Environmental Engineering Reference
In-Depth Information
2.31 Forecasting Sulphur and Nitrogen Oxides, Ozone
and Aerosols as Key Components of Chemical Weather
J. Soares, M. Sofiev, M. Prank, and J. Kukkonen
Finnish Meteorological Institute, FI-00101 Helsinki, Finland
Abstract
Tropospheric aerosols and ozone are the key pollutants of the greatest
concern for the public health. This paper presents the chemical modules in deve-
lopment in SILAM and to-date verification against observed concentrations in
Europe and global remote-sensing optical information. The comparisons show that
SILAM reproduces relatively well the concentrations of the main precursors for
ozone production, and the concentration patterns of sea salt aerosol.
Keywords
Modeling, SILAM, photochemistry, sea salt aerosol
1. Introduction
The focus on the short-term forecasting of the atmospheric chemical composition
has posed several specific requirements to existing and developing chemical trans-
port models. The goal of the current study is to describe the modules currently in
development in SILAM: the photochemical and the sea salt emission module. We
also discuss the model applications at regional and global scales and compare the
model results with in situ measurements and global remote-sensing optical
information for the years 2000 and 2001.
2. Methodology
2.1. Modelling tool and input data
The modelling tool used in this study is the Air Quality and Emergency Modelling
System, SILAM (Sofiev et al., 2008a). SILAM incorporates a both Lagrangian
and Eulerian advection-diffusion formulations. The Eulerian scheme (Galperin,
1999, 2000) combines horizontal diffusion with the advection module (the scheme
itself has zero numerical viscosity) while the vertical exchange follows the
extended resistance analogy scheme of Sofiev (2002). A physico-chemical module of
SILAM includes basic SOx-NOx-NHx-VOC-O3 chemistry, a linearized scheme
