STRATIFIED ATMOSPHERIC BOUNDARY-LAYERS AND BREAKDOWN OF MODELS

The goal of this study is to assess complications in atmospheric stabl e boundary layers which are not included in numerical models of the st ably stratified boundary layer and to provide a formulation of surface fluxes for use in numerical models. Based on an extensive interpretiv e literature survey and new eddy correlation data for the stable bound ary layer, this study defines two prototype stable boundary layers: th e weakly stable case and the very stable case. The weakly stable bound ary layer is amenable to existing models. The very stable boundary lay er eludes modeling attempts due to breakdown of existing formulations of turbulence and due to features found in the atmosphere which are no t normally included in models. The latter includes clear-air radiative cooling, low-level jets, surface heterogeneity, gravity waves, meande ring motions, and other mesoscale motions which propagate from outside the local domain. While these mechanisms are not essential to underst anding idealized or laboratory versions of the stable boundary layer, they complicate comparisons of numerical models and theories with actu al atmospheric boundary layers. Statistics which describe various feat ures of the stable boundary layer are offered for future comparison wi th modeling results.