TY  - JOUR
A1  - Bourtsoukidis, Efstratios
A1  - Bonn, Boris
A1  - Dittmann, Anna
A1  - Hakola, Hannele
A1  - Hellén, Heidi
A1  - Jacobi, Stefan
T1  - Ozone stress as a driving force of sesquiterpene emissions: a suggested parameterization [Discussion paper]
T2  - Biogeosciences discussions
N2  - Sesquiterpenes (C15H24) are semi-volatile organic compounds emitted by vegetation and are of interest in atmospheric research because they influence the oxidative capacity of the atmosphere and contribute to the formation of secondary organic aerosols. However, little is known about their emission pattern and no established parameterization is available for global emission models. The aim of this study is to investigate a Central European spruce forest and its emission response to meteorological and environmental parameters, looking for a parameterization that incorporates heat and oxidative stress as the main driving forces of the induced emissions. Therefore, a healthy ca. 80 yr old Norway spruce (Picea abies) tree was selected and a dynamical vegetation enclosure technique was applied from April to November 2011. The emissions clearly responded to temperature changes with small variations in the β-factor along the year (βspring=0.09 ± 0.01, βsummer=0.12 ± 0.02, βautumn=0.11 ± 0.02). However, daily calculated values revealed a vast amount of variability in temperature dependencies ((0.02 ± 0.002)< β<(0.27 ± 0.04)) with no distinct seasonality.
By separating the complete dataset in 10 different ozone regimes, we found that in moderately or less polluted atmospheric conditions the main driving force of sesquiterpene emissions is the temperature, but when ambient ozone mixing ratios exceed a~critical threshold of (36.6 ± 3.9) ppbv, the emissions become primarily correlated with ozone. Considering the complete dataset, cross correlation analysis resulted in highest correlation with ambient ozone mixing ratios (CCO3=0.63 ± 0.01; CCT=0.47 ± 0.02 at t=0 h for temperature) with a time shift 2–4 h prior to the emissions. An only temperature dependent algorithm was found to substantially underestimate the induced emissions (20 % of the measured; R2=0.31). However, the addition of an ozone dependent term improved substantially the fitting between measured and modeled emissions (81 % of the measured; R2=0.63), providing confidence about the reliability of the suggested parameterization for the spruce forest site investigated.
Y1  - 2012
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/27147
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-271475
SN  - 1810-6285
N1  - © Author(s) 2012. CC Attribution 3.0 License
VL  - 9
SP  - 7661
EP  - 7700
PB  - Copernicus
CY  - Katlenburg-Lindau [u. a.]
ER  -