The Sea-Breeze Front Analytical Model

Abstract

Analytical solutions to the nonlinear equations of motion are used to describe the sea breeze front. It is found that the front can develop when the atmosphere stratification in the heated layer is neutral or unstable. The temperature drop due to front passage is proportional to the square of the difference between the front speed and the synoptic wind. This square of the difference, on the other hand, is proportional to [2?(s?)/?m]ga where ?(s?) is the mean potential temperature drop across the front and a is the front radius. Fronts which have the same speed of propagation and size, have a larger temperature drop when the synoptic wind blows in the opposite direction to the direction of propagation. Onshore winds associated with strong convergence are obtained in the lower part of the front, while the return current associated with strong divergence is observed in the upper part. The vertical velocity reaches values of some meters per second in the front region. The front propagation is studied in terms of the vorticity equation. The buoyancy term always tends to propagate the front inland. The nonlinear advective term in most of the cases tends to slow this propagation. In some of the cases when buoyancy is very low the advective term tends to propagate the front inland.