Aerosol particle dry deposition to canopy and forest floor measured by two‐layer eddy covariance system

Grönholm, Tiia; Launiainen, Samuli; Ahlm, Lars; Mårtensson, E. M.; Kulmala, Markku; Vesala, Timo; Nilsson, E. Douglas

doi:10.1029/2008jd010663

Cited by 36 publications

(56 citation statements)

References 63 publications

(97 reference statements)

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“…However, qualitatively, our findings regarding the PZ10 performance for coniferous forests are in accordance with those reported by Petroff and Zhang (2010). They reported that the PZ10 parameterization underpredicted the measured deposition velocities for the subset of observations that we also investigated for coniferous forest - Lamaud et al (1994), Gallagher et al (1997), Buzorious et al (2000), Gaman et al (2004) -and overpredicted for Grönholm et al (2009).…”

Section: Discussionsupporting

confidence: 80%

“…Measurements conducted over grass by Wesely et al (1977), Neumann and den Hartog (1985), Allen et al (1991), Nemitz et al (2002), and Vong et al (2004) were used to evaluate the performance of the five parameterizations. For coniferous forest, modeled deposition velocities were compared with measurements from Lamaud et al (1994), Wyzers and Duyzer (1996), Gallagher et al (1997), Ruijgrok et al (1997), Buzorius et al (2000), Rannik et al (2000), Gaman et al (2004), Pryor et al (2007), and Grönholm et al (2009). Experiments conducted over deciduous forest are limited, and only three studies (Wesely et al, 1983;Pryor, 2006;Matsuda et al, 2010) were used in the present paper.…”

Section: An Evaluation Of the Dry Deposition Parameterizationsmentioning

confidence: 99%

“…Nine studies conducted on coniferous forest (Lamaud et al, 1994;Wyers and Duyzers, 1997;Gallagher et al, 1997;Ruijgrok et al, 1997;Rannik et al, 2000;Buzorious et al, 2000;Gaman et al, 2004;Pryor et al, 2007;and Grönholm et al, 2009) were used to evaluate the accuracy of the parameterizations. In these studies, the largest variations (ranges are given in the parentheses) were associated with u * (0.06-1.30 m s −1 ), U (0.60-6.19 m s −1 ), LAI (6-10 m 2 m −2 ), and d p (0.01-0.60 µm).…”

Section: Evaluation Of Dry Deposition To Coniferous Forestmentioning

confidence: 99%

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Evaluation of five dry particle deposition parameterizations for incorporation into atmospheric transport models

Khan

Perlinger

2017

Geosci. Model Dev.

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Abstract. Despite considerable effort to develop mechanistic dry particle deposition parameterizations for atmospheric transport models, current knowledge has been inadequate to propose quantitative measures of the relative performance of available parameterizations. In this study, we evaluated the performance of five dry particle deposition parameterizations developed by Zhang et al. (2001) ("Z01"), Petroff and Zhang (2010) ("PZ10"), Kouznetsov and Sofiev (2012) ("KS12"), Zhang and He (2014) ("ZH14"), and Zhang and Shao (2014) ("ZS14"), respectively. The evaluation was performed in three dimensions: model ability to reproduce observed deposition velocities, V d (accuracy); the influence of imprecision in input parameter values on the modeled V d (uncertainty); and identification of the most influential parameter(s) (sensitivity). The accuracy of the modeled V d was evaluated using observations obtained from five land use categories (LUCs): grass, coniferous and deciduous forests, natural water, and ice/snow. To ascertain the uncertainty in modeled V d , and quantify the influence of imprecision in key model input parameters, a Monte Carlo uncertainty analysis was performed. The Sobol' sensitivity analysis was conducted with the objective to determine the parameter ranking from the most to the least influential. Comparing the normalized mean bias factors (indicators of accuracy), we find that the ZH14 parameterization is the most accurate for all LUCs except for coniferous forest, for which it is second most accurate. From Monte Carlo simulations, the estimated mean normalized uncertainties in the modeled V d obtained for seven particle sizes (ranging from 0.005 to 2.5 µm) for the five LUCs are 17, 12, 13, 16, and 27 % for the Z01, PZ10, KS12, ZH14, and ZS14 parameterizations, respectively. From the Sobol' sensitivity results, we suggest that the parameter rankings vary by particle size and LUC for a given parameterization. Overall, for d p = 0.001 to 1.0 µm, friction velocity was one of the three most influential parameters in all parameterizations. For giant particles (d p = 10 µm), relative humidity was the most influential parameter. Because it is the least complex of the five parameterizations, and it has the greatest accuracy and least uncertainty, we propose that the ZH14 parameterization is currently superior for incorporation into atmospheric transport models.

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Section: Discussionsupporting

confidence: 80%

Section: An Evaluation Of the Dry Deposition Parameterizationsmentioning

confidence: 99%

Section: Evaluation Of Dry Deposition To Coniferous Forestmentioning

confidence: 99%

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Evaluation of five dry particle deposition parameterizations for incorporation into atmospheric transport models

Khan

Perlinger

2017

Geosci. Model Dev.

