Disjunct eddy covariance technique for trace gas flux measurements

Rinne, Janne; Guenther, Alex; Warneke, C.; Gouw, J. A. de; Luxembourg, S.L.

doi:10.1029/2001gl012900

Cited by 98 publications

(92 citation statements)

References 13 publications

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“…Calculation of BEF at canopy level has become possible thanks to flux measurements by micrometeorological techniques. 12,15,19 Canopy BEF is preferentially used to parametrize emission models, because it does not require upscaling from leaf to canopy. 29 Most trees and shrubs of the mixed Mediterranean forest were shown to be minor isoprene emitters from gas exchange studies at the leaf level.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Observations of Diurnal to Weekly Variations of Monoterpene-Dominated Fluxes of Volatile Organic Compounds from Mediterranean Forests: Implications for Regional Modeling

Fares

Schnitzhofer

Jiang

et al. 2013

Environ. Sci. Technol.

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The Estate of Castelporziano (Rome, Italy) hosts many ecosystems representative of Mediterranean vegetation, especially holm oak and pine forests and dune vegetation. In this work, basal emission factors (BEFs) of biogenic volatile organic compounds (BVOCs) obtained by Eddy Covariance in a field campaign using a proton transfer reaction−time-of-flight−mass spectrometer (PTR-TOF-MS) were compared to BEFs reported in previous studies that could not measure fluxes in real-time. Globally, broadleaf forests are dominated by isoprene emissions, but these Mediterranean ecosystems are dominated by strong monoterpene emitters, as shown by the new BEFs. The original and new BEFs were used to parametrize the model of emissions of gases and aerosols from nature (MEGAN v2.1), and model outputs were compared with measured fluxes. Results showed good agreement between modeled and measured fluxes when a model was used to predict radiative transfer and energy balance across the canopy. We then evaluated whether changes in BVOC emissions can affect the chemistry of the atmosphere and climate at a regional level. MEGAN was run together with the land surface model (community land model, CLM v4.0) of the community earth system model (CESM v1.0). Results highlighted that tropospheric ozone concentration and air temperature predicted from the model are sensitive to the magnitude of BVOC emissions, thus demonstrating the importance of adopting the proper BEF values for model parametrization.

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Section: ■ Materials and Methodsmentioning

confidence: 99%

Observations of Diurnal to Weekly Variations of Monoterpene-Dominated Fluxes of Volatile Organic Compounds from Mediterranean Forests: Implications for Regional Modeling

Fares

Schnitzhofer

Jiang

et al. 2013

Environ. Sci. Technol.

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“…The technique used to measure ecosystem BVOC fluxes is disjunct eddy-covariance by mass scanning (Karl et al, 2002;Rinne et al, 2001). The flux (F VOC ) is determined by the covariance of the discrete function between the time series of vertical wind velocity w(t) and VOC concentration C VOC (t) over an averaging period of 30 min (T ):…”

Section: Disjunct Eddy-covariancementioning

confidence: 99%

“…These studies usually cover only a small part of the vegetation season, centred on time periods when biogenic emissions are thought to be important, and are still too limited in terms of the variety of ecosystems that are potential methanol emitters. Among these techniques, disjunct eddy-covariance is the most suitable for long-term monitoring of the ecosystem exchange in real-undisturbed conditions (Rinne et al, 2001). It has been used in several methanol studies (Bamberger et al, 2010;Brunner et al, 2007;Custer and Schade, 2007;Holst et al, 2010;Karl et al, 2001Karl et al, , 2002Karl et al, , 2003Karl et al, , 2004Karl et al, , 2005Langford et al, 2010;Spirig et al, 2005), but none of them (at the exception of Hörtnagl et al, 2011 above a temperate mountain grassland) proposed a year-round follow-up of the exchange.…”

Section: Introductionmentioning

confidence: 99%

Abiotic and biotic control of methanol exchanges in a temperate mixed forest

et al. 2012

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Abstract.Methanol exchanges over a mixed temperate forest in the Belgian Ardennes were measured for more than one vegetation season using disjunct eddy-covariance by a mass scanning technique and Proton Transfer Reaction Mass Spectrometry (PTR-MS). Half-hourly methanol fluxes were measured in the range of −0.6 µg m −2 s −1 to 0.6 µg m −2 s −1 , and net daily methanol fluxes were generally negative in summer and autumn and positive in spring. On average, the negative fluxes dominated (i.e. the site behaved as a net sink), in contrast to what had been found in previous studies.An original model describing the adsorption/desorption of methanol in water films present in the forest ecosystem and the methanol degradation process was developed. Its calibration, based on field measurements, predicted a mean methanol degradation rate of −0.0074 µg m −2 s −1 and a half lifetime for methanol in water films of 57.4 h. Biogenic emissions dominated the exchange only in spring, with a standard emission factor of 0.76 µg m −2 s −1 .The great ability of the model to reproduce the long-term evolution, as well as the diurnal variation of the fluxes, suggests that the adsorption/desorption and degradation processes play an important role in the global methanol budget. This result underlines the need to conduct long-term measurements in order to accurately capture these processes and to better estimate methanol fluxes at the ecosystem scale.

