Sulfate dry deposition fluxes and overall deposition velocities measured with a surrogate surface

2002 ◽  
Vol 297 (1-3) ◽  
pp. 193-201 ◽  
Author(s):  
Mustafa Odabasi ◽  
H. Ozgur Bagiroz
Keyword(s):  
Dry Deposition ◽  
Deposition Fluxes ◽  
Surrogate Surface ◽  
Deposition Velocities

scholarly journals New Methodology Shows Short Atmospheric Lifetimes of Oxidized Sulfur and Nitrogen due to Dry Deposition

2021 ◽  
Author(s):  
Katherine Hayden ◽  
Shao-Meng Li ◽  
Paul Makar ◽  
John Liggio ◽  
Samar G. Moussa ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Dry Deposition ◽  
Deposition Velocity ◽  
Monte Carlo Analysis ◽  
Climate Impacts ◽  
Atmospheric Pollutants ◽  
Transport Models ◽  
Deposition Fluxes ◽  
Deposition Velocities ◽  
Model Algorithm

Abstract. The atmospheric lifetimes of pollutants determine their impacts on human health, ecosystems and climate and yet pollutant lifetimes due to dry deposition over large regions have not been determined from measurements. Here, a new methodology based on aircraft observations is used to determine the lifetimes of oxidized sulfur and nitrogen due to dry deposition over (3–6) × 103 km2 of boreal forest in Canada. Dry deposition fluxes decreased exponentially with distance, resulting in lifetimes of 2.2–26 hours. Fluxes were 2–14 and 1–18 times higher than model estimates for oxidized sulfur and nitrogen, respectively, indicating dry deposition velocities which were 1.2–5.4 times higher than those computed for models. A Monte-Carlo analysis with five commonly used inferential dry deposition algorithms indicates that such model underestimates of dry deposition velocity are typical. These findings indicate that deposition to vegetation surfaces are likely under-estimated in regional and global chemical transport models regardless of the model algorithm used. The model-observation gaps may be reduced if surface pH, and quasi-laminar and aerodynamic resistances in algorithms are optimized as shown in the Monte-Carlo analysis. Assessing the air quality and climate impacts of atmospheric pollutants on regional and global scales requires improved measurement-based understanding of atmospheric lifetimes of these pollutants.

scholarly journals Dry deposition of nitrogen compounds (NO<sub>2</sub>, HNO<sub>3</sub>, NH<sub>3</sub>), sulfur dioxide and ozone in West and Central African ecosystems using the inferential method

2013 ◽  
Vol 13 (5) ◽  
pp. 11689-11744 ◽  
Author(s):  
M. Adon ◽  
C. Galy-Lacaux ◽  
V. Yoboue ◽  
C. Delon ◽  
F. Solmon ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Nitrogen Compounds ◽  
Deposition Flux ◽  
Deposition Fluxes ◽  
Deposition Velocities ◽  
Latitudinal Transect ◽  
Inferential Method ◽  
Surface Measurements ◽  
Remote Sites ◽  
Big Leaf Model

