Modeling and Parameterizing the Ocean Planetary Boundary Layer

Abstract

The portion of a geophysical fluid that is directly influenced by the presence of a boundary is referred to as a planetary boundary layer, PBL. The two most notable examples are the atmospheric boundary layer, ABL, where the lower surface is either land or ocean, and the ocean’s surface boundary layer, OBL, bounded above by the atmosphere. Although the focus here is the OBL, it should become evident that the observational database is incomplete in some important ways and that the state of modeling is immature relative to that of the atmosphere. Therefore, in the absence of evidence to the contrary, ABL theory, observations and models are presented as being similar to the OBL. However, it is important to identify unique characteristics of the OBL. The ocean’s benthic boundary layer and its parameterization are the subjects of Beckmann (1998, this volume). Shallow coastal regions where the OBL and benthic boundary layer interact, and where ocean tidal mixing can be strong are excluded. Also excluded are ocean interior mixing processes, except when they interact with the OBL.