Valley wind systems have been extensively studied and results reported in the literature. These studies usually involved winds near ground level in narrow, well defined valleys. This paper presents results of a unique observational study into terrain effects at 400 m above ground in an ill defined valley which is about 80km wide.
Over 2300 pilot balloon observations made from 1975 to 1978 inclusive were compared to 1200m geostrophic wind data extracted from 850 mb pressure charts. Comparisons demonstrated that air flow at industrial plume levels is subject to valley channeling which is especially strong in winter months.