MAXIMUM VELOCITY OF THE SEA-BREEZE IN A 2-DIMENSIONAL MODEL

The influence of horizontal grid resolution (DELTAx) and horizontal diffusion on the maximum velocity of the sea breeze circulation is discussed using the results of a two-dimensional numerical model. The computed maximum updraft (W(MAX)) of the sea breeze decreases as DELTAx increases when DELTAx is larger than a certain value. The maximum velocity, however, approaches a constant as DELTAx is decreased to values less than the value. Increasing the grid interval is similar to smoothing the peak values of the velocity. The peak values, therefore, are decreased as the grid size is increased. Further, it was found that the W(MAX) is significantly weakened by horizontal diffusion. The magnitude Of W(MAX) at a given point is not very meaningful, since the value can be altered by changing the grid size and the smoothing method. The area-weighted W(MAX) appears to be more physically significant in numerically simulated results. Therefore, use should be made of an appropriately fine grid for studying a given phenomena.