A MODEL FOR THE HEIGHT OF THE INTERNAL BOUNDARY-LAYER OVER AN AREA WITH AN IRREGULAR COASTLINE

A model for the time and space variation of the internal boundary-laye r height over a land area with an irregular coastline is presented. It is based on the analytical model of the boundary-layer height propose d by Gryning and Batchvarova(1990) and Batchvarova and Gryning(1991). The model accounts for the temperature jump and the mean vertical air motion at the top of the internal boundary-layer. Four cases from expe riments in Nanticoke and Vancouver are used for model validation. The agreement between the calculated and measured internal boundary layer height at the observational sites is fairly good. The input informatio n for the model consist of wind speed and direction, friction velocity and kinematic heat flux in time and space for the area, and the poten tial temperature gradient and the mean vertical air motion above the i nternal boundary layer. For the experiments used in the validation the effect of subsidence is relatively important in the afternoon under l ow wind speed high pressure conditions, lowering the height of the int ernal boundary layer by up to 10%, and it is negligible in the morning hours. The effect of the mixing height over the sea is found to be ne gligible.