Observed and modeled ecosystem isoprene fluxes from an oak-dominated temperate forest and the influence of drought stress

Potosnak, Mark J.; LeStourgeon, L.; Pallardy, Stephen G.; Hosman, Kevin P.; Gu, Lianhong; Karl, T.; Geron, Chris; Guenther, Alex

doi:10.1016/j.atmosenv.2013.11.055

Cited by 77 publications

(170 citation statements)

References 53 publications

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“…Since the SW availability modulation (1 to 0) used in MEGAN was based on the single observation made by Pegoraro et al (2004) between Populus deltoids photosynthesis and stomatal conductance to water vapour, it is obviously not appropriate for water stress-resistant species. Such a 10 discrepancy under conditions other than Mediterranean was also noticed by Potosnak et al, 2014) during a seasonal study over a mixed broad-leaf forest mainly composed of Q. alba L.…”

Section: Towards What Isoprene Emission Modeling Improvement?mentioning

confidence: 85%

Simulating precipitation decline under a Mediterranean deciduous Oak forest: effects on isoprene seasonal emissions and predictions under climatic scenarios

Genard-Zielinski

Boissard

Ormeño

et al. 2017

Preprint

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Abstract. Seasonal variations of Q. pubescens physiology and isoprene emission rates (ER)were studied from June 2012 to June 2013 at the O 3 HP site (French Mediterranean) under natural (ND) and amplified (+30%, AD) drought. While AD significantly reduced the stomatal conductance to water vapour over the season excepting August, it did not significantly limit CO 2 net assimilation, which was the lowest in summer. ER followed a 20 significant seasonal pattern, whatever the drought intensity, with mean ER maxima of 78.5 and 104.8 µgC g DM -1 h -1 in July (ND) and August (AD) respectively. Isoprene emission factor increased significantly by a factor of 2 in August and September under AD (137.8 and 74.3 µgC g DM -1 h -1 ) compared to ND (75.3 and 40.21 µgC g DM -1 h -1 ), but no changes occurred onER. An isoprene algorithm (G14) was developed using an optimised artificial neural network 25 trained on our experimental dataset (ER + O 3 HP climatic and edaphic parameters cumulated over 0 to 21 days before measurements). G14 assessed more than 80% of the observed ER seasonal variations, whatever the drought intensity. In contrast, ER was poorly assessed under water stress by MEGAN empirical isoprene model, in particular under AD. Soil water (SW) content was the dominant parameter to account for the observed ER variations, regardless the 30 water stress treatment. ER was more sensitive to higher frequency environmental changes under AD (0 to -7 days) compared to ND (7 days). Using IPCC RCP2.6 and RCP8.5 climate scenarios, SW and temperature calculated by the ORCHIDEE land surface model, and G14, an annual 3 fold ER relative increase was found between present (2000-2010) and future (2090-2100) for RCP8.5 scenario compared to a 70% increase for RCP2.6. Future ER 35Biogeosciences Discuss.,

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Section: Towards What Isoprene Emission Modeling Improvement?mentioning

confidence: 85%

Simulating precipitation decline under a Mediterranean deciduous Oak forest: effects on isoprene seasonal emissions and predictions under climatic scenarios

Genard-Zielinski

Boissard

Ormeño

et al. 2017

Preprint

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“…The response of isoprene emissions to VPD is studied much less and not included in current biogenic emission algorithms. Isoprene emissions decrease drastically under severe drought conditions when soil moisture is below a threshold (21,32), confounding the relationship between isoprene emissions and VPD in field observations (20,21,36,37). However, a few studies reported that the current biogenic emission algorithm underestimates the enhanced isoprene emissions at the initial stage of a drought when large variation in ambient humidity occurred but the decrease in soil moisture was insignificant (20,21).…”

Section: Resultsmentioning

confidence: 99%

“…2B). Enhanced isoprene emissions are likely due in part to increased leaf temperature and decreased internal CO 2 concentration, caused by reduced stomatal conductance under mild drought stress (20). More field and laboratory measurements are obviously required to quantify the response function of isoprene emission to short-term stress of high VPD and to understand the underlying mechanisms.…”

Section: Resultsmentioning

confidence: 99%

Climate-driven ground-level ozone extreme in the fall over the Southeast United States

Zhang

Wang

2016

Proc. Natl. Acad. Sci. U.S.A.

