The structure of the turbulent atmospheric boundary layer is affected by the presence of thermal stratification. Brutsaert’s contributions to understanding and parameterizing such effects have had great impact in the field. We describe our efforts trying to parameterize thermal effects on atmospheric boundary layers in the presence of large wind farms using Large Eddy Simulation. As a first step, we examine the structure of passive scalar transport in the wind turbine array boundary layer (WTABL). Initial results from this project (performed in collaboration with Marc Calaf and Marc B. Parlange of EPFL, and funded by the National Science Foundation) will be presented.