FUTURE CHANGES IN WATER AND NUTRIENT FLUXES FROM GLACIER WATERSHEDS IN ALASKA

Runoff from glaciers can significantly modify the quality, quantity, and timing of streamflow. The 90,000 km2 of glaciers in Alaska and the Yukon are currently experiencing some of the highest rates of ice loss on earth. These changes in glacier volume have profound implications for the hydrology and biogeochemistry of glacial watersheds and downstream near-shore marine ecosystems. We are investigating how climate change will impact glacier mass balance, streamflow, and riverine material fluxes for glacial watersheds in southeast Alaska. To evaluate future changes in glacier runoff, we used a temperature-index model that includes potential direct solar radiation and is calibrated for each glacier based on recent mass balance and discharge data. Future scenario RCP6.0 CCSM4 simulations are downscaled to 5-10 km resolution over the study area with the Weather Research and Forecasting (WRF) model. Finally, glacier runoff projections until the year 2100 are paired with contemporary time series data on solute concentrations at the glacier outflows to estimate how changes in glacier discharge will alter riverine biogeochemical fluxes of C, N, P, and Fe over the coming century.