TA6 Atmospheric Transport and Fate
202 Oregon Ballroom
8:00 AM - 12:00 PM, Tuesday
() Coupling Global Contaminant Mass Balance and Climate Models: The BETR Gridded Global Model.
MacLeod, M1, Riley, W1, McKone, T1, 2, 1 Lawrence Berkeley National Laboratory, Berkeley, CA, USA2 University of California, Berkeley, CA, USA
ABSTRACT- Persistent organic pollutants (POPs) are chemicals that are resistant to degradation in the environment and may cycle between environmental media such as air, water, soil and vegetation. Much of our conceptual understanding of the long-term fate and transport of POPs in the environment relies on simple models reconciled with limited observational data. The most well established contaminant fate models for POPs have evolved from multimedia mass balance models that represent the environment as a set of compartments such as air, water, soil and possibly a variety of other media. A second category of global contaminant fate models based on general circulation models (GCMs) for the atmosphere and oceans is becoming more prominent for describing the fate of POPs. GCMs simulate climate and fluid flow using fundamental equations describing the conservation of mass, energy and momentum in connected grid boxes of atmosphere or ocean water. They are typically highly spatially resolved in three dimensions, and may be calibrated to fit detailed air and water flow patterns. The purpose of this paper is to introduce a global contaminant fate model that provides more spatial and temporal detail than existing multimedia fate models by directly incorporating GCM data, but retains the transparency and multimedia structure of mass balance models. This model, the Berkeley-Trent Gridded Global Model (BETR-Global) consists of 288 linked multimedia regions coupled to monthly averaged climate data from an atmospheric GCM. We illustrate the model by application to describe the global fate and transport of selected PCB congeners over their 70-year use history, and discuss application of the model to assess the impact of climate variability on the transport of POPs.
Key words: global model, POPs, atmospheric transport, PCBs