Ozone and carbon monoxide budgets over the Eastern Mediterranean

Myriokefalitakis, Stelios; Daskalakis, Nikos; Fanourgakis, George S.; Voulgarakis, Apostolos; Krol, Maarten; Brugh, J. M. J. Aan de; Kanakidou, Maria

doi:10.1016/j.scitotenv.2016.04.061

Cited by 21 publications

(19 citation statements)

References 54 publications

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“…A recent review from Dayan et al [30] concluded that high summertime tropospheric ozone over the eastern Mediterranean could be attributed to frequent STE associated with tropopause folding activities [198], strong air subsidence at mid-troposphere [232], and the long-range transport of ozone-rich air masses from eastern continental Europe [154]. Myriokefalitakis et al [128] suggested that the contribution of these dynamic processes (~90%) significantly outweighed that of local precursor emissions. High summertime ozone concentrations over the UK were often associated with anti-cyclonic conditions (degrading ventilation) and the easterly flows (transporting pollution from the continental Europe to the UK) [147].…”

Section: Cyclone and Stagnationmentioning

confidence: 99%

Meteorology and Climate Influences on Tropospheric Ozone: a Review of Natural Sources, Chemistry, and Transport Patterns

2019

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Tropospheric ozone is a key air pollutant and greenhouse gas. Its fate strongly depends on meteorological conditions and therefore subject to climate change influences. Such dependences through biogenic, chemical, and dynamic processes on different spatiotemporal scales have been unraveled from observations and modeling studies. In this process-oriented review, we summarize three dominant pathways of meteorological and climatic impacts on tropospheric ozone and present their recent progress. The three pathways are influences through changes in the natural precursor emissions, the kinetics and partitioning of chemistry and deposition, and the transport of ozone and its precursors. Tropospheric ozone levels have shown significant global or regional responses to meteorological/climatic changes (e.g., changes in the Brewer-Dobson Circulation, the Hadley Circulation, and El Niño-Southern Oscillation) and can be explained through the conjunction of these pathways. Most recent model projections predict that future climate will increase surface ozone in polluted regions and decrease ozone at a global scale due to stronger ozone chemical loss. However, uncertainties in climate-ozone responses and limitations in model capability still challenge the magnitude and even the sign of such projections. We highlight the rising importance of future increase of stratosphere-troposphere exchange in modulating tropospheric ozone that may largely compensate the predicted chemical loss of tropospheric ozone burden. We also highlight that uncertainties in isoprene chemistry, biogenic emissions in changing CO 2 levels and vegetation, and interactions between ozone and vegetation may largely affect the surface ozone response to climate change. Future research and model improvements are required to fill these gaps.

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Section: Cyclone and Stagnationmentioning

confidence: 99%

Meteorology and Climate Influences on Tropospheric Ozone: a Review of Natural Sources, Chemistry, and Transport Patterns

2019

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“…The atmospheric cycles of Fe and N in TM4-ECPL have been parameterized and evaluated in Myriokefalitakis et al (2015) and Kanakidou et al (2016), respectively, while uncertainties in the computed atmospheric composition associated with different emission parameterizations have been calculated in Daskalakis et al (2015). The model's ability to reproduce distributions of organic aerosols (Tsigaridis et al, 2014) and tropospheric ozone, ozone's precursors and aerosols have been also evaluated against satellite and in situ observations Stohl et al, 2015;Quennehen et al, 2016;Myriokefalitakis et al, 2016).…”

Section: Model Descriptionmentioning

confidence: 99%

Bioavailable atmospheric phosphorous supply to the global ocean: a 3-D global modeling study

et al. 2016

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Abstract. The atmospheric cycle of phosphorus (P) is parameterized here in a state-of-the-art global 3-D chemistry transport model, taking into account primary emissions of total P (TP) and soluble P (DP) associated with mineral dust, combustion particles from natural and anthropogenic sources, bioaerosols, sea spray and volcanic aerosols. For the present day, global TP emissions are calculated to be roughly 1.33 Tg-P yr−1, with the mineral sources contributing more than 80 % to these emissions. The P solubilization from mineral dust under acidic atmospheric conditions is also parameterized in the model and is calculated to contribute about one-third (0.14 Tg-P yr−1) of the global DP atmospheric source. To our knowledge, a unique aspect of our global study is the explicit modeling of the evolution of phosphorus speciation in the atmosphere. The simulated present-day global annual DP deposition flux is 0.45 Tg-P yr−1 (about 40 % over oceans), showing a strong spatial and temporal variability. Present-day simulations of atmospheric P aerosol concentrations and deposition fluxes are satisfactory compared with available observations, indicating however an underestimate of about 70 % on current knowledge of the sources that drive the P atmospheric cycle. Sensitivity simulations using preindustrial (year 1850) anthropogenic and biomass burning emission scenarios showed a present-day increase of 75 % in the P solubilization flux from mineral dust, i.e., the rate at which P is converted into soluble forms, compared to preindustrial times, due to increasing atmospheric acidity over the last 150 years. Future reductions in air pollutants due to the implementation of air-quality regulations are expected to decrease the P solubilization flux from mineral dust by about 30 % in the year 2100 compared to the present day. Considering, however, that all the P contained in bioaerosols is readily available for uptake by marine organisms, and also accounting for all other DP sources, a total bioavailable P flux of about 0.17 Tg-P yr−1 to the oceans is derived. Our calculations further show that in some regions more than half of the bioavailable P deposition flux to the ocean can originate from biological particles, while this contribution is found to maximize in summer when atmospheric deposition impact on the marine ecosystem is the highest due to ocean stratification. Thus, according to this global study, a largely unknown but potentially important role of terrestrial bioaerosols as suppliers of bioavailable P to the global ocean is also revealed. Overall, this work provides new insights to the atmospheric P cycle by demonstrating that biological materials are important carriers of bioavailable P, with very important implications for past and future responses of marine ecosystems to global change.

