Eddy Covariance Flux Measurements of NH<sub>3</sub> and NO<sub>y</sub> with a Dual-Channel Thermal Converter

Ammann, Christof; Jocher, Markus; Voglmeier, Karl

doi:10.1109/metroagrifor.2019.8909278

Cited by 2 publications

(1 citation statement)

References 22 publications

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“…Although wet deposition is relatively straightforward to measure, the accurate quantification of dry N deposition remains a challenge. Recent progress in fast and robust measurement techniques allows for the investigation of the temporal dynamics in concentrations and dry deposition fluxes (using the eddy covariance (EC) approach) for total reactive nitrogen ( N r ) (Marx et al, 2012;Ammann et al, 2012;Brümmer et al, 2013Brümmer et al, , 2022aZöll et al, 2019;Ammann et al, 2019;Wintjen et al, 2020Wintjen et al, , 2022 and its individual compounds, e.g., for NH 3 (Whitehead et al, 2008;Ferrara et al, 2012Ferrara et al, , 2021Moravek et al, 2020). For N r , the Total Reactive Atmospheric Nitrogen Converter (TRANC) (Marx et al, 2012) coupled to a chemiluminescence detector (CLD) has shown its suitability for flux measurements in various field applications (see references for N r above).…”

Section: Introductionmentioning

confidence: 99%

Forest–atmosphere exchange of reactive nitrogen in a remote region – Part II: Modeling annual budgets

Wintjen¹,

Schrader²,

Schaap³

et al. 2022

Biogeosciences

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Abstract. To monitor the effect of current nitrogen emissions and mitigation strategies, total (wet + dry) atmospheric nitrogen deposition to forests is commonly estimated using chemical transport models or canopy budget models in combination with throughfall measurements. Since flux measurements of reactive nitrogen (Nr) compounds are scarce, dry deposition process descriptions as well as the calculated flux estimates and annual budgets are subject to considerable uncertainties. In this study, we compared four different approaches to quantify annual dry deposition budgets of total reactive nitrogen (ΣNr) at a mixed forest site situated in the Bavarian Forest National Park, Germany. Dry deposition budgets were quantified based on (I) 2.5 years of eddy covariance flux measurements with the Total Reactive Atmospheric Nitrogen Converter (TRANC); (II) an in situ application of the bidirectional inferential flux model DEPAC (Deposition of Acidifying Compounds), here called DEPAC-1D; (III) a simulation with the chemical transport model LOTOS-EUROS (Long-Term Ozone Simulation – European Operational Smog) v2.0, using DEPAC as dry deposition module; and (IV) a canopy budget technique (CBT). Averaged annual ΣNr dry deposition estimates determined from TRANC measurements were 4.7 ± 0.2 and 4.3 ± 0.4 kg N ha−1 a−1, depending on the gap-filling approach. DEPAC-1D-modeled dry deposition, using concentrations and meteorological drivers measured at the site, was 5.8 ± 0.1 kg N ha−1 a−1. In comparison to TRANC fluxes, DEPAC-1D estimates were systematically higher during summer and in close agreement in winter. Modeled ΣNr deposition velocities (vd) of DEPAC-1D were found to increase with lower temperatures and higher relative humidity and in the presence of wet leaf surfaces, particularly from May to September. This observation was contrary to TRANC-observed fluxes. LOTOS-EUROS-modeled annual dry deposition was 6.5 ± 0.3 kg N ha−1 a−1 for the site-specific weighting of land-use classes within the site's grid cell. LOTOS-EUROS showed substantial discrepancies to measured ΣNr deposition during spring and autumn, which was related to an overestimation of ammonia (NH3) concentrations by a factor of 2 to 3 compared to measured values as a consequence of a mismatch between gridded input NH3 emissions and the site's actual (rather low) pollution climate. According to LOTOS-EUROS predictions, ammonia contributed most to modeled input ΣNr concentrations, whereas measurements showed NOx as the prevailing compound in ΣNr concentrations. Annual deposition estimates from measurements and modeling were in the range of minimum and maximum estimates determined from CBT being at 3.8 ± 0.5 and 6.7 ± 0.3 kg N ha−1 a−1, respectively. By adding locally measured wet-only deposition, we estimated an annual total nitrogen deposition input between 11.5 and 14.8 kg N ha−1 a−1, which is within the critical load ranges proposed for deciduous and coniferous forests.

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Section: Introductionmentioning

confidence: 99%

Forest–atmosphere exchange of reactive nitrogen in a remote region – Part II: Modeling annual budgets

Wintjen¹,

Schrader²,

Schaap³

et al. 2022

Biogeosciences

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Validation of a Short-Range Dispersion and Deposition Model Using Field-Scale Ammonia and Methane Release Experiments

Häni,

Neftel,

Flechard

et al. 2024

Preprint

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Eddy Covariance Flux Measurements of NH₃ and NO_y with a Dual-Channel Thermal Converter

Cited by 2 publications

References 22 publications

Forest–atmosphere exchange of reactive nitrogen in a remote region – Part II: Modeling annual budgets

Forest–atmosphere exchange of reactive nitrogen in a remote region – Part II: Modeling annual budgets

Validation of a Short-Range Dispersion and Deposition Model Using Field-Scale Ammonia and Methane Release Experiments

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Eddy Covariance Flux Measurements of NH3 and NOy with a Dual-Channel Thermal Converter

Cited by 2 publications

References 22 publications

Forest–atmosphere exchange of reactive nitrogen in a remote region – Part II: Modeling annual budgets

Forest–atmosphere exchange of reactive nitrogen in a remote region – Part II: Modeling annual budgets

Validation of a Short-Range Dispersion and Deposition Model Using Field-Scale Ammonia and Methane Release Experiments

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Eddy Covariance Flux Measurements of NH₃ and NO_y with a Dual-Channel Thermal Converter