scholarly journals Evaluation of size segregation of elemental carbon emission in Europe: influence on atmospheric long-range transportation

2015 ◽  
Vol 15 (21) ◽  
pp. 31053-31087 ◽  
Author(s):  
Y. Chen ◽  
Y. F. Cheng ◽  
S. Nordmann ◽  
W. Birmili ◽  
H. A. C. Denier van der Gon ◽  
...  

Abstract. Elemental Carbon (EC) has significant impact on human health and climate change. In order to evaluate the size segregation of EC emission and investigation of its influence on atmospheric transport processes in Europe, we used the fully coupled online Weather Research and Forecasting/Chemistry model (WRF-Chem) at a resolution of 2 km focusing on a region in Germany, in conjunction with a high-resolution EC emission inventory. The ground meteorology conditions, vertical structure and wind pattern were well reproduced by the model. The simulations of particle number/mass size distributions were evaluated by observations taken at the central European background site Melpitz. The fine mode aerosol was reasonably well simulated, but the coarse mode was substantially overestimated by the model. We found that it was mainly due to the nearby point source plume emitting a high amount of EC in the coarse mode. The comparisons between simulated EC and Multi-angle Absorption Photometers (MAAP) measurements at Melpitz, Leipzig-TROPOS and Bösel indicated that coarse mode EC (ECc) emission in the nearby point sources might be overestimated by a factor of 2–10. The emission fraction of EC in coarse mode was overestimated by about 10–30 % for Russian and 5–10 % for Eastern Europe (e.g.: Poland and Belarus), respectively. This overestimation in ECc emission fraction makes EC particles having less opportunity to accumulate in the atmosphere and participate to the long range transport, due to the shorter lifetime of coarse mode aerosol. The deposition concept model showed that the transported EC mass from Warsaw and Moskva to Melpitz may be reduced by 25–35 and 25–55 % respectively, due to the overestimation of ECc emission fraction. This may partly explain the underestimation of EC concentrations for Germany under eastern wind pattern in some other modelling research.

2016 ◽  
Vol 16 (3) ◽  
pp. 1823-1835 ◽  
Author(s):  
Ying Chen ◽  
Ya-Fang Cheng ◽  
Stephan Nordmann ◽  
Wolfram Birmili ◽  
Hugo A. C. Denier van der Gon ◽  
...  

Abstract. Elemental Carbon (EC) has a significant impact on human health and climate change. In order to evaluate the size segregation of EC emission in the EUCAARI inventory and investigate its influence on the simulation of EC long-range transportation in Europe, we used the fully coupled online Weather Research and Forecasting/Chemistry model (WRF-Chem) at a resolution of 2 km focusing on a region in Germany, in conjunction with a high-resolution EC emission inventory. The ground meteorology conditions, vertical structure and wind pattern were well reproduced by the model. The simulations of particle number and/or mass size distributions were evaluated with observations at the central European background site Melpitz. The fine mode particle concentration was reasonably well simulated, but the coarse mode was substantially overestimated by the model mainly due to the plume with high EC concentration in coarse mode emitted by a nearby point source. The comparisons between simulated EC and Multi-angle Absorption Photometers (MAAP) measurements at Melpitz, Leipzig-TROPOS and Bösel indicated that the coarse mode EC (ECc) emitted from the nearby point sources might be overestimated by a factor of 2–10. The fraction of ECc was overestimated in the emission inventory by about 10–30 % for Russia and 5–10 % for Eastern Europe (e.g., Poland and Belarus). This incorrect size-dependent EC emission results in a shorter atmospheric life time of EC particles and inhibits the long-range transport of EC. A case study showed that this effect caused an underestimation of 20–40 % in the EC mass concentration in Germany under eastern wind pattern.


2007 ◽  
Vol 7 (14) ◽  
pp. 3969-3987 ◽  
Author(s):  
M. G. Lawrence ◽  
T. M. Butler ◽  
J. Steinkamp ◽  
B. R. Gurjar ◽  
J. Lelieveld

