Variability of dissolved organic carbon in precipitation during storms at the Shale Hills Critical Zone Observatory

Hydrological Processes
By: , and 

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Abstract

Organic compounds are removed from the atmosphere and deposited to the earth's surface via precipitation. In this study, we quantified variations of dissolved organic carbon (DOC) in precipitation during storm events at the Shale Hills Critical Zone Observatory, a forested watershed in central Pennsylvania (USA). Precipitation samples were collected consecutively throughout the storm during 13 events, which spanned a range of seasons and synoptic meteorological conditions, including a hurricane. Further, we explored factors that affect the temporal variability by considering relationships of DOC in precipitation with atmospheric and storm characteristics. Concentrations and chemical composition of DOC changed considerably during storms, with the magnitude of change within individual events being comparable or higher than the range of variation in average event composition among events. While some previous studies observed that concentrations of other elements in precipitation typically decrease over the course of individual storm events, results of this study show that DOC concentrations in precipitation are highly variable. During most storm events concentrations decreased over time, possibly as a result of washing out of the below-cloud atmosphere. However, increasing concentrations that were observed in the later stages of some storm events highlight that DOC removal with precipitation is not merely a dilution response. Increases in DOC during events could result from advection of air masses, local emissions during breaks in precipitation, or chemical transformations in the atmosphere that enhance solubility of organic carbon compounds. This work advances understanding of processes occurring during storms that are relevant to studies of atmospheric chemistry, carbon cycling, and ecosystem responses.

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Publication type Article
Publication Subtype Journal Article
Title Variability of dissolved organic carbon in precipitation during storms at the Shale Hills Critical Zone Observatory
Series title Hydrological Processes
DOI 10.1002/hyp.11235
Volume 31
Issue 16
Year Published 2017
Language English
Publisher Wiley
Contributing office(s) Utah Water Science Center
Description 16 p.
First page 2935
Last page 2950
Country United States
State Pennsylvania
Other Geospatial Stone Valley Forest
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