Nested Model Simulations of Regional Orographic Precipitation. Global ClimateChange Response Program

摘要

The Bureau of Reclamation (Reclamation) evaluated a nested modeling systemapproach to the simulation of regional and local-scale precipitation for water resources management applications. Comparisons with high elevation snow telemetry sites in the Gunnison Basin of the Colorado River headwaters showed reasonably accurate simulations of cumulative precipitation from October to mid-May; however, spring and summer precipitation was significantly overpredicted. High resolution, nonhydrostatic Clark model results are physically plausible and simulate important physical controls of convective precipitation that is highly constrained by local, topographic interactions with airflow. The effects of the Sierra Nevada on the rain/snow line and zones for maximum prcipitation appear reasonably simulated. These sensivity studies suggest that the numerical stability and accuracy of these types of models provide quantitative precipitation forecasts of value to the water resources management community.