Unique atmospheric boundary layer structures driven by lake effects

Lakes affect regional climate by influencing heat and moisture exchange and near-surface wind. However, their global impact on the atmospheric boundary layer, a key layer of land–atmosphere interaction, remains unclear. Here, we combine satellite-based atmospheric profiles with the fifth generation European Centre for Medium-Range Weather Forecasts reanalysis to assess the impacts of large inland lakes (area greater than 500 square kilometers). Lakes enhance heat (1.6 degrees Celsius) and moisture (0.4 grams per kilogram) transport toward surrounding land, shifting low-level instability center to within 25 kilograms of the shoreline and strengthening turbulent mixing and convective development. Consequently, atmospheric boundary layer height over these lake-adjacent lands increases by 0.3 to 0.6 kilometers, while it remains lower over lakes because of stronger stratification. The dominant processes of lake effects vary with season, latitude, elevation and lake size. These findings underscore the importance of incorporating lake–atmosphere coupling into weather and climate models. Large inland lakes tend to increase the atmospheric boundary layer height over nearby land areas and reduce it over the lake itself, with the dominant mechanisms (thermal, moisture, and dynamic processes) varying with season, lake elevation, size, and latitude.