Propagation of fronts and frontogenesis versus frontolysis over orography

Summary

Frontal propagation and its evolution over complex terrain features is not well understood. Moreover, one of the major sources of forecast error occurs over the earth's orography. This presentation reviews model studies of frontal interaction with smooth and relatively simple orographic profiles. Emphasis is placed on model predictions, of propagation speed and on the properties of the flow that favor either frontogenesis or frontolysis. The physical processes involved in the front-mountain interaction are isolated, with the aim of providing a basic physical understanding of the interaction process that may be used in the interpretation of more realistic but more complex flow models. Considered are bot homogeneous and density stratified fluid, both two- and three-dimensional orographic features, and both filtered (geostrophic and semigeostrophic) and unfiltered flow models. Potentially important areas of research that may add to knowledge of front-mountain interactions are briefly explored.