Comparison of Different Algorithms for Stomatal Ozone Flux Determination from Micrometeorological Measurements

Gerosa, Giacomo; Derghi, Federico; Cieslik, S.

doi:10.1007/s11270-006-9234-7

Cited by 36 publications

(28 citation statements)

References 29 publications

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“…(5-8). Stomatal conductance peaks in the mid-morning hours and drops steadily throughout the day, consistent with estimates from other studies of water-stressed canopies Gerosa et al, 2007), and the magnitude is comparable to what has been observed in previous years at BFRS . Stomatal uptake can account for ∼29% of the daytime PAN surface conductance on average, though a plot of g st (PAN) against g c (PAN) (Fig.…”

Section: Stomatal Contribution To Apn Fluxessupporting

confidence: 90%

“…Stomatal resistance was computed using both the PenmanMonteith equation (Monteith and Unsworth, 1990) and the leaf boundary water vapor gradient approach (Thom, 1975), both of which rely on measurements of canopy-scale water vapor fluxes. Both methods yield comparable results, in agreement with recent work that has shown the two to be mathematically equivalent (Gerosa et al, 2007). Given the dry summer conditions at BFRS, we assume that the abovecanopy water vapor flux is primarily due to evapotranspiration from vegetation, except for periods during or after precipitation events (see Fig.…”

Section: Stomatal Contribution To Apn Fluxessupporting

confidence: 86%

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Eddy covariance fluxes of acyl peroxy nitrates (PAN, PPN and MPAN) above a Ponderosa pine forest

et al. 2009

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Abstract. During the Biosphere Effects on AeRosols and Photochemistry EXperiment 2007 (BEARPEX-2007), we observed eddy covariance (EC) fluxes of speciated acyl peroxy nitrates (APNs), including peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN) and peroxymethacryloyl nitrate (MPAN), above a Ponderosa pine forest in the western Sierra Nevada. All APN fluxes are net downward during the day, with a median midday PAN exchange velocity of −0.3 cm s −1 ; nighttime storage-corrected APN EC fluxes are smaller than daytime fluxes but still downward. Analysis with a standard resistance model shows that loss of PAN to the canopy is not controlled by turbulent or molecular diffusion. Stomatal uptake can account for 25 to 50% of the observed downward PAN flux. Vertical gradients in the PAN thermal decomposition (TD) rate explain a similar fraction of the flux, suggesting that a significant portion of the PAN flux into the forest results from chemical processes in the canopy. The remaining "unidentified" portion of the net PAN flux (∼15%) is ascribed to deposition or reactive uptake on nonstomatal surfaces (e.g. leaf cuticles or soil). Shifts in temperature, moisture and ecosystem activity during the summerfall transition alter the relative contribution of stomatal uptake, non-stomatal uptake and thermochemical gradients to the net PAN flux. Daytime PAN and MPAN exchange velocities are a factor of 3 smaller than those of PPN during the first two weeks of the measurement period, consistent with strong intra-canopy chemical production of PAN and MPAN Correspondence to: J. A. Thornton (thornton@atmos.washington.edu) during this period. Depositional loss of APNs can be 3-21% of the gross gas-phase TD loss depending on temperature. As a source of nitrogen to the biosphere, PAN deposition represents approximately 4-19% of that due to dry deposition of nitric acid at this site.

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Section: Stomatal Contribution To Apn Fluxessupporting

confidence: 90%

Section: Stomatal Contribution To Apn Fluxessupporting

confidence: 86%

Eddy covariance fluxes of acyl peroxy nitrates (PAN, PPN and MPAN) above a Ponderosa pine forest

et al. 2009

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“…For O 3 , it is typically derived relative to the water vapor flux, assumed to come primarily from plant transpiration. Gerosa et al (2007) have recently reviewed the two most common methods used to estimate the canopy-level stomatal resistance: (1) resistance analogies used to obtain the vapor pressure deficit at the scalar (temperature and water vapor) roughness length, z 0 0 ; which is assumed to be equivalent to that at the leaf surface (Thom, 1975;Monteith and Unsworth, 1990), denoted as the Evaporative/Resistance (ER) method:…”

Section: Discussionmentioning

confidence: 99%

Controls over ozone deposition to a high elevation subalpine forest

Turnipseed

Burns

Moore

et al. 2009

Agricultural and Forest Meteorology

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“…However, in models, its parameterization is highly uncertain because of complexities from surface conditions at sub-grid scales (Wu et al, 2011). Thus, previous studies on dry deposition calculations have primarily focused on the United States and Europe, for which observations on ozone fluxes or dry deposition velocities were available to validate either simulated ozone losses or dry deposition velocity parameterization (Rannik et al, 2012;Wu et al, 2011;Charusombat et al, 2010;Gerosa et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

An evaluation of ozone dry deposition simulations in East Asia

et al. 2014

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Abstract. We use a 3-D regional atmospheric chemistry transport model (WRF-Chem) to examine ozone dry deposition in East Asia, which is an important but uncertain research area because of insufficient observation and numerical studies focusing on East Asia. Here we compare two widely used dry deposition parameterization schemes, the Wesely and M3DRY schemes, which are used in the WRF-Chem and Community Multiscale Air Quality (CMAQ) models, respectively. Simulated ozone dry deposition velocities with the two schemes under identical meteorological conditions show considerable differences (a factor of 2) owing to surface resistance parameterization discrepancies. Resulting ozone concentrations differ by up to 10 ppbv for a monthly mean in May when the peak ozone typically occurs in East Asia. An evaluation of the simulated dry deposition velocities shows that the Wesely scheme calculates values with more pronounced diurnal variation than the M3DRY and results in a good agreement with the observations. However, we find significant changes in simulated ozone concentrations using the Wesely scheme but with different surface type data sets, indicating the high sensitivity of ozone deposition calculations to the input data. The need is high for observations to constrain the dry deposition parameterization and its input data to improve the use of air quality models for East Asia.

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Comparison of Different Algorithms for Stomatal Ozone Flux Determination from Micrometeorological Measurements

Cited by 36 publications

References 29 publications

Eddy covariance fluxes of acyl peroxy nitrates (PAN, PPN and MPAN) above a Ponderosa pine forest

Eddy covariance fluxes of acyl peroxy nitrates (PAN, PPN and MPAN) above a Ponderosa pine forest

Controls over ozone deposition to a high elevation subalpine forest

An evaluation of ozone dry deposition simulations in East Asia

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