Abstract. This work is part of the IDAF program (IGAC-DEBITS-AFRICA) and is based on the long term monitoring of gas concentrations (1998–2007) established on seven remote sites representative of major African ecosystems. Dry deposition fluxes were estimated by the inferential method using on one hand surface measurements of gas concentrations (NO2, HNO3, NH3, SO2, and O3) and on the other hand simulated dry deposition velocities (Vd). Vd were calculated using the big-leaf model of Zhang et al. (2003b). In the model of deposition, surface and meteorological conditions specific to IDAF sites have been adapted in order to simulate Vd representative of major African ecosystems. The monthly, seasonal and annual mean variations of gaseous dry deposition fluxes (NO2, HNO3, NH3, O3, and SO2) are analyzed. Along the latitudinal transect of ecosystems, the annual mean dry deposition fluxes of nitrogen compounds range from 0.4 ± 0.0 to 0.8 ± 0.2 kg N ha−1 yr−1 for NO2, from 0.7 ± 0.1 to 1.0 ± 0.3 kg N ha−1 yr−1 for HNO3, and from 2.3 ± 0.8 to 10.5 ± 5.0 kg N ha−1 yr−1 for NH3 over the study period (1998–2007). The total nitrogen dry deposition flux (NO2+HNO3+NH3) is more important in forests (11.2–11.8 kg N ha−1 yr−1) than in wet and dry savannas (3.4–5.3 kg N ha−1 yr−1). NH3 dominated nitrogen dry deposition, representing 67–80% of the total. The annual mean dry deposition fluxes of ozone range between 11.3 ± 4.7 and 17.5 ± 3.0 kg ha−1 yr−1 in dry savannas, 17.5 ± 3.0 and 19.2 ± 2.9 kg ha−1 yr−1 in wet savannas, and 10.6 ± 2.0 and 13.2 ± 3.6 kg ha−1 yr−1 in forests. Lowest O3 dry deposition fluxes in forests are correlated to low measured O3 concentrations, lower of a factor of 2–3, compared to others ecosystems. Along the ecosystem transect, annual mean of SO2 dry deposition fluxes present low values and a small variability (0.5 to 1 kg S ha−1 yr−1). No specific trend in the interannual variability of these gaseous dry deposition fluxes is observed over the study period.

scholarly journals Dry deposition fluxes and deposition velocities of seven trace metal species at five sites in central Taiwan – a summary of surrogate surface measurements and a comparison with model estimations

2012 ◽  
Vol 12 (7) ◽  
pp. 3405-3417 ◽  
Author(s):  
L. Zhang ◽  
G. C. Fang ◽  
C. K. Liu ◽  
Y. L. Huang ◽  
J. H. Huang ◽  
...  
Keyword(s):  
Dry Deposition ◽  
The Other ◽  
Metal Species ◽  
Annual Average ◽  
Deposition Fluxes ◽  
Deposition Model ◽  
Deposition Velocities ◽  
Flux Measurements ◽  
Dry Deposition Model ◽  
Central Taiwan

Abstract. Daily air concentrations and dry deposition fluxes of seven metal species were monitored at five sites in central Taiwan for five or six days every month from September 2009 to August 2010. Annual average concentrations at the five sites were in the range of 2.8 to 3.6 ng m−3 for As, 25 to 82 ng m−3 for Mn, 1900 to 2800 ng m−3 for Fe, 69 to 109 ng m−3 for Zn, 18 to 33 ng m−3 for Cr, 60 to 110 ng m−3 for Cu, and 25 to 40 ng m−3 for Pb. Annual average dry deposition fluxes were on the order of 3, 20, 400, 50, 25, 50, and 50 μg m−2 day−1 for As, Mn, Fe, Zn, Cr, Cu, and Pb, respectively. Annual average dry deposition velocities (Vd) for the seven metal species ranged from 0.18 to 2.22 cm s−1 at these locations. Small seasonal and geographical variations, e.g. from a few percent to a factor of 2 for different species and/or at different locations, were found in the measured concentrations, fluxes, and Vds. The measured fluxes and air concentrations had moderate to good correlations for several of the species at several of the sites (e.g. Fe, Zn, and Mn at most of the sites), but had either weak or no correlations for the other species or at the other sites (e.g. As at Sites I and III, Zn and Cr at Site IV, and Cu at most of the sites). The latter cases were believed to have large uncertainties in the flux measurements using surrogate surfaces. Sensitivity tests were conducted for particle Vds using a size-segregated particle dry deposition model, assuming various combinations of three lognormal size distributions representing fine particles (PM2.5), coarse particles (PM2.5–10), and super-sized particles (PM10+), respectively. It was found that the measured dry deposition fluxes can be reproduced reasonably well using the size-segregated particle dry deposition model if the mass fractions of the metal species in PM2.5, PM2.5–10 and PM10+ were known. Significant correlations between the modeled and the measured daily fluxes were found for those cases that were believed to have small uncertainties in the flux measurements.

scholarly journals Determination of the Sampler Type and Rainfall Effect on the Deposition Fluxes of the Polychlorinated Biphenyls

