Boundary Layer, Urban Meteorology and Land-Surface Processes

Quasi-universal scaling of boundary-layer wind speeds in mesoscale regime

Dr. Sukanta Basu

Department of Marine, Earth, and Atmospheric Sciences
North Carolina State University

25 March 2016, 2:00 PM

National Weather Center, Room 5600
120 David L. Boren Blvd.
University of Oklahoma
Norman, OK

Recently, we analyzed long-term wind speed time-series from several field sites, including Boulder (USA), Cabauw (the Netherlands), Høvsøre (Denmark), and FINO1 (the North Sea), up to a height of 300 m from the ground. To characterize scaling in the mesoscale regime, we invoked the so-called extended self-similarity (ESS) framework. We found that the ESS holds for all the datasets, and remarkably, the scaling exponents corresponding to the mesoscale range closely match the well-accepted inertial-range turbulence values. During this presentation, we will attempt to heuristically explain these intriguing results. We will show that the pdfs of wind speed increments are well described by the Normal Inverse Gaussian (NIG) distributions. Furthermore, we will analytically prove that the ESS results essentially signify a unique scaling trait of two key parameters of the NIG distributions. Finally, we will discuss the performance of various WRF-PBL schemes in capturing the observed ESS behavior.

Boundary Layer, Urban Meteorology and Land-Surface Processes Seminar Series website