A secondary organic aerosol scheme in 10 reactions: the no frills approach to global aerosol modelling
Dr Kathryn Emmerson, School of Earth and Environment, University of Leeds
Tuesday 14 September 2010, 1100-1200
LEC Training Rooms 1 And 2
Atmospheric Science Seminar
Box modellers produce large chemical mechanisms to describe the atmosphere explicitly. Whilst large schemes are useful for representing the detail of the chemistry their computational expense means they cannot be used to simulate the global scale.
We have designed a secondary organic aerosol (SOA) scheme which describes the production of 1 generic lumped anthropogenic, and 1 generic lumped biogenic condensable product in just 10 reactions. It is derived from simulations of the highly explicit Master Chemical Mechanism (~13500 reactions) and its smaller relative, the
CRIv2-R5 (~550 reactions) which fill chemical composition space. A parameterisation of the key processes producing our chemical species is optimized within this chemical composition space. Under the range of conditions simulated (from clean to very polluted), we find our parameterized SOA scheme sits within 20% of the two larger scheme's results.
We have incorporated our SOA scheme into TOMCAT/GLOMAP, our global aerosol microphysics and chemical transport model. We present global fields of anthropogenic and biogenic SOA from this study, which compare favourably with current global estimates for SOA burdens.