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Askin Birgül ◽  
Yücel Tasdemir
Keyword(s):  
Dry Deposition ◽  
Polychlorinated Biphenyl ◽  
Sampling Site ◽  
Bulk Deposition ◽  
Atmospheric Concentration ◽  
Deposition Fluxes ◽  
Measured Flux ◽  
Deposition Velocities ◽  
Average Flux

Atmospheric concentration and deposition samples were collected between June 2008 and June 2009 in an urban sampling site Yavuzselim, Turkey. Eighty-three polychlorinated biphenyl (PCB) congeners were targeted in the collected samples. It was found that 90% of the total PCB concentration was in the gas phase. Deposition samples were collected by a wet-dry deposition sampler (WDDS) and a bulk deposition sampler (BDS). Average total deposition fluxes measured with the BDS in dry periods was5500±2400 pg/(m2day); average dry deposition fluxes measured by the WDDS in the same period were6400±3300 pg/(m2day). The results indicated that the sampler type affected the measured flux values. Bulk deposition samples were also collected in rainy periods by using the BDS and the average flux value was8700±3100 pg/(m2day). The measured flux values were lower than the values reported for the urban and industrial areas. Dry deposition velocities for the WDDS and BDS samples were calculated0.48±0.35 cm/s and0.13±0.15 cm/s, respectively.

scholarly journals Dry deposition fluxes and deposition velocities of seven trace metal species at five sites in Central Taiwan - a summary of surrogate surface measurements and a comparison with model estimation

2011 ◽  
Vol 11 (12) ◽  
pp. 32847-32875 ◽  
Author(s):  
L. Zhang ◽  
G. C. Fang ◽  
C. K. Liu ◽  
Y. L. Huang ◽  
J. H. Huang ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Metal Species ◽  
Annual Average ◽  
Deposition Fluxes ◽  
Deposition Model ◽  
Deposition Velocities ◽  
Flux Measurements ◽  
Dry Deposition Model ◽  
Central Taiwan ◽  
Air Concentrations

Abstract. Daily air concentrations and dry deposition fluxes of seven metal species were monitored at five sites in Central Taiwan for five or six days each month from September 2009 to August 2010. Annual average concentrations at the five sites were in the range of 2.8 to 3.6 ng m−3 for As, 25 to 82 ng m−3 for Mn, 1900 to 2800 ng m−3 for Fe, 69 to 109 ng m−3 for Zn, 18 to 33 ng m−3 for Cr, 60 to 110 ng m−3 for Cu, and 25 to 40 ng m−3 for Pb. Annual average dry deposition fluxes were on the order of 3, 20, 400, 50, 25, 50 and 50 μg m−2 day−1 for As, Mn, Fe, Zn, Cr, Cu and Pb, respectively. Annual average dry deposition velocities (Vd) for the seven metal species ranged from 0.18 to 2.22 cm s−1 at these locations. Small seasonal and geographical variations, e.g., from a few percent to a factor of 2 for different species and/or at different locations, were found for measured concentrations, fluxes and Vd. Measured fluxes and air concentrations had moderate to good correlations for several species at several sites, but had weak or no correlations for other species or at other sites, the latter cases were believed to have large uncertainties in flux measurements using surrogate surfaces. Sensitivity tests were conducted for particle Vd using a size-segregated particle dry deposition model, assuming various combinations of three lognormal size distributions representing fine particles (PM2.5), coarse particles (PM2.5-10) and super size particles (PM10+), respectively. It was found that measured dry deposition fluxes can be reproduced reasonably well using the size-segregated particle dry deposition model if the mass fractions of metal species in PM2.5, PM2.5-10 and PM10+ were known. Significant correlations between modeled and measured daily fluxes were found for those cases that were believed to have small uncertainties in flux measurements.

scholarly journals Dry deposition of nitrogen compounds (NO<sub>2</sub>, HNO<sub>3</sub>, NH<sub>3</sub>), sulfur dioxide and ozone in west and central African ecosystems using the inferential method

2013 ◽  
Vol 13 (22) ◽  
pp. 11351-11374 ◽  
Author(s):  
M. Adon ◽  
C. Galy-Lacaux ◽  
C. Delon ◽  
V. Yoboue ◽  
F. Solmon ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Nitrogen Compounds ◽  
Deposition Flux ◽  
Deposition Fluxes ◽  
Deposition Velocities ◽  
Inferential Method ◽  
Surface Measurements ◽  
Remote Sites ◽  
Big Leaf Model ◽  
The One

