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

Wednesday, 25 January 2012
An Investigation of Boundary Layer Parameterizations in a Simulated Low-Level Jet Observed During the Wind Forecast Improvement Project
Hall E (New Orleans Convention Center )
Joseph B. Olson, CIRES/Univ. of Colorado, Boulder, CO; and J. M. Brown, R. M. Banta, Y. L. Pichugina, J. M. Wilczak, J. D. Mirocha, and C. A. Finley

The prediction of winds in the lowest 200 m of the atmosphere is crucial for the design, operation, and maintenance of wind farms. The lack of standard observations in this layer makes the development and verification of numerical weather prediction models difficult for wind energy applications. The Wind Forecast Improvement Project (WFIP) is a collaborations between the National Oceanic and Atmospheric Administration (NOAA) and the Department of Energy (DOE) as well as two private sector groups, WindLogics and AWS Truepower. A primary goal of WFIP is to fill the void in observations of the lower atmosphere by deploying a regional network of remote sensing observing systems, along with existing tower and nacelle anemometer data in the upper Midwest and Texas. With this concentrated data source, efforts towards planetary boundary layer (PBL) scheme development can be focused on improving the wind forecasts at heights important for wind energy applications.

Several Intensive Operating Periods (IOPs) have been identified in order to isolate specific processes important for wind farm operators, such as low-level jets and ramp events associated with convective outflow. Tests were performed within the framework of a high-frequency data assimilation system, the Rapid Refresh (RR) and a much higher-resolution nest (HRRR). The RR and HRRR forecast model component is the Advanced Research version of the Weather Research and Forecasting model (WRF-ARW) and utilizes the Mellor-Yamada-Janjic PBL scheme. This standard configuration will be tested along with other PBL schemes to assess the model skill at forecasting low-level winds. Further tests are performed to assess the sensitivty of important parameters of the PBL schemes, such as PBL height, mixing lengths, and closure constants. High-resolution model simulations are compared with wind measurements from profilers, lidar and towers throughout the region.

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