scholarly journals Environmental effect of heavy metals deposition in arid city

2019 ◽  
Keyword(s):  
Heavy Metals ◽  
Dry Deposition ◽  
Arid Region ◽  
Wet Deposition ◽  
Environmental Effect ◽  
Deposition Flux ◽  
Rain Event ◽  
Heating Period ◽  
Deposition Fluxes ◽  
Wet Deposition Flux

<p>This paper analysis the contents and variation of heavy metals in wet and dry deposition in Changji (Xinjiang, China) revealed their reducing regularity for heavy metals in atmosphere in arid area. Samples (including 84 dry deposition samples and 16 wet deposition samples) were collected from January 2016 to December 2016, and the contents of heavy metals (Ni, Cu, Cd and Pb) were analyzed by AA-7000 atomic absorption spectrophotometer. The dry deposition fluxes of Ni, Cu, Cd and Pb are 3.70 mg/( m2.a), 4.81 mg/( m2. a), 0.53 mg/( m2•a) and 22.74 mg/( m2•a), respectively; the wet deposition fluxes of Ni, Cu, Cd and Pb are 0.77mg/( m2•a), 3.25mg/( m2•a), 0.04mg/( m2•a) and 0.11mg/( m2•a), respectively. Each of the four heavy metals deposition fluxes during heating period was higher than non-heating period, especially for Pb and Cd, which is mainly due to the emission of coal combustion for heating. During sampling periods, the ratio of wet deposition flux to total for Ni, Cu, Cd and Pb are 17.21%, 40.33%, 7.67% and 0.48%, respectively; the wet deposition flux is far less than dry deposition, especially for Pb. The rate of dry deposition is lower than wet deposition, however dry deposition plays an important role in scavenging heavy metals in arid region. Arid region has a low intensity and frequency of rain event, heavy metals were mainly scavenging by dry deposition attribute to its continuous and dependable process. Dry deposition has much more environmental effect on heavy metal in arid region.</p>

scholarly journals Subtropical subsidence and surface deposition of oxidized mercury produced in the free troposphere

2017 ◽  
Vol 17 (14) ◽  
pp. 8999-9017 ◽  
Author(s):  
Viral Shah ◽  
Lyatt Jaeglé
Keyword(s):  
Boundary Layer ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Transport Model ◽  
Lower Troposphere ◽  
Deposition Flux ◽  
Surface Deposition ◽  
Middle Troposphere ◽  
Western Us ◽  
Wet Deposition Flux

Abstract. Oxidized mercury (Hg(II)) is chemically produced in the atmosphere by oxidation of elemental mercury and is directly emitted by anthropogenic activities. We use the GEOS-Chem global chemical transport model with gaseous oxidation driven by Br atoms to quantify how surface deposition of Hg(II) is influenced by Hg(II) production at different atmospheric heights. We tag Hg(II) chemically produced in the lower (surface–750 hPa), middle (750–400 hPa), and upper troposphere (400 hPa–tropopause), in the stratosphere, as well as directly emitted Hg(II). We evaluate our 2-year simulation (2013–2014) against observations of Hg(II) wet deposition as well as surface and free-tropospheric observations of Hg(II), finding reasonable agreement. We find that Hg(II) produced in the upper and middle troposphere constitutes 91 % of the tropospheric mass of Hg(II) and 91 % of the annual Hg(II) wet deposition flux. This large global influence from the upper and middle troposphere is the result of strong chemical production coupled with a long lifetime of Hg(II) in these regions. Annually, 77–84 % of surface-level Hg(II) over the western US, South America, South Africa, and Australia is produced in the upper and middle troposphere, whereas 26–66 % of surface Hg(II) over the eastern US, Europe, and East Asia, and South Asia is directly emitted. The influence of directly emitted Hg(II) near emission sources is likely higher but cannot be quantified by our coarse-resolution global model (2° latitude  ×  2.5° longitude). Over the oceans, 72 % of surface Hg(II) is produced in the lower troposphere because of higher Br concentrations in the marine boundary layer. The global contribution of the upper and middle troposphere to the Hg(II) dry deposition flux is 52 %. It is lower compared to the contribution to wet deposition because dry deposition of Hg(II) produced aloft requires its entrainment into the boundary layer, while rain can scavenge Hg(II) from higher altitudes more readily. We find that 55 % of the spatial variation of Hg wet deposition flux observed at the Mercury Deposition Network sites is explained by the combined variation of precipitation and Hg(II) produced in the upper and middle troposphere. Our simulation points to a large role of the dry subtropical subsidence regions. Hg(II) present in these regions accounts for 74 % of Hg(II) at 500 hPa over the continental US and more than 60 % of the surface Hg(II) over high-altitude areas of the western US. Globally, it accounts for 78 % of the tropospheric Hg(II) mass and 61 % of the total Hg(II) deposition. During the Nitrogen, Oxidants, Mercury, and Aerosol Distributions, Sources, and Sinks (NOMADSS) aircraft campaign, the contribution of Hg(II) from the dry subtropical regions was found to be 75 % when measured Hg(II) exceeded 250 pg m−3. Hg(II) produced in the upper and middle troposphere subsides in the anticyclones, where the dry conditions inhibit the loss of Hg(II). Our results highlight the importance the subtropical anticyclones as the primary conduits for the production and export of Hg(II) to the global atmosphere.

