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Title: Precipitation chemistry in and ionic loading to an alpine basin, Sierra Nevada

Journal Article · · Water Resources Research; (United States)
DOI:https://doi.org/10.1029/90WR02773· OSTI ID:5715877
;  [1]
  1. Univ. of California, Santa Barbara (United States)

Wet deposition of solutes to an alpine catchment in the southern Sierra Nevada was measured from October 1984 through March 1988. Rainfall had a volume-weighted pH of 4.9, and snowfall had a volume-weighted pH of 5.3. Acetic and formic acids were important components of all wet deposition, contributing 25-30% of the measured anions in snowfall and, through analysis of charge balance deficits, the same percentage in rainfall. The NO{sub 3}{sup {minus}} to SO{sub 4}{sup 2{minus}} equivalent ratio for all wet deposition was 1.16. Ammonium concentration was tenfold greater than H{sup +} in rainfall: ammonium nitrate and ammonium sulfate appear to be the principal nitrate and sulfate containing aerosols in wet deposition. Snowmelt runoff (1985 and 1986) or snowpack runoff plus rainfall during the period of snowpack runoff (1987) supplied 90% of the annual solute flux from wet deposition to the catchment. Data show that dry deposition was not an important contributor of H{sup +}, NO{sub 3}{sup {minus}}, and SO{sub 4}{sup 2{minus}} to the winter snowpack. The source of the ions in snowfall was air masses that originated over the Pacific Ocean, while low Cl{sup {minus}} and Na{sup +} relative to NO{sub 3}{sup {minus}} and NH{sub 4}{sup +} in rainfall indicate that local urban and agricultural areas were the major source of the ions in rainfall.

OSTI ID:
5715877
Journal Information:
Water Resources Research; (United States), Vol. 27:7; ISSN 0043-1397
Country of Publication:
United States
Language:
English