A Numerical Investigation of the Influence of Large-Scale Winds on Sea-Breeze- and Inland-Breeze-type Circulations

Abstract

A two-dimensional mesoscale model is used to study the influence of large-scale background winds on sea-breeze- and inland- (vegetation) breeze-type circulations. It is found that the intensity (vertical velocity) of the sea breeze is at its maximum when the Propagation speed of the sea-breeze front is canceled out by the background wind speed. Using the gravity current theory, we get a fair prediction of this optimum background wind value. The intensity and extent of the inland breeze, forming between a forecast and an adjacent crop area, do not vary over a large range of values for the large-scale wind. The location of the ascending branch of the inland breeze is stationary with respect to the interface between the two vegetation types. It is suggested that it is not friction drag but rather turbulent mixing that leads to a moon horizontally uniform boundary layer and which is responsible for the different behavior of the inland breeze, i.e., a weak and nonpropagating circulation.