Wet Deposition Fluxes of Nitrate and Ammonium at a Rural Agricultural Site in north India

2021 ◽  
Author(s):  
Sudesh Yadav ◽  
Umesh Kulshrestha
Keyword(s):  
Wet Deposition ◽  
Major Ions ◽  
Monsoon Season ◽  
North India ◽  
Reactive Nitrogen ◽  
Deposition Flux ◽  
Deposition Fluxes ◽  
Average Value ◽  
Wet Deposition Flux ◽  
Agricultural Site

&lt;p&gt;The chemical composition of rainwater is an indicator of the air quality and sources of influence. In this study, pH and ionic concentrations were measured in rain samples collected during monsoon season of 2018 at a rural agricultural site located in northern part of India. Wet deposition fluxes of reactive nitrogen species NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; over NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; were calculated to estimate their annual deposition. The pH of samples varied between 5.2 and 6.14, with an average value of 5.72 which is in alkaline range considering 5.6 as the neutral pH of cloud water with atmospheric CO&lt;sub&gt;2&lt;/sub&gt; equilibrium. These relatively high pH values indicate the neutralisation of acidity in precipitation. Samples were analysed for their cationic and anionic content using ion chromatography. The results showed that NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; concentrations were higher than NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;- &lt;/sup&gt;with the VWM concentrations of 187.23 &amp;#956;eql&lt;sup&gt;-1&lt;/sup&gt; and 26.79 &amp;#956;eql&lt;sup&gt;-1&lt;/sup&gt; respectively. Furthermore, wet deposition flux of NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;-N was calculated as 4.25 kg ha&lt;sup&gt;-1&lt;/sup&gt; yr&lt;sup&gt;-1&lt;/sup&gt; while that of NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;-N was as 2.10 kg ha&lt;sup&gt;-1&lt;/sup&gt; yr&lt;sup&gt;-1&lt;/sup&gt;. VWM concentrations of major ions decreased in the following order NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; &gt; Ca&lt;sup&gt;2+&lt;/sup&gt; &gt; SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt; &gt; NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; &gt; K&lt;sup&gt;+&lt;/sup&gt; &gt; Cl&lt;sup&gt;-&lt;/sup&gt; &gt; Na&lt;sup&gt;+&lt;/sup&gt; &gt; Mg&lt;sup&gt;2+&lt;/sup&gt;. In this study, relatively high NH&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; concentrations in rainwater can be attributed to nearby agricultural activities, excreta and biomass burning.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Keywords:&lt;/strong&gt; Rainwater, Neutralisation, VWM concentration, Agricultural site, Reactive Nitrogen.&lt;/p&gt;

scholarly journals Total atmospheric mercury deposition in forested areas in South Korea

2016 ◽  
Vol 16 (12) ◽  
pp. 7653-7662 ◽  
Author(s):  
Jin-Su Han ◽  
Yong-Seok Seo ◽  
Moon-Kyung Kim ◽  
Thomas M. Holsen ◽  
Seung-Muk Yi
Keyword(s):  
South Korea ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Deciduous Forest ◽  
Atmospheric Mercury ◽  
Deposition Flux ◽  
Mercury Deposition ◽  
Temperate Deciduous Forest ◽  
Deposition Fluxes ◽  
Forested Areas