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“…In a recent study, Myriokefalitakis et al (2016) have investigated the contribution of LRT to the O 3 and CO budget in the EM basin using a global chemistry-transport model (CTM), the TM4-ECPL, driven by ECMWF interim reanalysis project (ERA-Interim) meteorology. They found that about 8 % of surface O 3 concentrations are affected by local anthropogenic emissions, whereas subsiding air masses from the free troposphere and horizontal transport from surrounding regions provide about 38 and 51 % of O 3 sources, respectively, into the EM mixed-layer depth.…”

Section: Processes Controlling O 3 Formationmentioning

confidence: 99%

“…Another recent modeling study focused on CO concentrations was conducted by Myriokefalitakis et al (2016). They compared and validated model results against in situ observations at the surface, in the mixed layer, and in the free troposphere (between 850 hPa and the tropopause) in the countryside and remote atmosphere over Europe for 2008.…”

Section: Carbon Monoxide Sources and Pathwaysmentioning

confidence: 99%

“…The budget calculated for 2008 in the EM mixed layer, using a basic simulation relying on anthropogenic emissions and meteorology, points at a load of 0.6 Tg of CO, a chemical production of 10 Tg yr −1 , primary emissions in the region of 8 Tg yr −1 , and a dry deposition flux of 3 Tg yr −1 . Moreover, Myriokefalitakis et al (2016) found that subsidence from higher atmospheric layers typifying the EM summer is an important CO source (12 Tg yr −1 ) in the EM free troposphere. At the surface, anthropogenic local emissions in the EM were found to contribute 18 % to surface CO levels on an annual average.…”

Section: Carbon Monoxide Sources and Pathwaysmentioning

confidence: 99%

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Atmospheric pollution over the eastern Mediterranean during summer – a review

et al. 2017

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Abstract. The eastern Mediterranean (EM) is one of the regions in the world where elevated concentrations of primary and secondary gaseous air pollutants have been reported frequently, mainly in summer. This review discusses published studies of the atmospheric dispersion and transport conditions characterizing this region during the summer, followed by a description of some essential studies dealing with the corresponding concentrations of air pollutants such as ozone, carbon monoxide, total reactive nitrogen, methane, and sulfate aerosols observed there.The interlaced relationship between the downward motion of the subsiding air aloft induced by global circulation systems affecting the EM and the depth of the Persian Trough, a low-pressure trough that extends from the Asian monsoon at the surface controlling the spatiotemporal distribution of the mixed boundary layer during summer, is discussed. The strength of the wind flow within the mixed layer and its depth affect much the amount of pollutants transported and determine the potential of the atmosphere to disperse contaminants off their origins in the EM. The reduced mixed layer and the accompanying weak westerlies, characterizing the summer in this region, led to reduced ventilation rates, preventing an effective dilution of the contaminants. Several studies pointing at specific local (e.g., ventilation rates) and regional peculiarities (long-range transport) enhancing the build-up of air pollutant concentrations are presented.Tropospheric ozone (O 3 ) concentrations observed in the summer over the EM are among the highest over the Northern Hemisphere. The three essential processes controlling its formation (i.e., long-range transport of polluted air masses, dynamic subsidence at mid-tropospheric levels, and stratosphere-to-troposphere exchange) are reviewed. Airborne campaigns and satellite-borne initiatives have indicated that the concentration values of reactive nitrogen identified as precursors in the formation of O 3 over the EM were found to be 2 to 10 times higher than in the hemispheric background troposphere. Several factors favor sulfate particulate abundance over the EM. Models, aircraft measurements, and satellite-derived data have clearly shown that sulfate has a maximum during spring and summer over the EM. The carbon monoxide (CO) seasonal cycle, as obtained from global background monitoring sites in the EM, is mostly controlled by the tropospheric concentration of the hydroxyl radical (OH) and therefore demonstrates high concentrations over winter months and the lowest concentrations during summer when photochemistry is active. Modeling studies have shown that the diurnal variations in CO concentration during the summer result from long-range CO transport from European anthropogenic sources, contributing 60 to 80 % of the boundary-layer CO over the EM. The values retrieved from satellite data enable us to derive the spatial distribution of methane (CH 4 ), identifying August as the month with the highest levels over the EM. The outcomes of a...

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Ozone and carbon monoxide budgets over the Eastern Mediterranean

Abstract: 18The importance of the long-range transport (LRT) on O 3 and CO budgets over the Eastern 19 Mediterranean has been investigated using the state-of-the-art 3-dimensional global chemistry-20

Cited by 21 publications

References 54 publications

Meteorology and Climate Influences on Tropospheric Ozone: a Review of Natural Sources, Chemistry, and Transport Patterns

Meteorology and Climate Influences on Tropospheric Ozone: a Review of Natural Sources, Chemistry, and Transport Patterns

Bioavailable atmospheric phosphorous supply to the global ocean: a 3-D global modeling study

Atmospheric pollution over the eastern Mediterranean during summer – a review

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