Climate sensitivity of Sierra Nevada Lakes

We analyzed the thermal response in the upper mixed layer of a lake in the Sierra Nevada of California to interannual variation in air temperature, snow deposition, and other climate factors to characterize relative effects on water temperature. We then use summer temperature data from 19 lakes to understand how the relative importance of snow and other factors governing lake temperature vary at broad spatial scales and predict sensitivity to warming in over 1600 lakes across the region. Our study has three specific objectives: 1) to characterize how water temperatures in mountain lakes are responding to variation in air temperature, snow deposition, and other climate factors; 2) to evaluate scaling relationships for water temperature using landscape and lake morphometric attributes; and 3) using those scaling relationships, to identify lakes that are most sensitive to warming from ongoing changes in climate. Our results emphasize the high rate of climate warming taking place in mountain ecosystems, and demonstrate the substantial role of snowpack in governing lake temperature. We illustrate the extent to which warming within lakes scales with elevation and lake morphometric attributes, and use those empirical relationships to identify lakes most sensitive to ongoing changes in climate.