Abstract. This work is part of the IDAF program (IGAC-DEBITS-AFRICA) and is based on the long-term monitoring of gas concentrations (1998–2007) established at seven remote sites representative of major African ecosystems. Dry deposition fluxes were estimated by the inferential method using on the one hand surface measurements of gas concentrations (NO2, HNO3, NH3, SO2 and O3) and on the other hand modeled exchange rates. Dry deposition velocities (Vd) were calculated using the big-leaf model of Zhang et al. (2003b). The bidirectional approach is used for NH3 surface–atmosphere exchange (Zhang et al., 2010). Surface and meteorological conditions specific to IDAF sites have been used in the models of deposition. The seasonal and annual mean variations of gaseous dry deposition fluxes (NO2, HNO3, NH3, O3 and SO2) are analyzed. Along the latitudinal transect of ecosystems, the annual mean dry deposition fluxes of nitrogen compounds range from −0.4 to −0.8 kg N ha−1 yr−1 for NO2, from −0.7 to −1.0 kg N ha−1 yr−1 for HNO3 and from −0.7 to −8.3 kg N ha−1 yr−1 for NH3 over the study period (1998–2007). The total nitrogen dry deposition flux (NO2+HNO3+NH3) is more important in forests (−10 kg N ha−1 yr−1) than in wet and dry savannas (−1.6 to −3.9 kg N ha−1 yr−1). The annual mean dry deposition fluxes of ozone range between −11 and −19 kg ha−1 yr−1 in dry and wet savannas, and −11 and −13 kg ha−1 yr−1 in forests. Lowest O3 dry deposition fluxes in forests are correlated to low measured O3 concentrations, lower by a factor of 2–3, compared to other ecosystems. Along the ecosystem transect, the annual mean of SO2 dry deposition fluxes presents low values and a small variability (−0.5 to −1 kg S ha−1 yr−1). No specific trend in the interannual variability of these gaseous dry deposition fluxes is observed over the study period.

scholarly journals Estimation of speciated and total mercury dry deposition at monitoring locations in Eastern and Central North America

2012 ◽  
Vol 12 (1) ◽  
pp. 2783-2815 ◽  
Author(s):  
L. Zhang ◽  
P. Blanchard ◽  
D. A. Gay ◽  
E. M. Prestbo ◽  
M. R. Risch ◽  
...  
Keyword(s):  
North America ◽  
Dry Deposition ◽  
Regional Scale ◽  
Elemental Mercury ◽  
Field Studies ◽  
Relative Magnitude ◽  
Point Sources ◽  
Gaseous Elemental Mercury ◽  
Surrogate Surface ◽  
Deposition Velocities

Abstract. Dry deposition of speciated mercury, i.e., gaseous oxidized mercury (GOM), particulate bound mercury (PBM), and gaseous elemental mercury (GEM), was estimated for the year 2008–2009 at 19 monitoring locations in Eastern and Central North America. Dry deposition estimates were obtained by combining monitored 2–4 hourly speciated ambient concentration with modeled hourly dry deposition velocities (Vd) calculated using forecasted meteorology. Annual dry deposition of GOM + PBM was estimated to be in the range of 0.4 to 8.1 μg m−2 at these locations with GOM deposition being mostly 5 to 10 times higher than PBM deposition, due to their different Vd values. Net annual GEM dry deposition was estimated to be in the range of 5 to 26 μg m−2 at 18 sites and 33 μg m−2 at one site. The estimated dry deposition agrees very well with limited surrogate-surface dry deposition measurements of GOM and PBM, and also agrees with litterfall mercury measurements conducted at multiple locations in Eastern and Central North America. This study suggests that GEM contributes much more than GOM + PBM to the total dry deposition at the majority of sites considered here; the only exception is at locations close to significant point sources where GEM and GOM + PBM contribute equally to the total dry deposition. The relative magnitude of the speciated dry deposition and their good comparison with litterfall deposition suggest that mercury in litterfall primarily originates from GEM, consistent with previous limited field studies. The study also supports previous analyses suggesting that total dry deposition of mercury is equally if not more important as wet deposition of mercury on a regional scale in Eastern North America.