Abstract. Megacities and other major population centers represent large, concentrated sources of anthropogenic pollutants to the atmosphere, with consequences for both local air quality and for regional and global atmospheric chemistry. The tradeoffs between the regional buildup of pollutants near their sources versus long-range export depend on meteorological characteristics which vary as a function of geographical location and season. Both horizontal and vertical transport contribute to pollutant export, and the overall degree of export is strongly governed by the lifetimes of pollutants. We provide a first quantification of these tradeoffs and the main factors influencing them in terms of "regional pollution potentials", metrics based on simulations of representative tracers using the 3-D global model MATCH (Model of Atmospheric Transport and Chemistry). The tracers have three different lifetimes (1, 10, and 100 days) and are emitted from 36 continental large point sources. Several key features of the export characteristics emerge. For instance, long-range near-surface pollutant export is generally strongest in the middle and high latitudes, especially for source locations in Eurasia, for which 17–34% of a tracer with a 10-day lifetime is exported beyond 1000 km and still remains below 1 km altitude. On the other hand, pollutant export to the upper troposphere is greatest in the tropics, due to transport by deep convection, and for six source locations, more than 50% of the total mass of the 10-day lifetime tracer is found above 5 km altitude. Furthermore, not only are there order of magnitude interregional differences, such as between low and high latitudes, but also often substantial intraregional differences, which we discuss in light of the regional meteorological characteristics. We also contrast the roles of horizontal dilution and vertical mixing in reducing the pollution buildup in the regions including and surrounding the sources. For some regions such as Eurasia, dilution due to long-range horizontal transport governs the local and regional pollution buildup; however, on a global basis, differences in vertical mixing are dominant in determining the pollution buildup both around and further downwind of the source locations.


1995 ◽  
Vol 160-161 ◽  
pp. 323-335 ◽  
Author(s):  
J. Ford ◽  
D. Landers ◽  
D. Kugler ◽  
B. Lasorsa ◽  
S. Allen-Gil ◽  
...  

1997 ◽  
Vol 5 (2) ◽  
pp. 99-120 ◽  
Author(s):  
T A Jackson

Literature on the long-range atmospheric transport of both anthropogenic and naturally occurring mercury (Hg) to terrestrial and aquatic ecosystems was reviewed for the purpose of assessing the quantitative importance and environmental significance of the anthropogenic emissions. The weight of evidence, comprising many different kinds of data that corroborate each other independently, supports the following conclusions. (i) Approximately 5000 t of anthropogenic Hg are introduced into the atmosphere every year, both by direct emission from sources of pollution and by reemission of previously deposited Hg from diffuse secondary sources in the environment. The primary emissions ( 4000 t) result from various human activities, especially the combustion of fossil fuels (notably coal) and solid wastes. Natural emissions amount to about 2000 t/year. (ii) Although some of the annual anthropogenic Hg output (about half the quantity emitted by primary sources) is deposited near its point sources, the rest (a total of 3000 t) is subject to transport over great distances by atmospheric circulation, resulting in measurable contamination of terrestrial and aquatic environments and organisms up to several thousand kilometers from the points of origin. Indeed, a number of remote ecosystems receive most of their Hg input from the atmosphere. (iii) The available evidence supports the generally accepted conclusion that the Hg enrichment commonly seen in the uppermost horizons of sediment cores from remote lakes is due primarily to contamination by airborne anthropogenic Hg in the recent past, rather than postdepositional redistribution of Hg. Although postdepositional alteration may result in detectable remobilization of sedimentary Hg, its effects on total Hg profiles in lake sediment cores have been found, thus far, to be negligible. (iv) Atmospheric transport of anthropogenic Hg to aquatic and terrestrial ecosystems is a cause for concern, as the Hg is accumulating, to a greater or lesser extent, in organisms (e.g., fish in remote lakes). Moreover, the Hg is associated with, and interacts with, other by-products of fossil fuel combustion, including the strong acids responsible for acid precipitation. The acids aggravate the effects of Hg pollution by furthering the accumulation of methyl Hg in fish inhabiting ill-buffered lakes. Contamination of the atmosphere with Hg and associated pollutants is a serious international problem that calls for reduction or elimination of emissions.


2006 ◽  
Vol 6 (6) ◽  
pp. 13323-13366 ◽  
Author(s):  
M. G. Lawrence ◽  
T. M. Butler ◽  
J. Steinkamp ◽  
B. R. Gurjar ◽  
J. Lelieveld

