OBSERVATIONS OF SIMILARITY THEORY STABILITY CORRECTION TERMS FOR MOMENTUM AND TEMPERATURE, ψ_m and ψ_h, OVER AGRICULTURAL FIELDS AND FORESTS

摘要

Equations 1-3 are found in almost all models of atmospheric flow in which the earth's surface is important. Most of the data used to develop the ψ functions came from experiments performed over very flat, homogenous terrain. This was appropriate initially because the original M-O theory was considered valid only under assumptions of an ideal surface. However modern practice is to apply similarity scaling in models of continental scale, including areas where the terrain and ground cover are anything but flat and continuous. Because of the importance of similarity theory, it is prudent to examine the experimental basis for frequently used forms of ψ_(m,h) when new data become available. This was done recently by Nakamura and Mahrt (2001), who looked at ψ_m over a boreal forest, at Euroflux sites, and over cotton fields and vineyards in California. In this study, we will examine values of ψ_(m,h) observed over four "non-ideal" sites, and compare them with predictions of two models, by Paulson (1970) and Byun (1990). The Byun model is slightly modified based on suggestions by Pleim (personal communication).