New dynamical downscaling techniques garner attention

climate divisions

A group of AK CASC-affiliated researchers has achieved some success in their efforts to downscale past climate profiles in and around Alaska. Based on a wide variety of coarse-resolution historical data, those in the climate science community, as well as the public, now have an array of new visualization and forecasting tools available. Further, this work has increased the national profile of the AK CASC and related organizations at UAF.

Downscaling, a class of research methods that adds greater precision and detail to historical data and future projections has long held potential for Alaska and the Arctic, a region with a distinct—but sparse—climatic record. Along with others, Uma Bhatt, Peter Bieniek, and John Walsh have conducted a variety of studies in recent years, yielding some important validations regarding our climate, as well as some revelations.

Bieniek, for example, has found that the climatic conditions of Alaska’s “Interior,” as many familiar with the area understand them, actually extend further south than assumed, and that southeast Alaska actually has many more distinct climate zones than had been previously identified. In work led by Bhatt, the AK CASC and the Alaska Center for Climate Assessment and Policy (ACCAP) have further undertaken a model-based dynamical downscaling project for all of Alaska. This project makes use of the Weather Research and Forecasting (WRF) regional climate model, meant to establish greater complexity for Alaska climate simulations for the post-1979 period, and into the 21st-Century.

Until recently, climate downscaling in Alaska had been focused on terrestrial areas. But Walsh, whose work has long focused on Arctic sea ice, used downscaling techniques to establish a long-term sea ice database. For this project, in conjunction with NOAA, Walsh’s group used downscaling to determine the extent to which sea ice losses are due to warming water temperatures, establishing a common-format background for sea ice levels back to the 1920s. This work provides important new data relevant to offshore and coastal locations impacted by variations in surface temperature, winds, and sea ice.

In addition, in conjunction with this offshore and coastal downscaling work, and in partnership with the Alaska Ocean Observing System (AOOS) and the Scenarios Network for Alaska and Arctic Planning (SNAP) Walsh’s group developed a suite of web-based, searchable data tools for accessing downscaled data. Interfaces allow a user to select a variety of climate variables for plots of frequency of occurrence over time, as well as searching the historical Sea Ice Atlas for visual mapping of how Arctic sea ice off the coast of Alaska has changed over the last 90+ years.