92nd American Meteorological Society Annual Meeting (January 22-26, 2012)

Wednesday, 25 January 2012
Simulated Chinooks' Sensitivity to Resolution and Model Configuration At Cold Regions Test Center, Alaska
Jason C. Knievel, NCAR, Boulder, CO; and J. A. Grim, C. M. Witt-Schulte, and D. P. Wozniczka

Chinooks, foehns, and similar down-slope winds can abruptly change many atmospheric conditions in the lee of mountains, such as temperature, humidity, pressure, cloudiness, precipitation, air quality, visibility, and, most obviously, wind speed and direction. At the test ranges of the Cold Regions Test Center north of the Alaska Range, changes in temperature are usually the most critical to the Center's mission.

For many reasons, chinooks are not easy to simulate with numerical models. These reasons included the scales of forcing involved, the high local gradients that characterize them and the differences in size and shape of actual versus model-estimated topography. Experience suggests that accurate forecasts of chinooks rest heavily on the experience and intuition of forecasters, and on diagnostic techniques that employ observations.

Our presentation will explore whether improvements in operational forecasts of chinooks in Alaska can be gained by increasing the resolution of a numerical prediction system, optimizing its configuration, modifying the lower boundary condition, or through other practical means. In the process we will explore the physical details of several cases of Alaskan chinooks.

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