scholarly journals Future climatic drivers and their effect on PM<sub>10</sub> components in Europe and the Mediterranean Sea

2018 ◽  
Author(s):  
Arineh Cholakian ◽  
Augustin Colette ◽  
Giancarlo Ciarelli ◽  
Isabelle Coll ◽  
Matthias Beekmann

Abstract. Multiple CMIP5 future scenarios are compared to historic simulations in order to study different drivers governing air pollution: Regional climate, anthropogenic emissions and long-range transport. Climate impact study covers the period of 2031 to 2100 for future scenarios compared to 1976 to 2005 for historic simulations, and includes three RCPs (Representative concentration pathways, RCP2.6, RCP4.5 and RCP8.5). A detailed analysis of total PM10 concentrations, its changes and also that of its components is included. The individual effects of meteorological conditions on PM10 components are explored in these scenarios in an effort to pinpoint the meteorological parameter(s) governing each component. Anthropogenic emission impact study covers the period of 2046 and 2055 with CLE2050 (Current legislation emissions for 2050) anthropogenic emissions compared to CLE2010 in historic simulations covering the period of 1996 to 2005. Long-range transport is explored by changing the initial and boundary conditions in the chemistry-transport model, these scenarios cover the same period as the emission impact studies. Finally, a cumulative effects of these drivers is performed and the contribution of each driver on PM10 and its components is calculated. The results show that, regional climate causes a decrease in PM10 concentration in our scenarios, as a result of a decrease in nitrate, sulfate, ammonium and dust in most scenarios. Meanwhile, biogenic secondary organic aerosols (BSOA) shows an important increase in all scenarios. Nitrate and BSOA show a strong dependence to temperature, while sulfates are dependent to relative humidity. A cumulative look at all drivers shows that anthropogenic emission changes overshadow changes caused by climate and long-range transport for most components except for dust, for which long-range transport changes seem to be more influential.

2019 ◽  
Vol 19 (7) ◽  
pp. 4459-4484 ◽  
Author(s):  
Arineh Cholakian ◽  
Augustin Colette ◽  
Isabelle Coll ◽  
Giancarlo Ciarelli ◽  
Matthias Beekmann

Abstract. Multiple CMIP5 (Coupled Model Intercomparison Project phase 5) future scenarios run with the CHIMERE chemistry transport model (CTM) are compared to historic simulations in order to study some of the drivers governing air pollution. Here, the focus is on regional climate, anthropogenic emissions and long-range transport. Two major subdomains are explored – the European region and the Mediterranean Basin – with both areas showing high sensitivity to climate change. The Mediterranean area is explored in the context of the ChArMEx (the Chemistry Aerosol Mediterranean Experiment) project, which examines the current and future meteorological and chemical conditions of the Mediterranean area. This climate impact study covers the period from 2031 to 2100 and considers possible future scenarios in comparison with 1976 to 2005 historic simulations using three Representative Concentration Pathways (RCPs; RCP2.6, RCP4.5 and RCP8.5). A detailed analysis of total PM10 (particulate matter with a diameter smaller that 10 µm) concentrations is carried out, including the evolution of PM10 and changes to its composition. The individual effects of meteorological conditions on PM10 components are explored in these scenarios in an effort to pinpoint the meteorological parameter(s) governing each component. The anthropogenic emission impact study covers the period from 2046 to 2055 using current legislation (CLE) and maximum feasible reduction (MFR) anthropogenic emissions for the year 2050 compared with historic simulations covering the period from 1996 to 2005 and utilizing CLE2010 emissions data. Long-range transport is explored by changing the boundary conditions in the chemistry transport model over the same period as the emission impact studies. Finally, a cumulative effect analysis of these drivers is performed, and the impact of each driver on PM10 and its components is estimated. The results show that regional climate change causes a decrease in the PM10 concentrations in our scenarios (in both the European and Mediterranean subdomains), as a result of a decrease in nitrate, sulfate, ammonium and dust atmospheric concentrations in most scenarios. On the contrary, BSOA (biogenic secondary organic aerosol) displays an important increase in all scenarios, showing more pronounced concentrations for the European subdomain compared with the Mediterranean region. Regarding the relationship of different meteorological parameters to concentrations of different species, nitrate and BSOA show a strong temperature dependence, whereas sulfate is most strongly correlated with relative humidity. The temperature-dependent behavior of BSOA changes when looking at the Mediterranean subdomain, where it displays more dependence on wind speed, due to the transported nature of BSOA existing in this subdomain. A cumulative look at all drivers shows that anthropogenic emission changes overshadow changes caused by climate and long-range transport for both of the subdomains explored, with the exception of dust particles for which long-range transport changes are more influential, especially in the Mediterranean Basin. For certain species (such as sulfates and BSOA), in most of the subdomains explored, the changes caused by anthropogenic emissions are (to a certain extent) reduced by the boundary conditions and regional climate changes.


Author(s):  
Hervé Petetin ◽  
Bastien Sauvage ◽  
Mark Parrington ◽  
Hannah Clark ◽  
Alain Fontaine ◽  
...  

