Comparison of Boundary Layer Heights in the Columba River Gorge and Basin form Wind Profiling Radars and Numerical Weather Prediction Models during WFIP2

The Second Wind Forecast Improvement Project (WFIP2) is a DoE- and NOAA-sponsored program whose goal is to improve the accuracy of numerical weather prediction (NWP) forecasts in complex terrain. WFIP2 consists of an 18-month (October 2015 – March 2017) field campaign held in the Columbia River gorge and basin, in the Pacific Northwest of the U.S. As part of WFIP2 a large suite of in-situ and remote sensing instrumentation has been deployed, including, among several others, a network of eight 915-MHz wind profiling radars (WPRs), and many surface meteorological stations.

The diurnal evolution and annual variability of the boundary layer height in the WFIP2 area is investigated using WPRs, employing state-of-the-art automated algorithms. The results are used to evaluate possible errors in the Rapid Refresh (RAP) and High Resolution Rapid Refresh (HRRR) models in this area of complex terrain. Preliminary results show that: high-resolution model versions do better at estimating maximum boundary layer height than low-resolution versions; during cloud free days NWP models boundary layer height estimations are better; and NWP models estimates of the rate of growth of boundary layer height are more accurate than model estimates of the rate of decay. Also, boundary layer heights estimated by WPRs are used to look at different diagnostic definitions of the boundary layer in the NWP models.

The final goal is to help guiding improvements to the boundary layer parameterizations.