Drainage flow over undulating terrain

The present work investigates drainage events of cold air that occur over an undulating terrain, with elevations differences of some tens meters and grassy surface. For this, data collected in the autumn of 2015 from a micrometeorological tower and four weather stations are used. The results show two different cases of drainage, one when the ambient flow is upslope against the near the surface drainage flow, and another when the ambient flow is downslope in favor of the drainage.