Boundary Layer, Urban Meteorology and Land-Surface Processes
Gradient-based similarity theory of the stably stratified boundary layer
Department of Physics, Marquette University, Milwaukee
23 April 2012, 4:00 PM
National Weather Center, Room 5930
120 David L. Boren Blvd.
University of Oklahoma
Weak turbulence in very stable conditions limits the validity of the Monin-Obukhov similarity, regarded as the major tool for understanding near-surface turbulence. The similarity predictions for gradients are formally valid only in sub-critical cases. Similarity functions cannot be accurately estimated during very stable stratification due to the uncertainty introduced by small values of fluxes, and also due to serious self-correlation errors. During my talk, I will introduce another approach, by defining three gradient-based scaling systems for the stably stratified boundary layer. I will examine them by using data collected during the SHEBA field program in the Arctic. The resulting similarity functions for fluxes and variances will be presented in an analytical form, which is expected to be practically unaffected by self-correlation in very stable regime. I will also show how the similarity functions in the surface layer can be modified and extended for the entire stable boundary layer. The modification does not alter the dependence of similarity functions on the Richardson number, and is supported by data collected during the Cooperative Atmospheric-Surface Exchange Study-1999 (CASES-99).