FACTOR-ANALYSIS OF TRENDS IN TEXAS ACIDIC DEPOSITION

Precipitation chemistry data collected between 1980 and 1987 for 11 NADP/NTN sites in Texas have been analyzed using factor analysis and a trend analysis of monthly averages. Factor analysis identified four major factors which differed significantly from site to site: (1) a Gulf factor of Na+, Cl-, and Mg2+; (a) a soil factor of Ca2+, K+, Na+, and Mg2+; (3) an acid factor of H+, NO3-, and SO42-; and (4) an aged aerosol factor of NO3-, SO42-, and NH4+. At Longview, the acid and Gulf factors accounted for 18 and 46%, respectively, of the variation of the data. A trend analysis was performed on the logarithm of the monthly averages at the Longview and Victoria sites, the two sites with the largest and most complete data. Results suggest that hydrogen ions have been increasing at both sites, while calcium ions have been decreasing.