Modelling internal boundary-layer development in a region with a complex coastline

The purpose of this paper is to test the ability of two quite different mod els to simulate the combined spatial and temporal variability of the intern al boundary layer in an area of complex terrain and coastline during one da y. The simple applied slab model of Gryning and Batchvarova, and the Colora do State University Regional Atmospheric Modelling System (CSU-RAMS) are te sted by comparison with data gathered during a field study (called Pacific '93) of photochemical pollution in the Lower Fraser Valley of British Colum bia, Canada. The data utilised here are drawn from tethered balloon flights , free flying balloon ascents, and downlooking lidar operated from an aircr aft flown at roughly 3500 m above sea level. Both models are found to repre sent the temporal and spatial development of the internal boundary-layer de pth over the Lower Fraser Valley very well, and reproduce many of the finer details revealed by the measurements.