THE SPATIAL VARIABILITY OF RAINFALL pH IN THE WASHINGTON, D.C METROPOLITAN AREA ∗

∗We thank the volunteer observers: S. Adams, C. E. Arens, E. W. Bennington, C. Bubb, O. Byrd, E. M. Callicott, V. Castello, V. Clayton, P. H. Dernoden, J. Ernst, W. Grimes, P. Groves, R. A. Harper, S. Heidel, R. Holden, F. Kniskern, C. Lambert, R. Leffler, J. M. Mitchell, R. Mitchell, D. R. Monro, Jr., J. Pearl, D. Sammons, S. W. Sawyer, T. Tellerico, D. Thompson, J. A. Wagner and B. Young; and the U.S. Weather Service's Synoptic Forecasting Branch in Camp Springs, MD. A grant from the General Research Board of the University of Maryland provided new rain gauges and laboratory supplies. We also acknowledge the advice of two anonymous reviewers and R. Mitchell's editorial suggestions.

Abstract

This study evaluated the pH of rain water at 28 sample stations throughout the Washington, D.C. metropolitan area and determined the efficacy of utilizing a volunteer sampling network under a limited budget. Twelve rain events from September 1984 to August 1985 were analyzed. Despite the small number of events sampled, a strong relationship emerged between storm path, pH pattern, and average rainfall pH. A long, overland storm track yielded low rainfall pH and a simple spatial pattern of rain pH, while coastal storms produced relatively higher pH and a pattern with many areas of local variability.

Key Words:

• acid rain
• spatial pattern
• storm paths
• Washington
• D.C.
• pollution

Notes

∗We thank the volunteer observers: S. Adams, C. E. Arens, E. W. Bennington, C. Bubb, O. Byrd, E. M. Callicott, V. Castello, V. Clayton, P. H. Dernoden, J. Ernst, W. Grimes, P. Groves, R. A. Harper, S. Heidel, R. Holden, F. Kniskern, C. Lambert, R. Leffler, J. M. Mitchell, R. Mitchell, D. R. Monro, Jr., J. Pearl, D. Sammons, S. W. Sawyer, T. Tellerico, D. Thompson, J. A. Wagner and B. Young; and the U.S. Weather Service's Synoptic Forecasting Branch in Camp Springs, MD. A grant from the General Research Board of the University of Maryland provided new rain gauges and laboratory supplies. We also acknowledge the advice of two anonymous reviewers and R. Mitchell's editorial suggestions.