Overview

The aerosol module SALSA (Kokkola et al., 2008) embedded in PALM can be used to simulate the aerosol particle concentrations, size distributions and chemical compositions. In SALSA, the aerosol size distribution is represented as a discrete set of size bins (by default 10 bins). The number n_i (m^-3) and mass concentration m_c,i (kg m^-3) of each size bin i and chemical component c are the model prognostic variables. Currently, the following chemical components can be included: sulphuric acid (H2SO4), organic carbon (OC), black carbon (BC), nitric acid (HNO3), ammonium (NH3), sea salt, dust and water (H2O). Furthermore, the gaseous concentrations of H2SO4, HNO3, NH3 and semi- and non-volatile organics (OCNV and OCSV) are also default prognostic variables. The aerosol dynamic processes included are coagulation, condensation of H2SO4, organics and water vapour, dissolutional growth by HNO3 and NH3, nucleation and dry deposition on horizontal and vertical surfaces and resolved vegetation.

SALSA can be coupled with the chemistry module. In that case, the five gaseous compounds (H2SO4, HNO3, NH3, OCNV and OCSV) will be imported to SALSA from the chemistry module and should thus be included in the chemical mechanism applied.

SALSA is enabled by adding the NAMELIST salsa_parameters with appropriate parameters to the INPUT parameter file (<run_identifier>_p3d). Available parameters are listed below.