Spatial and Temporal Variability of Precipitation and Chemistry: Case Studies from the Frontal Boundary Study

Abstract

Sequential precipitation and precipitation chemistry measurements were conducted on a 37-site, 100 km ? 100 km array in central Ohio during four cyclonic storms during the fall of 1989. Spatial (network) averages and variances in rainfall rate and inorganic chemical concentrations were calculated for hourly and total-event time periods. The average fractional intersite differences in concentrations vary among the events, and range from about 0.1 to 1, with sulfate among the least variable species. This variability is at best weakly correlated with intersite distance over the range 10?90 km. Removal of the estimated effect of rainfall rate variations on chemistry reduces interevent and intersite distance variability. In these events, there appears to be a ?baseline? subgrid-scale spatial variability (including measurement error) for sulfate of no more than about 20%.