Climate Simulations
Mahdinia, M., Erler, A. R., Ng, K. H., Huo, Y., & Peltier, W. R. (2026). The Impact of Lakes in North American Regional Climate Simulations. Journal of Climate. https://doi.org/10.1175/jcli-d-25-0146.1
We are pleased to share a recent publication by Mani Mahdinia, Andre R. Erler, Ka Hei Ng, Yiling Huo, and W. Richard Peltier, titled "The Impact of Lakes in North American Regional Climate Simulations." The paper was recently published in the Journal of Climate.
The study investigates how lakes influence regional climate across North America using the Weather Research and Forecasting (WRF) model coupled with three different lake models. By comparing simulations with and without lakes over a 40-year period, the researchers demonstrate that lakes play a much larger role in regional climate than previously understood.
The simulations show that lakes can cool surrounding surface temperatures by up to 2.5 K and increase annual precipitation by as much as 25%, although the Great Lakes can reduce summer precipitation due to cooler lake surfaces and reduced evaporation. The study also found that lakes influence regional weather patterns by favoring cyclone development during the cold season and can amplify local climate change signals, highlighting the importance of accurately representing lakes in regional climate models.
This research supports the broader goals of the Canada1Water (C1W) project by improving our understanding of how lakes interact with the atmosphere and influence Canada's water cycle. As Canada's first fully integrated model of the national water cycle, C1W relies on accurate representations of surface water processes to better predict future water availability and the impacts of climate change. Improving the representation of lakes helps strengthen regional climate projections and provides a more robust scientific foundation for assessing future changes to precipitation, evaporation, and water resources across Canada.
Abstract
The primary objectives of this research are to: (1) assess the efficacy of three column lake models within a regional climate simulation context and (2) determine the influence of North American lakes on regional climate patterns. Regional climate modeling was performed using the Weather Research and Forecasting (WRF) model, coupled online with three different lake models. Simulations spanned the period 1979–2019 at a 24 km horizontal resolution, employing ERA5 reanalysis for initial and boundary conditions. The simulated temporal and spatial distributions of lake surface ice cover and temperature, including ice-in and ice-out dates, were validated against observational datasets. The relative performance of the lake models in reproducing these variables was evaluated. The results indicate that model performance is context-dependent, with no single model consistently superior across all simulated aspects. To explicitly quantify the impact of the lakes, a simulation without lakes was conducted. This analysis revealed a general cooling effect of lakes, reaching up to 2.5 K, and an increase in local precipitation, up to 25 %, on an annual basis. However, for some of the larger lakes, such as the Laurentian Great Lakes, a reduction in summer precipitation was also observed. This effect is attributed to the thermal stabilization induced by the cooler lake surfaces and a decrease in evaporation. An examination of lake enhancement of the climate change signal was conducted by using Mann-Kendall tests. The impact of lakes on cyclone/anticyclone activity was also investigated.
Citation
Mahdinia, M., Erler, A. R., Ng, K. H., Huo, Y., & Peltier, W. R. (2026). The Impact of Lakes in North American Regional Climate Simulations. Journal of Climate. https://doi.org/10.1175/jcli-d-25-0146.1