Numerical Experiments on MMS-CMAQ Sensitivity to Various PBL Schemes

To study air quality modeling sensitivity to various planetary boundary layer (PBL) schemes implemented in MM5, the Community Multiscale Air Quality (CMAQ) modeling system developed by the United States Environmental Protection Agency (USEPA) along with the PSU/NCAR mesoscale modeling system MM5 is used. Two 37-day periods, representing typical summer and winter periods, are selected for the simulation. The MM5 domain covers the continental US while the CMAQ domain covers much of the central and eastern U.S. There are 34 vertical layers in MM5 and 18 in CMAQ. MM5 is run with five of the seven commonly used PBL schemes to generate a series of gridded meteorological fields. The sensitivity of MM5-CMAQ modeling to the various PBL schemes is assessed and quantified by comparing model output against observations from the meteorological and the air quality monitoring networks within the CMAQ domain.