Abstract. In this study, mercury (Hg) was sampled weekly in dry and wet deposition and throughfall and monthly in litterfall, and as it was volatilized from soil from August 2008 to February 2010 to identify the factors influencing the amount of atmospheric Hg deposited to forested areas in a temperate deciduous forest in South Korea. For this location there was no significant correlation between the estimated monthly dry deposition flux (litterfall + throughfall – wet deposition) (6.7 µg m−2 yr−1) and directly measured dry deposition (9.9 µg m−2 yr−1) likely due primarily to Hg losses from the litterfall collector. Dry deposition fluxes in cold seasons (fall and winter) were lower than in warmer seasons (spring and summer). The volume-weighted mean (VWM) Hg concentrations in both precipitation and throughfall were highest in winter, likely due to increased scavenging by snow events. Since South Korea experiences abundant rainfall in summer, VWM Hg concentrations in summer were lower than in other seasons. Litterfall fluxes were highest in the late fall to early winter, when leaves were dropped from the trees (September to November). The cumulative annual Hg emission flux from soil was 6.8 µg m−2 yr−1. Based on these data, the yearly deposition fluxes of Hg calculated using two input approaches (wet deposition + dry deposition or throughfall + litterfall) were 6.8 and 3.6 µg m−2 yr−1, respectively. This is the first reported study which measured the amount of atmospheric Hg deposited to forested areas in South Korea, and thus our results provide useful information to compare against data related to Hg fate and transport in this part of the world.

scholarly journals Surface deposition of oxidized mercury dominated by production in the upper and middle troposphere

2017 ◽  
Author(s):  
Viral Shah ◽  
Lyatt Jaeglé
Keyword(s):  
Boundary Layer ◽  
Dry Deposition ◽  
Wet Deposition ◽  
Lower Troposphere ◽  
The United States ◽  
Atmospheric Mercury ◽  
Deposition Flux ◽  
Surface Deposition ◽  
Middle Troposphere ◽  
Wet Deposition Flux

Abstract. Oxidized mercury (Hg(II)) is chemically produced in the atmosphere by oxidation of elemental mercury and is directly emitted by anthropogenic activities. We use the GEOS-Chem global chemical transport model, with gaseous oxidation driven by Br atoms, to quantify how surface deposition of Hg(II) is influenced by Hg(II) production at different atmospheric heights. We tag Hg(II) chemically produced in the lower (surface–750 hPa), middle (750–400 hPa) and upper troposphere (400 hPa–tropopause), in the stratosphere, as well as directly emitted Hg(II). A two-year simulation (2013–2014) reproduces the spatial distribution and seasonal cycle of Hg(II) surface concentrations and Hg wet deposition observed at the Atmospheric Mercury Network (AMNet) and the Mercury Deposition Network (MDN) stations over the United States to within 21 %, but displays a 46 % underestimate of wet deposition observed at the European Monitoring and Evaluation Programme (EMEP) stations. We find that Hg(II) produced in the upper and middle troposphere constitutes 91 % of the tropospheric mass of Hg(II) and 91 % of the annual Hg(II) wet deposition flux. This large global influence from the upper and middle troposphere is the result of strong chemical production coupled with a long lifetime of Hg(II) in these regions. Annually, 77–84 % of surface level Hg(II) over the western U.S., South America, South Africa, and Australia is produced in the upper and middle troposphere, whereas 26–66 % of surface Hg(II) over the eastern U.S., Europe, East Asia, and South Asia is directly emitted. Over the oceans, 72 % of surface Hg(II) is produced in the lower troposphere, because of higher Br concentrations in the marine boundary layer. The global contribution of the upper and middle troposphere to the Hg(II) dry deposition flux is 52 %. It is lower compared to the contribution to wet deposition because dry deposition of Hg(II) produced aloft requires its entrainment into the boundary layer, while rain can scavenge Hg(II) from higher altitudes more readily. We find that 55 % of the spatial variation of Hg wet deposition flux observed at the MDN sites is explained by the combined variation of precipitation and Hg(II) produced in the upper and middle troposphere. Our simulation points to a large role of Hg(II) present in the dry subtropical subsidence regions, which account for 74 % of Hg(II) at 500 hPa over the continental U.S., and more than 60 % of the surface Hg(II) over high-altitude areas of the western U.S. During the Nitrogen, Oxidants, Mercury, and Aerosol Distributions, Sources, and Sinks (NOMADSS) aircraft campaign, the contribution of these dry regions was found to be 75 % when measured Hg(II) exceeded 250 pg m−3. Our results highlight the importance of the upper and middle troposphere as key regions for Hg(II) production and of the subtropical anticyclones as the primary conduits for the production and export of Hg(II) to the global atmosphere.

