A technique for determining regional scale flow and precipitation patterns upwind of a receptor site

A method of analyzing spatial flow and precipitation patterns associated with long-range transport is presented. This technique uses hourly precipitation data and model-calculated mixed layer trajectories to determine these patterns upwind of a receptor site. Precipitation is determined at hourly points along trajectories in a statistical sense using estimates of error in long-range trajectory calculations. This technique is used in seasonal analyses of fine particle concentrations at a remote northern Great Plains sampling site during summer 1980. The analyses show that there are distinctly different flow and precipitation patterns during high and low fine particle concentration periods. Highest fine sulfur particle concentrations occurred when flow was from the south with a higher frequency of precipitation. Highest fine soil particle concentrations occurred when precipitation frequencies were lower.