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Title: Airborne measurements of isoprene and monoterpene emissions from southeastern U.S. forests

Abstract

Isoprene and monoterpene emission rates are essential inputs for atmospheric chemistry models that simulate atmospheric oxidant and particle distributions. Process studies of the biochemical and physiological mechanisms controlling these emissions are advancing our understanding and the accuracy of model predictions but efforts to quantify regional emissions have been limited by a lack of constraints on regional distributions of ecosystem emission capacities. We used an airborne wavelet-based eddy covariance measurement technique to characterize isoprene and monoterpene fluxes with high spatial resolution during the 2013 SAS (Southeast Atmosphere Study) in the southeastern United States. The fluxes measured by direct eddy covariance were comparable to emissions independently estimated using an indirect inverse modeling approach. Isoprene emission factors based on the aircraft wavelet flux estimates for high isoprene chemotypes (e.g., oaks) were similar to the MEGAN2.1 biogenic emission model estimates for landscapes dominated by oaks. Aircraft flux measurement estimates for landscapes with fewer isoprene emitting trees (e.g., pine plantations), were about a factor of two lower than MEGAN2.1 model estimates. The tendency for high isoprene emitters in these landscapes to occur in the shaded understory, where light dependent isoprene emissions are diminished, may explain the lower than expected emissions. This result demonstrates the importancemore » of accurately representing the vertical profile of isoprene emitting biomass in biogenic emission models. Airborne measurement-based emission factors for high monoterpene chemotypes agreed with MEGAN2.1 in landscapes dominated by pine (high monoterpene chemotype) trees but were more than a factor of three higher than model estimates for landscapes dominated by oak (relatively low monoterpene emitting) trees. This results suggests that unaccounted processes, such as floral emissions or light dependent monoterpene emissions, or vegetation other than high monoterpene emitting trees may be an important source of monoterpene emissions in those landscapes and should be identified and included in biogenic emission models.« less

Authors:
ORCiD logo; ORCiD logo; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1406787
Report Number(s):
PNNL-SA-128489
Journal ID: ISSN 0048-9697
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Science of the Total Environment
Additional Journal Information:
Journal Volume: 595; Journal Issue: C; Journal ID: ISSN 0048-9697
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; airborne; isoprene; monoterpene; emissions

Citation Formats

Yu, Haofei, Guenther, Alex, Gu, Dasa, Warneke, Carsten, Geron, Chris, Goldstein, Allen, Graus, Martin, Karl, Thomas, Kaser, Lisa, Misztal, Pawel, and Yuan, Bin. Airborne measurements of isoprene and monoterpene emissions from southeastern U.S. forests. United States: N. p., 2017. Web. doi:10.1016/j.scitotenv.2017.03.262.
Yu, Haofei, Guenther, Alex, Gu, Dasa, Warneke, Carsten, Geron, Chris, Goldstein, Allen, Graus, Martin, Karl, Thomas, Kaser, Lisa, Misztal, Pawel, & Yuan, Bin. Airborne measurements of isoprene and monoterpene emissions from southeastern U.S. forests. United States. doi:10.1016/j.scitotenv.2017.03.262.
Yu, Haofei, Guenther, Alex, Gu, Dasa, Warneke, Carsten, Geron, Chris, Goldstein, Allen, Graus, Martin, Karl, Thomas, Kaser, Lisa, Misztal, Pawel, and Yuan, Bin. Sun . "Airborne measurements of isoprene and monoterpene emissions from southeastern U.S. forests". United States. doi:10.1016/j.scitotenv.2017.03.262.
@article{osti_1406787,
title = {Airborne measurements of isoprene and monoterpene emissions from southeastern U.S. forests},
author = {Yu, Haofei and Guenther, Alex and Gu, Dasa and Warneke, Carsten and Geron, Chris and Goldstein, Allen and Graus, Martin and Karl, Thomas and Kaser, Lisa and Misztal, Pawel and Yuan, Bin},
abstractNote = {Isoprene and monoterpene emission rates are essential inputs for atmospheric chemistry models that simulate atmospheric oxidant and particle distributions. Process studies of the biochemical and physiological mechanisms controlling these emissions are advancing our understanding and the accuracy of model predictions but efforts to quantify regional emissions have been limited by a lack of constraints on regional distributions of ecosystem emission capacities. We used an airborne wavelet-based eddy covariance measurement technique to characterize isoprene and monoterpene fluxes with high spatial resolution during the 2013 SAS (Southeast Atmosphere Study) in the southeastern United States. The fluxes measured by direct eddy covariance were comparable to emissions independently estimated using an indirect inverse modeling approach. Isoprene emission factors based on the aircraft wavelet flux estimates for high isoprene chemotypes (e.g., oaks) were similar to the MEGAN2.1 biogenic emission model estimates for landscapes dominated by oaks. Aircraft flux measurement estimates for landscapes with fewer isoprene emitting trees (e.g., pine plantations), were about a factor of two lower than MEGAN2.1 model estimates. The tendency for high isoprene emitters in these landscapes to occur in the shaded understory, where light dependent isoprene emissions are diminished, may explain the lower than expected emissions. This result demonstrates the importance of accurately representing the vertical profile of isoprene emitting biomass in biogenic emission models. Airborne measurement-based emission factors for high monoterpene chemotypes agreed with MEGAN2.1 in landscapes dominated by pine (high monoterpene chemotype) trees but were more than a factor of three higher than model estimates for landscapes dominated by oak (relatively low monoterpene emitting) trees. This results suggests that unaccounted processes, such as floral emissions or light dependent monoterpene emissions, or vegetation other than high monoterpene emitting trees may be an important source of monoterpene emissions in those landscapes and should be identified and included in biogenic emission models.},
doi = {10.1016/j.scitotenv.2017.03.262},
journal = {Science of the Total Environment},
issn = {0048-9697},
number = C,
volume = 595,
place = {United States},
year = {2017},
month = {10}
}