scholarly journals Characteristics of atmospheric mercury deposition and size-fractionated particulate mercury in urban Nanjing, China

2014 ◽  
Vol 14 (5) ◽  
pp. 2233-2244 ◽  
Author(s):  
J. Zhu ◽  
T. Wang ◽  
R. Talbot ◽  
H. Mao ◽  
X. Yang ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Fine Particles ◽  
Unit Area ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
Deposition Flux ◽  
Coarse Particles ◽  
Mercury Deposition ◽  
Particulate Mercury

Abstract. A comprehensive measurement study of mercury wet deposition and size-fractionated particulate mercury (HgP) concurrent with meteorological variables was conducted from June 2011 to February 2012 to evaluate the characteristics of mercury deposition and particulate mercury in urban Nanjing, China. The volume-weighted mean (VWM) concentration of mercury in rainwater was 52.9 ng L−1 with a range of 46.3–63.6 ng L−1. The wet deposition per unit area was averaged 56.5 μg m−2 over 9 months, which was lower than that in most Chinese cities, but much higher than annual deposition in urban North America and Japan. The wet deposition flux exhibited obvious seasonal variation strongly linked with the amount of precipitation. Wet deposition in summer contributed more than 80% to the total amount. A part of contribution to wet deposition of mercury from anthropogenic sources was evidenced by the association between wet deposition and sulfates, as well as nitrates in rainwater. The ions correlated most significantly with mercury were formate, calcium, and potassium, which suggested that natural sources including vegetation and resuspended soil should be considered as an important factor to affect the wet deposition of mercury in Nanjing. The average HgP concentration was 1.10 ± 0.57 ng m−3. A distinct seasonal distribution of HgP concentrations was found to be higher in winter as a result of an increase in the PM10 concentration. Overall, more than half of the HgP existed in the particle size range less than 2.1 μm. The highest concentration of HgP in coarse particles was observed in summer, while HgP in fine particles dominated in fall and winter. The size distribution of averaged mercury content in particulates was bimodal, with two peaks in the bins of < 0.7 μm and 4.7–5.8 μm. Dry deposition per unit area of HgP was estimated to be 47.2 μg m−2 using meteorological conditions and a size-resolved particle dry deposition model. This was 16.5% less than mercury wet deposition. Compared to HgP in fine particles, HgP in coarse particles contributed more to the total dry deposition due to higher deposition velocities. Negative correlation between precipitation and the HgP concentration reflected the effect of scavenging of HgP by precipitation.

scholarly journals Wet and dry deposition of mineral dust particles in Japan: factors related to temporal variation and spatial distribution

2013 ◽  
Vol 13 (8) ◽  
pp. 21801-21835
Author(s):  
K. Osada ◽  
S. Ura ◽  
M. Kagawa ◽  
M. Mikami ◽  
T. Y. Tanaka ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Mineral Dust ◽  
Temporal Variations ◽  
Dust Particles ◽  
Insoluble Residue ◽  
Spatial Distributions ◽  
Dust Deposition ◽  
Deposition Fluxes ◽  
Deposition Amount

Abstract. Data of temporal variations and spatial distributions of mineral dust deposition fluxes are very limited in terms of duration, location, and processes of deposition. To ascertain temporal variations and spatial distributions of mineral dust deposition by wet and dry processes, weekly deposition samples were obtained at Sapporo, Toyama, Nagoya, Tottori, Fukuoka, and Cape Hedo (Okinawa) in Japan during October 2008–December 2010 using automatic wet and dry separating samplers. Mineral dust weights in water-insoluble residue were estimated from Fe contents measured using an X-ray fluorescence analyzer. For wet deposition, highest and lowest annual dust fluxes were found at Toyama (9.6 g m−2 yr−1) and at Cape Hedo (1.7 g m−2 yr−1) as average values in 2009 and 2010. Higher wet deposition fluxes were observed at Toyama and Tottori, where frequent precipitation (>60% days per month) was observed during dusty seasons. For dry deposition among Toyama, Tottori, Fukuoka, and Cape Hedo, the highest and lowest annual dust fluxes were found respectively at Fukuoka (5.2 g m−2 yr−1) and at Cape Hedo (2.0 g m−2 yr−1) as average values in 2009 and 2010. Although the seasonal tendency of the monthly dry deposition amount roughly resembled that of monthly days of Kosa dust events, the monthly amount of dry deposition was not proportional to monthly days of the events. Comparison of dry deposition fluxes with vertical distribution of dust particles deduced from Lidar data and coarse particle concentrations suggested that the maximum dust layer height or thickness is an important factor for controlling the dry deposition amount after long-range transport of dust particles. Size distributions of refractory dust particles were obtained using four-stage filtration: >20, >10, >5, and >1 μm diameter. Weight fractions of the sum of >20 μm and 10–20 μm (giant fraction) were higher than 50% for most of the event samples. Irrespective of the deposition type, the giant dust fractions were decreasing generally with increasing distance from the source area, suggesting the selective depletion of larger giant particles during atmospheric transport. Because giant dust particles are an important mass fraction of dust accumulation, especially in the north Pacific where is known as a high-nutrient, low-chlorophyll (HNLC) region, the transport height of giant dust particles is an important factor for studying dust budgets in the atmosphere and their role in biogeochemical cycles.