scholarly journals Observation- and model-based estimates of particulate dry nitrogen deposition to the oceans

2017 ◽  
Vol 17 (13) ◽  
pp. 8189-8210 ◽  
Author(s):  
Alex R. Baker ◽  
Maria Kanakidou ◽  
Katye E. Altieri ◽  
Nikos Daskalakis ◽  
Gregory S. Okin ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Observational Data ◽  
Atmospheric Chemistry ◽  
Dry Deposition ◽  
N Deposition ◽  
Northwest Pacific ◽  
Deposition Flux ◽  
Northern Indian Ocean ◽  
Deposition Fluxes ◽  
Deposition Velocities

Abstract. Anthropogenic nitrogen (N) emissions to the atmosphere have increased significantly the deposition of nitrate (NO3−) and ammonium (NH4+) to the surface waters of the open ocean, with potential impacts on marine productivity and the global carbon cycle. Global-scale understanding of the impacts of N deposition to the oceans is reliant on our ability to produce and validate models of nitrogen emission, atmospheric chemistry, transport and deposition. In this work,  ∼  2900 observations of aerosol NO3− and NH4+ concentrations, acquired from sampling aboard ships in the period 1995–2012, are used to assess the performance of modelled N concentration and deposition fields over the remote ocean. Three ocean regions (the eastern tropical North Atlantic, the northern Indian Ocean and northwest Pacific) were selected, in which the density and distribution of observational data were considered sufficient to provide effective comparison to model products. All of these study regions are affected by transport and deposition of mineral dust, which alters the deposition of N, due to uptake of nitrogen oxides (NOx) on mineral surfaces. Assessment of the impacts of atmospheric N deposition on the ocean requires atmospheric chemical transport models to report deposition fluxes; however, these fluxes cannot be measured over the ocean. Modelling studies such as the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP), which only report deposition flux, are therefore very difficult to validate for dry deposition. Here, the available observational data were averaged over a 5° × 5° grid and compared to ACCMIP dry deposition fluxes (ModDep) of oxidised N (NOy) and reduced N (NHx) and to the following parameters from the Tracer Model 4 of the Environmental Chemical Processes Laboratory (TM4): ModDep for NOy, NHx and particulate NO3− and NH4+, and surface-level particulate NO3− and NH4+ concentrations. As a model ensemble, ACCMIP can be expected to be more robust than TM4, while TM4 gives access to speciated parameters (NO3− and NH4+) that are more relevant to the observed parameters and which are not available in ACCMIP. Dry deposition fluxes (CalDep) were calculated from the observed concentrations using estimates of dry deposition velocities. Model–observation ratios (RA, n), weighted by grid-cell area and number of observations, were used to assess the performance of the models. Comparison in the three study regions suggests that TM4 overestimates NO3− concentrations (RA, n =  1.4–2.9) and underestimates NH4+ concentrations (RA, n =  0.5–0.7), with spatial distributions in the tropical Atlantic and northern Indian Ocean not being reproduced by the model. In the case of NH4+ in the Indian Ocean, this discrepancy was probably due to seasonal biases in the sampling. Similar patterns were observed in the various comparisons of CalDep to ModDep (RA, n =  0.6–2.6 for NO3−, 0.6–3.1 for NH4+). Values of RA, n for NHx CalDep–ModDep comparisons were approximately double the corresponding values for NH4+ CalDep–ModDep comparisons due to the significant fraction of gas-phase NH3 deposition incorporated in the TM4 and ACCMIP NHx model products. All of the comparisons suffered due to the scarcity of observational data and the large uncertainty in dry deposition velocities used to derive deposition fluxes from concentrations. These uncertainties have been a major limitation on estimates of the flux of material to the oceans for several decades. Recommendations are made for improvements in N deposition estimation through changes in observations, modelling and model–observation comparison procedures. Validation of modelled dry deposition requires effective comparisons to observable aerosol-phase species' concentrations, and this cannot be achieved if model products only report dry deposition flux over the ocean.

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