Field studies of stable air flow over and around a ridge

Three different field experimental techniques (smoke timelines, tetroon flights, and plume photography) have been used to examine the stable air flow field over and around a ridge. All of the data obtained from these field experiments are shown to be in good agreement with a two-layer model. It is also shown that the data obtained in the upper of the two layers, which flows over the terrain, fit well with a simple potential flow model. The ridge is reasonably two-dimensional with a length-to-width ratio of about 5. These field data for this fairly long ridge are found to be in much better agreement with laboratory data (available in the published literature) for axisymmetric hills rather than those for two-dimensional barriers with gaps.