scholarly journals Impacts of Anthropogenic Emissions and Meteorological Variation on Hg Wet Deposition in Chongming, China

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1301
Author(s):  
Yi Tang ◽  
Qingru Wu ◽  
Wei Gao ◽  
Shuxiao Wang ◽  
Zhijian Li ◽  
...  
Keyword(s):  
Wet Deposition ◽  
Warm Season ◽  
Meteorological Condition ◽  
Anthropogenic Emissions ◽  
Deposition Flux ◽  
Wet Deposition Flux ◽  
Meteorological Variation ◽  
Global Concern ◽  
The Impact

Mercury (Hg) is a ubiquitous environmental toxicant that has caused global concern due to its persistence and bioaccumulation in the environment. Wet deposition is a crucial Hg input for both terrestrial and aquatic environments and is a significant indicator for evaluating the effectiveness of anthropogenic Hg control. Rainwater samples were collected from May 2014 to October 2018 in Chongming Island to understand the multi-year Hg wet deposition characteristics. The annual Hg wet deposition flux ranged from 2.6 to 9.8 μg m−2 yr−1 (mean: 4.9 μg m−2 yr−1). Hg wet deposition flux in Chongming was comparable to the observations at temperate and subtropical background sites (2.0–10.2 μg m−2 yr−1) in the northern hemisphere. Hg wet deposition flux decreased from 8.6 μg m−2 yr−1 in 2014–2015 to 3.8 μg m−2 yr−1 in 2016 and was attributed to a decrease in the volume-weighted mean (VWM) Hg concentration (−4.1 ng L−1 yr−1). The reduced VWM Hg was explained by the decreasing atmospheric Hg and anthropogenic emissions reductions. The annual Hg wet deposition flux further decreased from 3.8 μg m−2 in 2016 to 2.6 μg m−2 in 2018. The reduction of warm season (April–September) rainfall amounts (356–845 mm) mainly contributed to the Hg wet deposition flux reduction during 2016–2018. The multi-year monitoring results suggest that long-term measurements are necessary when using wet deposition as an indicator to reflect the impact of anthropogenic efforts on mercury pollution control and meteorological condition variations.

Dry deposition fluxes of ambient particulate heavy metals in a small city, Korea

2002 ◽  
Vol 36 (35) ◽  
pp. 5449-5458 ◽  
Author(s):  
Hui-Jung Yun ◽  
Seung-Muk Yi ◽  
Y.P. Kim
Keyword(s):  
Heavy Metals ◽  
Dry Deposition ◽  
Small City ◽  
Deposition Fluxes

scholarly journals Elemental carbon in snow at Changbai Mountain, northeastern China: concentrations, scavenging ratios, and dry deposition velocities

2014 ◽  
Vol 14 (2) ◽  
pp. 629-640 ◽  
Author(s):  
Z. W. Wang ◽  
J. C. Gallet ◽  
C. A. Pedersen ◽  
X. S. Zhang ◽  
J. Ström ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Radiative Forcing ◽  
Elemental Carbon ◽  
Northeastern China ◽  
Snow Surface ◽  
Deposition Fluxes ◽  
The Mean ◽  
Deposition Processes ◽  
Scavenging Ratio

