An analysis of precipitation chemistry data from Alaska

Uri Dayan*, John M. Miller, William C. Keene, James N. Galloway

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

The chemical composition of precipitation collected at Poker Flat, Alaska and at Point Barrow, Alaska was evaluated in conjunction with backward air trajectories to characterize the long-range transport of acidic materials to central Alaska. Volume weighted mean concentrations of major chemical constituents characterized the composition and acidity of precipitation associated with air parcels which arrive at Poker Flat from three major source regions, the Pacific ocean, local continental and the Arctic. Long-range trajectories from the south-west predominated during the spring and early summer. These air flow patterns originated in mid-latitudes and generated precipitation with moderate acidities (H+ = 9.9 μeq ℓ-1). Weak flows, suggesting local airmasses, were important sources of precipitation during mid summer. Local storms corresponded to higher acidities (H+ = 12.7 μeqℓ-1). During the late summer and early autumn, precipitation events were frequently associated with northerly flows and lower acidities (H+ = 7.8 μeqℓ-1). H2SO4 was the most important source of acidity contributing, on a volume weighted basis, between 46 and 80% of free H+ in all samples. The higher concentration of SO42- relative to H+ in Arctic storms suggests long distance transport and neutralization of anthropogenic H2SO4 from the Polar region. Concentrations of excess SO42- measured in precipitation from Alaska were greater than those measured in precipitation from Greenland and less than those measured in precipitation from the Yukon of Canada.

Original languageEnglish
Pages (from-to)651-657
Number of pages7
JournalAtmospheric Environment
Volume19
Issue number4
DOIs
StatePublished - 1985
Externally publishedYes

Keywords

  • air trajectories
  • long-range transport
  • Precipitation chemistry

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