Abstract. Megacities and other major population centers represent important, concentrated sources of anthropogenic pollutants to the atmosphere, with consequences for both local air quality and for regional and global atmospheric chemistry. The tradeoff between the regional buildup of pollutants near their sources versus long-range export depends on meteorological characteristics which vary as a function of geographical location and season. Both horizontal and vertical transport contribute to pollutant export, and the overall degree of export is strongly governed by the chemical lifetimes of pollutants. We provide a first quantification of this tradeoff and the main factors influencing it in terms of "regional pollution potentials", metrics based on simulations of artificial, representative tracers using the 3-D global model MATCH (Model of Atmospheric Transport and Chemistry). The tracers have three different lifetimes (1, 10, and 100 days) and are emitted from 36 continental point sources representing the 30 current largest cities around the world plus 6 additional major population centers. Several key features of the export characteristics emerge: 1) long-range near-surface pollutant export is generally strongest in the middle and high latitudes, especially for source locations in Eurasia; 2) on the other hand, pollutant export to the upper troposphere is greatest in the tropics, due to transport by deep convection; 3) not only are there order of magnitude interregional differences, such as between low and high latitudes, but also often substantial intraregional differences, for instance between the sources in western India and Pakistan versus eastern India and Bangladesh; 4) contrary to what one might initially expect, efficient long-range export does not necessarily correspond with a more significant dilution of pollutants near their source, rather the amount of low-level, long-range export (e.g., below 1 km and beyond 1000 km) is well-correlated with exceedences of surface density thresholds on regional scales near the source (e.g., within ~1000 km), implying that pollutant buildup to high densities in the surface layer of the region surrounding the source location is more strongly influenced by vertical than horizontal transport.


2021 ◽  
Author(s):  
Fabian Maier ◽  
Christoph Gerbig ◽  
Ingeborg Levin ◽  
Ingrid Super ◽  
Julia Marshall ◽  
...  

Abstract. An appropriate representation of point source emissions in atmospheric transport models is very challenging. In the Stochastic Time Inverted Lagrangian Transport model (STILT), all point source emissions are typically released from the surface, meaning that the actual emission stack height plus subsequent plume rise is not considered. This can lead to erroneous predictions of trace gas concentrations, especially during nighttime when vertical atmospheric mixing is minimal. In this study we use two WRF–STILT model approaches to simulate fossil fuel CO2 (ffCO2) concentrations: (1) the standard “surface source influence (SSI)” approach, and (2) an alternative “volume source influence (VSI)” approach, where nearby point sources release CO2 according to their effective emission height profiles. The comparison with 14C-based measured ffCO2 data from two-week integrated afternoon and nighttime samples collected at Heidelberg, 30 m above ground level, shows that the root-mean-square deviation (RMSD) between modelled and measured ffCO2 is indeed almost twice as high during night (RMSD = 6.3 ppm) compared to the afternoon (RMSD = 3.7 ppm) when using the standard SSI approach. In contrast, the VSI approach leads to a much better performance at nighttime (RMSD = 3.4 ppm), which is similar to its performance during afternoon (RMSD = 3.7 ppm). Representing nearby point source emissions with the VSI approach could, thus, be a first step towards exploiting nocturnal observations in STILT. To further investigate the differences between these two approaches, we conducted a model experiment in which we simulated the ffCO2 contributions from 12 artificial power plants with typical annual emissions of one million tons of CO2 and with distances between 5 and 200 km from the Heidelberg observation site. We find that such a power plant must be more than 50 km away from the observation site in order for the mean modelled ffCO2 concentration difference between the SSI and VSI approach to fall below 0.1 ppm.


Tellus B ◽  
2011 ◽  
Vol 63 (3) ◽  
Author(s):  
Borgar Aamaas ◽  
Carl Egede Bøggild ◽  
Frode Stordal ◽  
Terje Berntsen ◽  
Kim Holmén ◽  
...  

2008 ◽  
Vol 8 (10) ◽  
pp. 2811-2832 ◽  
Author(s):  
K. Zhang ◽  
H. Wan ◽  
M. Zhang ◽  
B. Wang

Abstract. The radioactive species radon (222Rn) has long been used as a test tracer for the numerical simulation of large scale transport processes. In this study, radon transport experiments are carried out using an atmospheric GCM with a finite-difference dynamical core, the van Leer type FFSL advection algorithm, and two state-of-the-art cumulus convection parameterization schemes. Measurements of surface concentration and vertical distribution of radon collected from the literature are used as references in model evaluation. The simulated radon concentrations using both convection schemes turn out to be consistent with earlier studies with many other models. Comparison with measurements indicates that at the locations where significant seasonal variations are observed in reality, the model can reproduce both the monthly mean surface radon concentration and the annual cycle quite well. At those sites where the seasonal variation is not large, the model is able to give a correct magnitude of the annual mean. In East Asia, where radon simulations are rarely reported in the literature, detailed analysis shows that our results compare reasonably well with the observations. The most evident changes caused by the use of a different convection scheme are found in the vertical distribution of the tracer. The scheme associated with weaker upward transport gives higher radon concentration up to about 6 km above the surface, and lower values in higher altitudes. In the lower part of the atmosphere results from this scheme does not agree as well with the measurements as the other scheme. Differences from 6 km to the model top are even larger, although we are not yet able to tell which simulation is better due to the lack of observations at such high altitudes.


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