Comparison of the WRF and SODAR Derived Planetary Boundary Layer Height

In this work we compare the Planetary Boundary Layer Height (PBLH), calculated with the Weather Research and Forecasting (WRF) model, with the measurements from an acoustic remote sounding system (SODAR) gathered at Wrocław, SW Poland. The comparison is done for 15-30 November 2011. During this period, very high concentrations of PM2.5 were observed in SW Poland. For 9 days, 24-hour average PM2.5 concentrations reached the level “unhealthy for sensitive groups” and for 2 days “unhealthy” level according to Air Quality Index.
Four simulations were run with different planetary boundary layer schemes for the innermost domain. The PBL schemes tested were: Yonsei University (sim1), Mellor-Yamada Nakanishi and Niino Level 3 (sim2), Asymmetric Convective Model 2 (sim3) and Bougeault-Lacarrère (sim4). The results show that all the schemes tested overestimate the PBLH, with the largest mean error for sim1 and sim2 (215 and 225m, respectively). The mean error is significantly smaller for sim3 and sim4 (109 and 72m, respectively). The agreement between the WRF and Sodar PBLH has diurnal pattern and changes with the Pasquill stability classes. The overestimation of the PBLH might lead to the underestimation of air pollutants concentrations modelled with the air quality models.