Modeling of Effects of Climate and Land Cover Change on Thermal Loading to Puget Sound

Thursday, 18 December 2014
Qian Cao1, Ning Sun2, John R Yearsley2, Bart Nijssen2 and Dennis P Lettenmaier3, (1)University of California Los Angeles, Geography, Los Angeles, CA, United States, (2)University of Washington, Seattle, WA, United States, (3)University of California, Los Angeles (effective Nov., 2014), Dept. of Geography, Los Angeles, CA, United States
We apply an integrated hydrology-stream temperature modeling system, DHSVM-RBM to examine the response of riverine thermal loading to Puget Sound as affected by land cover and climate change. We represent the 15 major river basins and the discharge and temperature of the streams that drain them. DHSVM-RBM integrates the Distributed Hydrologic Soil Vegetation Model (DHSVM) which represents the hydrologic response (river discharge) of the basins with the distributed stream temperature model RBM, which represents thermal dynamics of the streams at high temporal and spatial resolutions. We first show that the model construct is able to represent observed historic streamflow and stream temperature variations at sub-daily, seasonal, and interannual time scales. We find that the thermal load to Puget Sound varies season to season, increasing in fall and winter and decreasing in spring and summer compared with long-term base temperature. The estimated annual thermal load is around 2791 cms·K, accounted for mostly by the Skagit and Snohomish Rivers. We also explore the relative effect of projected future climate and land cover change on Puget Sound riverine thermal loadings.