The Performance of Different Boundary-Layer Parameterisations in Meteorological Modelling in a Southwestern Coastal Area of the Iberian Peninsula

Abstract

The performance of four atmospheric boundary layer (ABL) schemes in reproducing the diurnal cycles of surface meteorological parameters as well as the ABL structure and depth over a coastal area of southwestern Iberia was assessed using the mesoscale meteorological Weather Research and Forecasting (WRF) model. The standard configuration of the medium-range forecast (MRF) and the Yonsei University (YSU) ABL schemes were employed. Modified versions of each, in which the values of the bulk critical Richardson number (Rib cr ) and the coefficient of proportionality (b) were varied, were also used. The results were compared to meteorological measurements representative of SW-NW and NE synoptic flows. The WRF model in its basic configuration was found to yield satisfactory forecasting results for nearly all near-surface atmospheric variables. Modifications in Rib cr and b did not influence the simulation of surface meteorological parameters. Both parameterisations appeared to be optimal predictors of ABL structure, and all four ABL schemes tended to produce a cold ABL during both periods, although this ABL was drier in the SW-NW flow season and wetter in the NE flow season. Considering all the parameters analysed, the MRF ABL parameterisation with the lowest values of Rib cr and b coefficients tested (0.25 and 0.0, resp.) tends to show a realistic simulation.