Precipitation chloride at West Point, NY: Seasonal patterns and possible contributions from non-seawater sources
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- 作者：J.B. Shapiro ; H.J. Simpson ; K.L. Griffin ; W.S.F. Schuster
- 关键词：NADP ; HCl ; Coal combustion ; Incineration ; Sea-salt dechlorination
- 刊名：Atmospheric Environment
- 出版年：2007
- 出版时间：March 2007
- 年：2007
- 卷：41
- 期：10
- 页码：2240-2254
- 全文大小：369 K
文摘
Chloride derived from the atmosphere can be a valuable tracer in ecosystem and watershed processes. For these purposes and other environmental studies, it is important to establish temporal patterns and sources for Cl- in wet deposition. Weekly composite precipitation samples have been analyzed by the National Atmospheric Deposition Program/National Trends Network (NADP/NTN) at West Point, NY during 1981–2003, although systematic contamination of precipitation Na+ significantly perturbed data for Na+ prior to 1998. Chloride and sodium ion seasonal wet deposition were highest in winter and lowest in summer through most of the record, probably as a result of more frequent marine-trajectory storms in winter. During 1998–2003, the period of highest quality Na+ data, the ratio of [Cl-]/[Na+] was significantly higher than average in summer and lower in winter. Higher summer [Cl-]/[Na+] occurred consistently throughout the record, often reaching values four times the seawater ratio. Based on the ratio of [Cl-]/[Na+] in seawater of annual wet deposition of Cl- during 1998–2003 was in excess of that for surface seawater. Additionally, a minor terrestrial dust Na+ component was approximated, which had the net effect of increasing annual excess Cl- wet deposition to 22 % ( or ) of the mean annual Cl- wet deposition at West Point ( or ). Consistent with plausible sources of non-seawater 834895c"" title=""Click to view the MathML source"">Cl-, we attribute excess Cl- wet deposition to HCl emission from coal fired generating stations, HCl emissions from domestic and industrial waste incineration and to HCl formation in the regional atmosphere from reactions of sea-salt aerosols with S and N acidic gases.