Numerical Approximation of the Transport Equation: Comparison of Five Positive Definite Algorithms

IIASA's Regional Acidification INformation and Simulation (RAINS) model will be used to develop and assess international control strategies to reduce emissions of acidifying pollutants. These strategies will involve the expenditure of large sum of money; it is important, therefore, to assess the effect of uncertainties in the model on its results. An important component of the RAINS model is its atmospheric transport component; this paper reports the results of examining several algorithms for solution of the atmospheric transport equation. It also represents a joint effort between IIASA scientists and those in the Institute of Meteorology and Water Management in Warsaw and Central Institute for Meteorology and Geodynamics in Vienna.