Improved Parameterization of Stably Stratified Boundary Layer Turbulence in Atmospheric Models

摘要

In the course of the project, our research has spanned over several areas encompassing theoretical, numerical and phenomenological aspects of stably stratified atmospheric boundary layers (SBLs). We have laid a solid foundation for studying stably stratified turbulence in the framework of a Quasi-Normal Scale Elimination theory (QNSE) developed by us. We consider the QNSE theory as a major breakthrough in this field. Being maximally proximate to the first principles, the theory penetrates very deeply into the physics of anisotropic turbulence and turbulence-wave interaction yet its calculations can be carried out analytically almost to the final results. We have performed initial analytical exploration of the new theory and implemented it in Reynolds- averaged, Navier-Stokes (RANS) models whose predictions agree well with data collected in BASE and SHEBA campaigns. In addition, we investigated non-local features of stable planetary boundary layers (PBLs) caused by semi-organized structures overlooked in traditional boundary-layer meteorology and in PBL schemes currently used in atmospheric models. Theoretical developments focused on basic length scales characterizing semi-organized structures and corresponding revision of classical similarity theory, PBL depth equations, and bulk resistance and heat/mass transfers laws.