Spatial evaluation of high-resolution wind fields from empirical and dynamical modeling in hilly and mountainous terrain.

Empirical high-resolution (100 m × 100 m) surface wind fields were intercompared withdata from the non-hydrostatic regional climate model COSMO-CLM (3 km resolution) andwith wind field analysis data from the Integrated Nowcasting through ComprehensiveAnalysis (INCA) system (1 km resolution), using hourly temporal resolution (Schlager et al.,2018). The empirical wind fields were generated, using the CALMET diagnostic model, for tworegions with dense meteorological station networks: The WegenerNet Feldbach Region(FBR; Kirchengast et al., 2014) and its alpine sister network, the WegenerNet Johnsbachtal(JBT). The high-density WegenerNet FBR is located in southeastern Styria, Austria, a regionpredominated by a hilly terrain and limited differences in elevations. The network consists of155 meteorological stations, located within an area of about 22 km × 16 km (one station per∼2 km2), observing temperature, humidity, precipitation, wind, soil moisture, and otherparameters, at a temporal resolution of 5-minutes. The WegenerNet JBT is located in amountainous region in northern Styria and contains 11 meteorological stations distributedover an area of about 16 km × 17 km and elevations ranging from about 600 m to2200 m. The focus of the presented work lies on evaluating spatial differences and displacementsbetween the different datasets for thermally induced and strong wind events. For thisintercomparison, a neighborhood-based spatial wind verification methodology, the so-calledWind Fractions Skill Score (WFSS), is used to estimate the modeling performances.Furthermore, gridpoint-based statistical error measures were calculated for the sameevaluation events. The spatial verification indicates a better statistical agreement for the hilly WegenerNetFBR than for the mountainous WegenerNet JBT. The results for the WegenerNet FBR show abetter agreement between INCA and WegenerNet than between COSMO and WegenerNetwind fields, especially for large scales (neighborhoods). In particular, COSMO-CLM clearlyunderperforms in case of thermally induced wind events. For the JBT region, all spatialintercomparisons indicate little overlap at small neighborhood sizes. Considerable biases ofwind vectors occur between INCA and WegenerNet as well as between COSMO and INCA.It is shown that COSMO-CLM, with a limited horizontal resolution of 3 km ×3 km and hence a too smooth orography, is not able to represent small-scale windpatterns.References:Kirchengast, G., T. Kabas, A. Leuprecht, C. Bichler, and H. Truhetz (2014): WegenerNet: Apioneering high-resolution network for monitoring weather and climate. Bull. Amer. Meteor.Soc., 95, 227–242, doi:10.1175/BAMS-D-11-00161.1.Schlager, C., G. Kirchengast, J. Fuchsberger, A. Kann, and H. Truhetz (2018): A spatialevaluation of high-resolution wind fields from empirical and dynamical modeling in hilly andmountainous terrain. Geosci. Model Dev. Discuss., 1–26, doi:10.5194/gmd-2018-238 [ABSTRACT FROM AUTHOR]