Details:

Journal Title:
Atmospheric Chemistry and Physics
Personal Author:
Su, Luping ; Patton, Edward G. ; Vilà-Guerau de Arellano, Jordi ; Guenther, Alex B. ; Kaser, Lisa ; ... More +
Su, Luping ; Patton, Edward G. ; Vilà-Guerau de Arellano, Jordi ; Guenther, Alex B. ; Kaser, Lisa ; Yuan, Bin ; Xiong, Fulizi ; Shepson, Paul B. ; Zhang, Li ; Miller, David O. ; Brune, William H. ; Baumann, Karsten ; Edgerton, Eric ; Weinheimer, Andrew ; Misztal, Pawel K. ; Park, Jeong-Hoo ; Goldstein, Allen H. ; Skog, Kate M. ; Keutsch, Frank N. ; Mak, John E. Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research) ; ESRL (Earth System Research Laboratory) ; CIRES (Cooperative Institute for Research in Environmental Sciences) ; CSL (Chemical Sciences Laboratory)
OAR (Oceanic and Atmospheric Research) ; ESRL (Earth System Research Laboratory) ; CIRES (Cooperative Institute for Research in Environmental Sciences) ; CSL (Chemical Sciences Laboratory) Less -
Description:
The emission, dispersion, and photochemistry of isoprene (C5H8) and related chemical species in the convective boundary layer (CBL) during sunlit daytime were studied over a mixed forest in the southeastern United States by combining ground-based and aircraft observations. Fluxes of isoprene and monoterpenes were quantified at the top of the forest canopy using a high-resolution proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS). Snapshot (similar to aEuro-2aEuro-min sampling duration) vertical profiles of isoprene, methyl vinyl ketone (MVK)aEuro-+aEuro-methacrolein (MACR), and monoterpenes were collected from aircraft every hour in the CBL (100-1000aEuro-m). Both ground-based and airborne collected volatile organic compound (VOC) data are used to constrain the initial conditions of a mixed-layer chemistry model (MXLCH), which is applied to examine the chemical evolution of the O-3-NOx-HOx-VOC system and how it is affected by boundary layer dynamics in the CBL. The chemical loss rate of isoprene (similar to aEuro-1aEuro-h) is similar to the turbulent mixing timescale (0.1-0.5aEuro-h), which indicates that isoprene concentrations are equally dependent on both photooxidation and boundary layer dynamics. Analysis of a model-derived concentration budget suggests that diurnal evolution of isoprene inside the CBL is mainly controlled by surface emissions and chemical loss; the diurnal evolution of O-3 is dominated by entrainment. The NO to HO2 ratio (NOaEuro-:aEuro-HO2) is used as an indicator of anthropogenic impact on the CBL chemical composition and spans a wide range (1-163). The fate of hydroxyl-substituted isoprene peroxyl radical (HOC5H8OO center dot; ISOPOO) is strongly affected by NOaEuro-:aEuro-HO2, shifting from NO-dominant to NO-HO2-balanced conditions from early morning to noontime. This chemical regime change is reflected in the diurnal evolution of isoprene hydroxynitrates (ISOPN) and isoprene hydroxy hydroperoxides (ISOPOOH).
Source:
Atmospheric Chemistry and Physics, 16(12), 7725-7741.
DOI:
https://doi.org/10.5194/acp-16-7725-2016
Document Type:
Journal Article
Rights Information:
CC BY
Compliance:
Submitted
Main Document Checksum:
[+]
urn:sha256:413cc9d035ca4b469dc7d9657f31655e4d50a9e01fa045b409d830a478227e71
Download URL:
https://repository.library.noaa.gov/view/noaa/21873/noaa_21873_DS1.pdf
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