<p><strong>Abstract.</strong> This study investigates the role of biomass burning and long-range transport in the anomalies of carbon monoxide (CO) regularly observed along the tropospheric vertical profiles measured in the framework of IAGOS. Considering the high interannual variability of biomass burning emissions and the episodic nature of pollution long-range transport, one strength of this study is the amount of data taken into account, namely 30,000 vertical profiles at 9 clusters of airports in Europe, North America, Asia, India and southern Africa over the period 2002&amp;ndash;2017. </p> <p> As a preliminary, a brief overview of the spatio-temporal variability, latitudinal distribution, interannual variability and trends of biomass burning CO emissions from 14 regions is provided. The distribution of CO mixing ratios at different levels of the troposphere is also provided based on the entire IAGOS database (125 million CO observations). </p> <p> This study focuses on the free troposphere (altitudes above 2<span class="thinspace"></span>km) where the long-range transport of pollution is favoured. Anomalies at a given airport cluster are here defined as departures from the local seasonally-averaged climatological vertical profile. The intensity of these anomalies varies significantly depending on the airport, with maximum (minimum) CO anomalies of 110&amp;ndash;150 (48)<span class="thinspace"></span>ppbv in Asia (Europe). Looking at the seasonal variation of the frequency of occurrence, the 25<span class="thinspace"></span>% strongest CO anomalies appears reasonably well distributed along the year, in contrast to the 5<span class="thinspace"></span>% or 1<span class="thinspace"></span>% strongest anomalies that exhibit a strong seasonality with for instance more frequent anomalies during summertime in northern United-States, during winter/spring in Japan, during spring in South-east China, during the non-monsoon seasons in south-east Asia and south India, and during summer/fall at Windhoek, Namibia. Depending on the location, these strong anomalies are observed in different parts of the free troposphere. </p> <p> In order to investigate the role of biomass burning emissions in these anomalies, we used the SOFT-IO v1.0 IAGOS added-value products that consist of FLEXPART 20-days backward simulations along all IAGOS aircraft trajectories, coupled with anthropogenic (MACCity) and biomass burning (GFAS) CO emission inventories and vertical injections. SOFT-IO estimates the contribution (in ppbv) of the recent (less than 20 days) primary worldwide CO emissions, tagged per source region. Biomass burning emissions are found to play an important role in the strongest CO anomalies observed at most airport clusters. The regional tags indicate a large contribution from boreal regions at airport clusters in Europe and North America during summer season. In both Japan and south India, the anthropogenic emissions dominate all along the year, except for the strongest summertime anomalies observed in Japan that are due to Siberian fires. The strongest CO anomalies at airport clusters located in south-east Asia are induced by fires burning during spring in south-east Asia and during fall in equatorial Asia. In southern Africa, the Windhoek airport was mainly impacted by fires in southern hemisphere Africa and South America. </p> <p> To our knowledge, no other studies have used such a large dataset of in situ vertical profiles for deriving a climatology of the impact of biomass burning versus anthropogenic emissions on the strongest CO anomalies observed in the troposphere, in combination with information on the source regions. This study therefore provides both qualitative and quantitative information for interpreting the highly variable CO vertical distribution in several regions of interest.</p>


2018 ◽  
Author(s):  
Xinyi Dong ◽  
Joshua S. Fu ◽  
Qingzhao Zhu ◽  
Jian Sun ◽  
Jiani Tan ◽  
...  

Abstract. Haze has been severely affecting the densely populated areas in China during recent years. While many of the pilot studies have been devoted to investigate the contributions from local anthropogenic emission, limited attention has been paid to the influence from long-range transport. In this study, we use simulations from 6 participating models supplied through the Task Force on Hemispheric Transport of Air Pollution Phase 2 (HTAP2) exercise to investigate the long-range transport impact of Europe and Russia/Belarussia/Ukraine on the surface air quality in East Asia, with special focus on their contributions during the haze episodes over China. The impact of 20 % anthropogenic emission perturbation from the source region is extrapolated by a factor of 5 to estimate the full impact. We find that the full impacts from EUR and RBU are 0.99 µg/m3 (3.1 %) and 1.32 µg/m3 (4.1 %) respectively during haze episodes, while the annual averaged full impacts are only 0.35 µg m3 (1.7 %) and 0.53 µg/m3 (2.6 %) respectively. By estimating the aerosol response within and above the planetary boundary layer (PBL), we find that long-range transport within the PBL contributes to 22–38 % of the total column density of aerosol response. Comparison with the HTAP Phase 1 (HTAP1) assessment reveals that from 2000 to 2010, the long-range transport from Europe to East Asia has decreased significantly by a factor of 2–10 for surface aerosol mass concentration due to the simultaneous emission reduction in source region and emission increase in the receptor region. By investigating the visibility response, we find that the long-range transport from the Europe and RBU region increases the number of haze events in China by 0.15 % and 0.11 % respectively, and the North China Plain and southeast China receives 1–3 extra haze days. This study is the first investigation into the contribution of long-range transport to haze in China with multiple model experiments.


