Can mesoscale climate models help with hydroclimate forecasts?

Working with Alan Hamlet (Asst. Prof. of Civil and Env. Engineering at UW), with Eric Salathe (Climate Impacts Group at UW), and with graduate student Malena Foster, we are examining what components of mesoscale climate models can aid in hydroclimate forecasts. This research is sponsored by the National Science Foundation.

Currently the quality of meteorological driving data sets in mountain environments is a major obstacle to characterizing the sensitivity of particular watersheds and simulating climate related impacts using hydrologic models. In particular, accurately characterizing where precipitation falls as rain vs. snow on an event basis, and when and how fast snow melts is essential to the assessment of climate sensitivity at small to medium (10-1000 km2) spatial scales. Errors in precipitation, temperature and radiative data sets in mountain environments are related to the scarcity of high elevation measurements, poor measurement quality due to adverse conditions, relatively few measured variables, and interpolation errors in complex terrain.

Because the density of in situ data will always be less than ideal for most watersheds, we are developing and evaluating new methods for combining physical process-based information from meso-scale climate models with low elevation meteorological stations and high resolution topographic information to remap available meteorological driving data more accurately across complex terrain. The performance of meso-scale climate models in this application is currently poorly understood, and we will use the intensively-monitored Tuolumne and North Fork American River watersheds in the Sierra Nevada, California to develop, evaluate, and refine these new techniques at basin scales ranging from 10 to 800 km^2. While specific research experiments will focus on these two mountain watersheds in the western United States, the research is designed to develop and evaluate tools that will be broadly applicable in mountain environments across the western U.S. and potentially at the global scale.

The following research questions will be addressed: