Moving Beyond Monin-Obukhov Similarity Theory in Modelling Wind Speed Proles in the Stable Lower Atmospheric Boundary Layer

Monin-Obukhov similarity theory (MOST) is commonly used to model the wind speed profile at altitudes relevant to wind power production (e.g. 10 to 200m). Though reasonably accurate for unstable to

weakly stable stratication, this approach becomes less inaccurate under increasingly stable stratification, largely due to the constant flux surface layer assumed by MOST becoming shallower. Furthermore, above the surface layer, the Coriolis force has a considerable influence on the wind speed prole (in particular in the formation of low-level jets) which cannot be modelled using similarity theory. The goal of this study is to quantitatively assess the breakdown of the MOST wind speed prole model within the bottom 200m

of the atmosphere under increasingly stable stratification and to explore alternative simplified models that are more accurate and physically appropriate. Using data from the 213m Cabauw meteorological tower in the Netherlands, it is shown that a two-layer MOST-Ekman model outperforms MOST for all stratifications.