2007 ◽  
Vol 7 (6) ◽  
pp. 1549-1564 ◽  
Author(s):  
X. Davoine ◽  
M. Bocquet

Abstract. The reconstruction of the Chernobyl accident source term has been previously carried out using core inventories, but also back and forth confrontations between model simulations and activity concentration or deposited activity measurements. The approach presented in this paper is based on inverse modelling techniques. It relies both on the activity concentration measurements and on the adjoint of a chemistry-transport model. The location of the release is assumed to be known, and one is looking for a source term available for long-range transport that depends both on time and altitude. The method relies on the maximum entropy on the mean principle and exploits source positivity. The inversion results are mainly sensitive to two tuning parameters, a mass scale and the scale of the prior errors in the inversion. To overcome this hardship, we resort to the statistical L-curve method to estimate balanced values for these two parameters. Once this is done, many of the retrieved features of the source are robust within a reasonable range of parameter values. Our results favour the acknowledged three-step scenario, with a strong initial release (26 to 27 April), followed by a weak emission period of four days (28 April–1 May) and again a release, longer but less intense than the initial one (2 May–6 May). The retrieved quantities of iodine-131, caesium-134 and caesium-137 that have been released are in good agreement with the latest reported estimations. Yet, a stronger apportionment of the total released activity is ascribed to the first period and less to the third one. Finer chronological details are obtained, such as a sequence of eruptive episodes in the first two days, likely related to the modulation of the boundary layer diurnal cycle. In addition, the first two-day release surges are found to have effectively reached an altitude up to the top of the domain (5000 m).


2011 ◽  
Vol 11 (7) ◽  
pp. 3511-3525 ◽  
Author(s):  
Y. Wang ◽  
Y. Zhang ◽  
J. Hao ◽  
M. Luo

Abstract. Both observations and a 3-D chemical transport model suggest that surface ozone over populated eastern China features a summertime trough and that the month when surface ozone peaks differs by latitude and region. Source-receptor analysis is used to quantify the contributions of background ozone and Chinese anthropogenic emissions on this variability. Annual mean background ozone over China shows a spatial gradient from 55 ppbv in the northwest to 20 ppbv in the southeast, corresponding with changes in topography and ozone lifetime. Pollution background ozone (annual mean of 12.6 ppbv) shows a minimum in the summer and maximum in the spring. On the monthly-mean basis, Chinese pollution ozone (CPO) has a peak of 20–25 ppbv in June north of the Yangtze River and in October south of it, which explains the peaks of surface ozone in these months. The summertime trough in surface ozone over eastern China can be explained by the decrease of background ozone from spring to summer (by −15 ppbv regionally averaged over eastern China). Tagged simulations suggest that long-range transport of ozone from northern mid-latitude continents (including Europe and North America) reaches a minimum in the summer, whereas ozone from Southeast Asia exhibits a maximum in the summer over eastern China. This contrast in seasonality provides clear evidence that the seasonal switch in monsoonal wind patterns plays a significant role in determining the seasonality of background ozone over China.


2014 ◽  
Vol 14 (14) ◽  
pp. 7367-7396 ◽  
Author(s):  
A. W. Zien ◽  
A. Richter ◽  
A. Hilboll ◽  
A.-M. Blechschmidt ◽  
J. P. Burrows

Abstract. Intercontinental long-range transport (LRT) events of NO2 relocate the effects of air pollution from emission regions to remote, pristine regions. We detect transported plumes in tropospheric NO2 columns measured by the GOME-2/MetOp-A instrument with a specialized algorithm and trace the plumes to their sources using the HYSPLIT Lagrangian transport model. With this algorithm we find 3808 LRT events over the ocean for the period 2007 to 2011. LRT events occur frequently in the mid-latitudes, emerging usually from coastal high-emission regions. In the free troposphere, plumes of NO2 can travel for several days to the polar oceanic atmosphere or to other continents. They travel along characteristic routes and originate from both continuous anthropogenic emission and emission events such as bush fires. Most NO2 LRT events occur during autumn and winter months, when meteorological conditions and emissions are most favorable. The evaluation of meteorological data shows that the observed NO2 LRT is often linked to cyclones passing over an emission region.


1989 ◽  
Vol 16 (3) ◽  
pp. 258-266 ◽  
Author(s):  
J. M. Byrne ◽  
E. A. McBean ◽  
K. B. Shipley ◽  
G. J. Farquhar

A statistical long-range transport of air pollutants model (UW-LRT) is utilized to simulate wet SO4 deposition in eastern North America in 1980. Model results compare favorably to an analyzed deposition field. In a comparison of the relative errors associated with four long-range transport models, the UW-LRT model demonstrates the lowest variation from recorded, analyzed deposition data. The UW-LRT model has modest data input and central processor unit time requirements. Key words: acid rain, long-range transport, spatial deposition, mathematical models.


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