Abstract. Light-absorbing aerosol – particularly elemental carbon (EC) – while mixed with snow and ice is an important climate driver from the enhanced absorption of solar radiation. Currently, considerable efforts are being made to estimate its radiative forcing on a global scale, but several uncertainties remain, particularly those regarding its deposition processes. In this study, concurrent measurements of EC in air and snow are performed for three years (2009–2012) at Changbai station, northeastern China. The scavenging ratio and the wet- and dry-deposition fluxes of EC over the snow surface are estimated. The mean EC concentration in the surface snow is 1000 ± 1500 ng g−1, ranging from 7 to 7640 ng g−1. The mean value of the scavenging ratio of EC by snow is 140 ± 100, with a median value of 150, which is smaller than that reported in Arctic areas. A non-rimed snow process is a significant factor in interpreting differences with Arctic areas. Wet-deposition fluxes of EC are estimated to be 0.47 ± 0.37 μg cm−2 month−1 on average over the three snow seasons studied. Dry deposition is more than five times higher, with an average of 2.65 ± 1.93 μg cm−2 month−1; however, only winter period estimation is possible (December–February). During winter in Changbai, 87% of EC in snow is estimated to be due to dry deposition, with a mean dry deposition velocity of 6.44 × 10−3 m s−1 and median of 8.14 × 10−3 m s−1. Finally, the calculation of the radiative effect shows that 500 ng g−1 of dry-deposited EC to a snow surface absorbs three times more incoming solar energy than the same mass mixed in the snow through wet deposition. Deposition processes of an EC-containing snow surface are, therefore, crucial to estimate its radiative forcing better, particularly in northeastern China, where local emission strongly influences the level and gradient of EC in the snowpack, and snow-covered areas are cold and dry due to the atmospheric general circulation. Furthermore, this study builds on the knowledge to characterize the conditions in the snow-laden Chinese rural areas better as well as to constrain transport of EC to the Arctic better.

scholarly journals How are NH<sub>3</sub> dry deposition estimates affected by combining the LOTOS-EUROS model with IASI-NH<sub>3</sub> satellite observations?

2018 ◽  
Author(s):  
Shelley C. van der Graaf ◽  
Enrico Dammers ◽  
Martijn Schaap ◽  
Jan Willem Erisman
Keyword(s):  
Dry Deposition ◽  
Transport Model ◽  
Atmospheric Transport ◽  
Deposition Velocity ◽  
Deposition Flux ◽  
Deposition Fluxes ◽  
Po Valley ◽  
Atmospheric Remote Sensing ◽  
Spatial Coverage ◽  
Recent Developments

Abstract. Atmospheric levels of reactive nitrogen have substantially increased during the last century resulting in increased nitrogen deposition to ecosystems, causing harmful effects such as soil acidification, reduction in plant biodiversity and eutrophication in lakes and the ocean. Recent developments in the use of atmospheric remote sensing enabled us to resolve concentration fields of NH3 with larger spatial coverage and these observations may be used to improve the quantification of NH3 deposition. In this paper we use a relatively simple, data-driven method to derive dry deposition fluxes and surface concentrations of NH3 for Europe and for the Netherlands. The aim of this paper is to determine for the applicability and the limitations of this method for NH3 using space-born observations of the Infrared Atmospheric Sounding Interferometer (IASI) and the LOTOS-EUROS atmospheric transport model. The original modelled dry NH3 deposition flux from LOTOS-EUROS and the flux inferred from IASI are compared to indicate areas with large discrepancies between the two and where potential model improvements are needed. The largest differences in derived dry deposition fluxes occur in large parts of Central Europe, where the satellite-observed NH3 concentrations are higher than the modelled ones, and in Switzerland, northern Italy (Po Valley) and southern Turkey, where the modelled NH3 concentrations are higher than the satellite-observed ones. A sensitivity analysis of 8 model input parameters important for NH3 dry deposition modelling showed that the IASI-derived dry NH3 deposition fluxes may vary from ~ 20 % up to ~ 50 % throughout Europe. Variations in the dry deposition velocity used for NH3 led to the largest deviations in the IASI-derived dry NH3 deposition flux and should be focused on in the future. A comparison of NH3 surface concentrations with in-situ measurements of several established networks (EMEP, MAN and LML) showed no significant, or consistent improvement in the IASI-derived NH3 surface concentrations compared to the originally modelled NH3 surface concentrations from LOTOS-EUROS. It is concluded that the IASI-derived NH3 deposition fluxes do not show strong improvements compared to modelled NH3 deposition fluxes and there is future need for better, more robust, methods to derive NH3 dry deposition fluxes.

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