Sensitivity of Atmospheric Composition Mesoscale Simulations in the Mediterranean to the Meteorological Data and Chemical Boundary Conditions

Abstract

Limited area models applied at higher resolution than global models and using datasets of higher resolution are generally expected to more accurately represent the spatiotemporal variability of key meteorological and climate parameters such as near surface temperature, pressure, wind speed and atmospheric composition. However, limited area models require boundary conditions and the accuracy of such datasets reflects on the accuracy of the mesoscale simulations of atmospheric composition, in particular of the longer-lived species. The effects of various resolution meteorological data and of different chemical boundary and initial conditions on the simulated concentrations of the chemical gases and aerosols in the Mediterranean have been here investigated. Two different simulations in three domains of progressively increasing horizontal resolution were performed for the year 2016 using the mesoscale Weather Research and Forecasting (WRF) meteorological model with the chemistry module (WRF-Chem) and an additional one with different chemical boundary and initial conditions. Meteorology from the Global Forecast System (GFS) at two different horizontal resolutions (1 × 1° and 0.25 × 0.25°) available from NOAA has been used in the model to investigate their impact on the simulated air pollutants. The higher resolution meteorological input improves the comparison of model results to observations. The results are found sensitive to the chemical boundary and initial conditions.