STABLE BOUNDARY-LAYERS - OBSERVATIONS, MODELS AND VARIABILITY .1. MODELING AND MEASUREMENTS

Selected field measurements of evening stable boundary layers are pres ented in detail comparable with published Large Eddy Simulation result s. Such models appear to match idealized theories more closely than do some boundary-layer observations. Any attempt to compare detailed obs ervations with idealized models therefore highlights the variability o f the real boundary layer. Here direct turbulence measurements across the stable boundary layer from a heterogeneous and an 'ideal' site are contrasted. Recommendations are made for the information needed to di stinguish 'heterogeneous' and 'ideal' cases. The companion paper (Part II) discusses further the issues of data, analysis in the presence of variability, and the effects of averaging over heterogeneous terrain.