RAINS-Asia: Atmospheric Transport and Deposition

The estimation of deposition loads in RAINS-Asia's atmospheric source/receptor relationships, calculated using an atmospheric transport/deposition model, in this case, the National Oceanic and Atmospheric Administration's (NOAA) Branching Atmospheric Trajectory (BAT) model. The model can be run for an entire year for each identified source, calculating the total annual deposition attributable to that source. Similarly, when run for all sources and areas, the model calculates the total annual deposition over the entire model region. The DEP module uses input data on emissions and source locations from the ENEM module, comprising both anthropogenic and natural sources, including:

large point sources (LPS's)
area emissions (subdivided by industrial, domestic, and transportation categories)
shipping activities (including regional shipping lanes and in-port activities)
active volcanoes.

Thus DEP can be used to answer questions such as:

How do changes in energy consumption and emissions from a specific area, or a single large point source, affect levels of acid deposition in other areas?
What sources or areas contribute to sulfur deposition in a given region?

RAINS-Asia: Sulfur deposition, 1990

The model uses meteorological data of the U.S. National Oceanic and Atmospheric Administration for approximately 200 stations in the region, and precipitation data from the National Center for Atmospheric Research, as well as monitoring sites in the region. The model provides annual average (wet + dry) sulfur deposition values and monthly average SO₂ concentration values for each 1° × 1° grid cell. Concentration and deposition values are calculated separately for large point sources and area sources. For dispersed area sources, the results are aggregated, showing each region's contribution to deposition in a particular grid cell. Emissions from each large point source (LPS) are calculated individually, showing the contribution of each LPS to each grid cell.

Since most existing SO₂ monitoring stations in the region are based in urban areas, it was necessary to gather more base-level data for further model evaluation. A notable result from Phase I of this project has been the initiation of a network of inexpensive sulfur dioxide air samplers at 43 sites in 11 countries to obtain more broad-based monitoring data for the model.

The model was developed at the Center for Global and Regional Environmental Research, University of Iowa. A Focal Center for the RAINS-Asia atmospheric transport and deposition studies was established at the Center for Atmospheric Sciences, Indian Institute of Technology (IIT) in Delhi. This focal center serves as the principal hub of communication and activities related to the development and use of the Asian model.

For further information on deposition estimates and the Asian model, contact University of Iowa.

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International Institute for Applied Systems Analysis