108

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Ground-level ozone is adverse to human and vegetation health. High ground-level ozone concentrations usually occur over the United States in the summer, often referred to as the ozone season. However, observed monthly mean ozone concentrations in the southeastern United States were higher in October than July in 2010. The October ozone average in 2010 reached that of July in the past three decades . Our analysis shows that this extreme October ozone in 2010 over the Southeast is due in part to a dry and warm weather condition, which enhances photochemical production, air stagnation, and fire emissions. Observational evidence and modeling analysis also indicate that another significant contributor is enhanced emissions of biogenic isoprene, a major ozone precursor, from water-stressed plants under a dry and warm condition. The latter finding is corroborated by recent laboratory and field studies. This climate-induced biogenic control also explains the puzzling fact that the two extremes of high October ozone both occurred in the 2000s when anthropogenic emissions were lower than the 1980s and 1990s, in contrast to the observed decreasing trend of July ozone in the region. The occurrences of a drying and warming fall, projected by climate models, will likely lead to more active photochemistry, enhanced biogenic isoprene and fire emissions, an extension of the ozone season from summer to fall, and an increase of secondary organic aerosols in the Southeast, posing challenges to regional air quality management.ground-level ozone | ozone season | regional climate change | isoprene | air quality G round-level ozone is a pollutant harmful to human and vegetation health (1, 2). High ground-level ozone events are typically found in the summer when the formation of ozone is active through photochemical reactions involving nitrogen oxides (NO x = NO + NO 2 ) and volatile organic compounds (VOCs). However, ozone concentrations are sensitive to weather and climate (3-8), and the high-ozone season could extend beyond summer in the future (9-13). Previous climate-chemistry model studies have estimated the change of ground-level ozone (ΔO 3 ) in the United States resulting only from meteorological changes. Their results show large variation in the sign and magnitude of ΔO 3 in the fall, especially over forested regions such as the southeastern United States (SE) (10, 13). The lack of consensus reflects the uncertainties in modeling regional climate change and the consequent response of ground-level ozone.In this study, we focus on analyzing the historical ozone records. Fig. 1A Fig. S1). The number increases to 324 exceedances at 112 stations if the new US ambient ozone standard threshold value, 70 ppbv, is used (SI Appendix, Fig. S1). The regional average reached 65 ppbv during October 8-10, 2010 ( Fig. 2A). ppbv, considerably lower than that in the summer ozone season (∼50 ppbv in July). However, in the two extreme years, 2000 and 2010, regional monthly mean [O 3 ] MDA8 are 52 and 49 ppbv, respectively, two interannual standa...

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“…In their study the most emitted compounds were isoprene, methanol, acetone and methyl vinyl ketone + methacrolein. The high emissions can be explained by the ecosystem, as oaks are known to be strong isoprene emitters (e.g., Potosnak et al, 2014). Kaser et al (2013a) reported 8 h daytime fluxes only, so a direct comparison with the 24 h net flux from the other studies is not possible.…”

Section: Ec Voc Fluxes Above Different Ecosystemsmentioning

confidence: 99%

Temporal variation of VOC fluxes measured with PTR-TOF above a boreal forest

et al. 2018

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Abstract. Between April and June 2013 fluxes of volatile organic compounds (VOCs) were measured in a Scots pine and Norway spruce forest using the eddy covariance (EC) method with a proton transfer reaction time-of-flight (PTR-TOF) mass spectrometer. The observations were performed above a boreal forest at the SMEAR II site in southern Finland.We found a total of 25 different compounds with exchange and investigated their seasonal variations from spring to summer. The majority of the net VOC flux was comprised of methanol, monoterpenes, acetone and butene + butanol. The butene + butanol emissions were concluded to not originate from the forest and, therefore, be anthropogenic. The VOC exchange followed a seasonal trend and the emissions increased from spring to summer. Only three compounds were emitted during the snowmelt while in summer emissions of some 19 VOCs were observed. During the measurement period in April, the emissions were dominated by butene + butanol, while during the start of the growing season and in summer, methanol was the most emitted compound. The main source of methanol was likely the growth of new biomass. During a 21-day period in June, the net VOC flux was 2.1 nmol m −2 s −1 . This is on the lower end of PTR-TOF flux measurements from other ecosystems, which range from 2 to 10 nmol m −2 s −1 . The EC flux results were compared with surface layer profile measurements, using a proton transfer reaction quadrupole mass spectrometer, which is permanently installed at the SMEAR II site. For the major compounds, the fluxes measured with the two different methods agreed well.

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Observed and modeled ecosystem isoprene fluxes from an oak-dominated temperate forest and the influence of drought stress

Cited by 77 publications

References 53 publications

Simulating precipitation decline under a Mediterranean deciduous Oak forest: effects on isoprene seasonal emissions and predictions under climatic scenarios

Simulating precipitation decline under a Mediterranean deciduous Oak forest: effects on isoprene seasonal emissions and predictions under climatic scenarios

Climate-driven ground-level ozone extreme in the fall over the Southeast United States

Temporal variation of VOC fluxes measured with PTR-TOF above a boreal forest

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