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Title: A Sudden Increase in the Concentration of Dissolved Organic Carbon in Precipitation at a Northeastern US Forest
The oxidation of organic matter from fuel combustion or vegetation emissions into organic acids is a major source of dissolved organic carbon (DOC) in precipitation. Long‐term measurements of DOC in precipitation are rare, but the existing records mostly show decreases due to reduction in fuel combustion. Here, we show a recent, sudden increase in precipitation DOC concentration in a 27‐year record from the Hubbard Brook Experimental Forest (HBEF) in northern New Hampshire, USA Starting in 2010, where mean annual DOC concentration increased from about 80 to 130 μmol L−1in 2022. No other solutes in precipitation showed a similar sudden change. The weekly DOC concentration was not clearly related to the 72‐hr air mass trajectory characteristics or changes in trajectories. We assessed the feasibility of multiple possible causes for the DOC increase, including an increase in biogenic volatile organic compound (BVOC) emissions from the forest or from forest fires, changes in oxidation processes in the troposphere, and changes in gas‐phase solubility due to increasing pH in precipitation. Further study of sudden changes in BVOC emissions in the region, possible causes, and air quality effects are warranted.  more » « less
Award ID(s):
2224545
PAR ID:
10660449
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley on behalf of the American Geophysical Union (AGU)
Date Published:
Journal Name:
Journal of Geophysical Research: Atmospheres
Volume:
130
Issue:
20
ISSN:
2169-897X
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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