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“…where w and c are the instantaneous deviations from the mean values of w and c of the sub-sample (Rinne et al, 2001;Karl et al, 2002;Grabmer et al, 2004). Compared to standard EC techniques, this leads to significantly fewer data samples (typically ∼20% of a continuously recorded data set) depending on the number of different BVOCs sampled in a measurement sequence.…”

Section: Disjunct Eddy Covariance Technique (Dec)mentioning

confidence: 99%

“…Kesselmeier and Staudt, 1999;Seco et al, 2007), but the data are mostly restricted to relatively short-term campaigns using leaf or branch cuvette techniques. A number of studies have investigated the canopy-atmosphere exchange of BVOC using the concentration gradient method, relaxed eddy accumulation (REA) methods, as well as disjunct eddy covariance techniques (DEC, Gallagher et al, 2000;Rinne et al, 2000Rinne et al, , 2001Schade and Goldstein, 2001) and, in the case of isoprene, direct eddy covariance with fast response sensors Pressley et al, 2005). Recently, the development of the proton transfer mass spectrometer (Lindinger et al, 1998;de Gouw et al, 2003;de Gouw and Warneke, 2007), in conjunction with disjunct eddy covariance techniques has led to an increased availability of flux data from a wider range of ecosystems including tropical and mid-latitude forests, grassland and crops (e.g.…”

Section: Introductionmentioning

confidence: 99%

BVOC ecosystem flux measurements at a high latitude wetland site

et al. 2010

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Abstract. In this study, we present summertime concentrations and fluxes of biogenic volatile organic compounds (BVOCs) measured at a sub-arctic wetland in northern Sweden using a disjunct eddy-covariance (DEC) technique based on a proton transfer reaction mass spectrometer (PTR-MS). The vegetation at the site was dominated by Sphagnum, Carex and Eriophorum spp. The measurements reported here cover a period of 50 days (1 August to 19 September 2006), approximately one half of the growing season at the site, and allowed to investigate the effect of day-to-day variation in weather as well as of vegetation senescence on daily BVOC fluxes, and on their temperature and light responses. The sensitivity drift of the DEC system was assessed by comparing H 3 O + -ion cluster formed with water molecules (H 3 O + (H 2 O) at m37) with water vapour concentration measurements made using an adjacent humidity sensor, and the applicability of the DEC method was analysed by a comparison of sensible heat fluxes for high frequency and DEC data obtained from the sonic anemometer. These analyses showed no significant PTR-MS sensor drift over a period of several weeks and only a small flux-loss due to high-frequency spectrum omissions. This loss was within the range expected from other studies and the theoretical considerations.Standardised (20 • C and 1000 µmol m −2 s −1 PAR) summer isoprene emission rates found in this study of 329 µg C m −2 (ground area) h −1 were comparable with findings from more southern boreal forests, and fen-like ecosystems. On a diel scale, measured fluxes indicated a stronger temperature dependence than emissions from temperate or (sub)tropical ecosystems. For the first time, to our knowledge, we report ecosystem methanol fluxes from a sub-arctic Correspondence to: T. Holst (thomas.holst@nateko.lu.se) ecosystem. Maximum daytime emission fluxes were around 270 µg m −2 h −1 (ca. 100 µg C m −2 h −1 ), and during most nights small negative fluxes directed from the atmosphere to the surface were observed.

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Disjunct eddy covariance technique for trace gas flux measurements

Cited by 98 publications

References 13 publications

Observations of Diurnal to Weekly Variations of Monoterpene-Dominated Fluxes of Volatile Organic Compounds from Mediterranean Forests: Implications for Regional Modeling

Observations of Diurnal to Weekly Variations of Monoterpene-Dominated Fluxes of Volatile Organic Compounds from Mediterranean Forests: Implications for Regional Modeling

Abiotic and biotic control of methanol exchanges in a temperate mixed forest

BVOC ecosystem flux measurements at a high latitude wetland site

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