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“…To further investigate the actual emission process, particle number fluxes should be measured simultaneously in and above the canopy, similar to the study by Grönholm et al (2009). This type of measurements could reveal whether the wind actually triggers the emission, or if the correlation between net upward particle fluxes and wind speed results from storage and ventilation processes.…”

Section: Diurnal Cycles Of Fluxes Of Particles With Diametersmentioning

confidence: 99%

Emission and dry deposition of accumulation mode particles in the Amazon Basin

et al. 2010

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Abstract. Size-resolved vertical aerosol number fluxes of particles in the diameter range 0.25-2.5 µm were measured with the eddy covariance method from a 53 m high tower over the Amazon rain forest, 60 km NNW of Manaus, Brazil. This study focuses on data measured during the relatively clean wet season, but a shorter measurement period from the more polluted dry season is used as a comparison. Size-resolved net particle fluxes of the five lowest size bins, representing 0.25-0.45 µm in diameter, were in general dominated by deposition in more or less all wind sectors in the wet season. This is an indication that the source of primary biogenic aerosol particles may be small in this particle size range. Transfer velocities within this particle size range were observed to increase linearly with increasing friction velocity and increasing particle diameter.In the diameter range 0.5-2.5 µm, vertical particle fluxes were highly dependent on wind direction. In wind sectors where anthropogenic influence was low, net upward fluxes were observed. However, in wind sectors associated with higher anthropogenic influence, deposition fluxes dominated. The net upward fluxes were interpreted as a result of primary biogenic aerosol emission, but deposition of anthropogenic particles seems to have masked this emission in wind sectors with higher anthropogenic influence. The net emission fluxes were at maximum in the afternoon when the mixed layer is well developed, and were best correlated with horizontal wind speed according to the equationwhere F is the net emission number flux of 0.5-2.5 µm particles [m −2 s −1 ] and U is the horizontal wind speed [ms −1 ] at the top of the tower.

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“…Particles may have been lost within the canopy by dry deposition before reaching the inlet (Grönholm et al, 2007;Buzorius et al, 2003;Petroff et al, 2008), which includes removal through Brownian diffusion (mainly for fine mode particles below D p < 100 nm) or through impaction or interception (mainly for coarse mode particles above D p > 1000 nm). Grönholm et al (2009) performed aerosol flux measurements using the eddy covariance technique at Hyytiälä and found that only 35 % of the particles penetrated through the canopy at low wind speeds. At higher wind speeds and correspondingly stronger turbulent conditions only 10 % of all particles reached the ground.…”

Section: Particle Lossesmentioning

confidence: 99%

Low hygroscopic scattering enhancement of boreal aerosol and the implications for a columnar optical closure study

et al. 2015

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Abstract. Ambient aerosol particles can take up water and thus change their optical properties depending on the hygroscopicity and the relative humidity (RH) of the surrounding air. Knowledge of the hygroscopicity effect is of crucial importance for radiative forcing calculations and is also needed for the comparison or validation of remote sensing or model results with in situ measurements. Specifically, particle light scattering depends on RH and can be described by the scattering enhancement factor f (RH), which is defined as the particle light scattering coefficient at defined RH divided by its dry value (RH < 30-40 %).Here, we present results of an intensive field campaign carried out in summer 2013 at the SMEAR II station at Hyytiälä, Finland. Ground-based and airborne measurements of aerosol optical, chemical and microphysical properties were conducted. The f (RH) measured at ground level by a humidified nephelometer is found to be generally lower (e.g. 1.63 ± 0.22 at RH = 85 % and λ = 525 nm) than observed at other European sites. One reason is the high organic mass fraction of the aerosol encountered at Hyytiälä to which f (RH) is clearly anti-correlated (R 2 ≈ 0.8). A simplified parametrization of f (RH) based on the measured chemical mass fraction can therefore be derived for this aerosol type. A trajectory analysis revealed that elevated values of f (RH) and the corresponding elevated inorganic mass fraction are partially caused by transported hygroscopic sea spray particles. An optical closure study shows the consistency of the ground-based in situ measurements.Our measurements allow to determine the ambient particle light extinction coefficient using the measured f (RH). By combining the ground-based measurements with intensive aircraft measurements of the particle number size distribution and ambient RH, columnar values of the particle extinction coefficient are determined and compared to columnar measurements of a co-located AERONET sun photometer. The water uptake is found to be of minor importance for the column-averaged properties due to the low particle hygroscopicity and the low RH during the daytime of the summer months. The in situ derived aerosol optical depths (AOD) clearly correlate with directly measured values of the sun photometer but are substantially lower compared to the directly measured values (factor of ∼ 2-3). The comparison degrades for longer wavelengths. The disagreement between in situ derived and directly measured AOD is hypothesized Published by Copernicus Publications on behalf of the European Geosciences Union. 7248 P. Zieger et al.: Scattering enhancement of boreal aerosol and columnar closure study to originate from losses of coarse and fine mode particles through dry deposition within the canopy and losses in the in situ sampling lines. In addition, elevated aerosol layers (above 3 km) from long-range transport were observed using an aerosol lidar at Kuopio, Finland, about 200 km east-northeast of Hyytiälä. These elevated layers further explain parts of the disagree...

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Aerosol particle dry deposition to canopy and forest floor measured by two‐layer eddy covariance system

Cited by 36 publications

References 63 publications

Evaluation of five dry particle deposition parameterizations for incorporation into atmospheric transport models

Evaluation of five dry particle deposition parameterizations for incorporation into atmospheric transport models

Emission and dry deposition of accumulation mode particles in the Amazon Basin

Low hygroscopic scattering enhancement of boreal aerosol and the implications for a columnar optical closure study

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