Southeast Alaska High Resolution WRF: Hourly dynamically downscaled climate model simulations at 1- and 4-km spatial resolution for both historical (1981-2019) and future periods (2031-2060)

Southeast Alaska is a topographically complex region that is experiencing rapid rates of change with climate regimes that range from temperate rainforest to expansive glaciers and icefields. Global climate models – with a typical spatial resolution of 100 km – poorly resolve this area, while recent downscaling efforts have sought to improve upon existing deficiencies. This research produced hourly dynamically downscaled climate model simulations at 1- and 4-km spatial resolution for both historical (1981-2019) and future periods (2031-2060) across Southeast Alaska. Particular focus was placed on three key watersheds: 1) Montana Creek near Juneau, 2) Indian River near Sitka and 3) Staney Creek on Prince of Wales Island. The projected simulations were based on the representative concentration pathway 8.5 (RCP8.5) emissions scenario. The simulations included the historical Climate Forecast System Reanalysis, and two climate models (the Community Climate System Model, version 4 and the Geophysical Fluid Dynamics Laboratory Climate Model, version 3), which were both run for historical and future periods. All downscaling simulations were run using a 17-month spin-up period to sufficiently generate the land surface state and the lateral boundary conditions for each were updated every 6 hours to constrain the output. The downscaling was completed using the Weather and Research Forecasting Model, version 4.0.