scholarly journals Impact of the Asian monsoon anticyclone on the variability of mid-to-upper tropospheric methane above the Mediterranean Basin

2014 ◽  
Vol 14 (20) ◽  
pp. 11427-11446 ◽  
Author(s):  
P. Ricaud ◽  
B. Sič ◽  
L. El Amraoui ◽  
J.-L. Attié ◽  
R. Zbinden ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Near Infrared ◽  
Asian Monsoon ◽  
Climate Models ◽  
Transport Model ◽  
Lower Troposphere ◽  
Upper Troposphere ◽  
The Mediterranean ◽  
East West ◽  
The Mediterranean Basin

Abstract. The space and time variabilities of methane (CH4) total column and upper tropospheric mixing ratios are analysed above the Mediterranean Basin (MB) as part of the Chemical and Aerosol Mediterranean Experiment (ChArMEx) programme. Since the analysis of the mid-to-upper tropospheric CH4 distribution from spaceborne sensors and model outputs is challenging, we have adopted a climatological approach and have used a wide variety of data sets. We have combined spaceborne measurements from the Thermal And Near infrared Sensor for carbon Observations – Fourier Transform Spectrometer (TANSO-FTS) instrument on the Greenhouse gases Observing SATellite (GOSAT) satellite, the Atmospheric InfraRed Spectrometer (AIRS) on the AURA platform and the Infrared Atmospheric Sounder Interferometer (IASI) instrument aboard the MetOp-A platform with model results from the Chemical Transport Model (CTM) MOCAGE, and the Chemical Climate Models (CCMs) CNRM-AOCCM and LMDz-OR-INCA (according to different emission scenarios). In order to minimize systematic errors in the spaceborne measurements, we have only considered maritime pixels over the MB. The period of interest spans from 2008 to 2011 considering satellite and MOCAGE data and, regarding the CCMs, from 2001 to 2010. Although CH4 is a long-lived tracer with lifetime of ~12 years and is supposed to be well mixed in the troposphere, an east–west gradient in CH4 is observed and modelled in the mid-to-upper troposphere with a maximum in the Western MB in all seasons except in summer when CH4 accumulates above the Eastern MB. The peak-to-peak amplitude of the east–west seasonal variation in CH4 above the MB in the upper troposphere (300 hPa) is weak but almost twice as great in the satellite measurements (~25 ppbv) as in the model data (~15 ppbv). The maximum of CH4 in summer above the eastern MB can be explained by a series of dynamical processes only occurring in summer. The Asian monsoon traps and uplifts high amounts of CH4 to the upper troposphere where they build up. The Asian Monsoon Anticyclone redistributes these elevated CH4 amounts towards North Africa and the Middle East to finally reach and descend in the eastern MB. In the lower troposphere, the CH4 variability is mainly driven by the local sources of emission in the vicinity of the MB.

scholarly journals Variability of tropospheric methane above the Mediterranean Basin inferred from satellite and model data

2014 ◽  
Vol 14 (7) ◽  
pp. 9975-10024
Author(s):  
P. Ricaud ◽  
B. Sič ◽  
L. El Amraoui ◽  
J.-L. Attié ◽  
P. Huszar ◽  
...  
Keyword(s):  
Middle East ◽  
Atlantic Ocean ◽  
Mediterranean Basin ◽  
Near Infrared ◽  
Asian Monsoon ◽  
Transport Model ◽  
Emission Scenarios ◽  
The West ◽  
The Mediterranean ◽  
The Mediterranean Basin

Abstract. The space and time variabilities of methane (CH4) total column and upper tropospheric mixing ratios are analyzed above the Mediterranean Basin (MB) as part of the Chemical and Aerosol Mediterranean Experiment (ChArMEx) programme. Spaceborne measurements from the Thermal And Near infrared Sensor for carbon Observations-Fourier Transform Spectrometer (TANSO-FTS) instrument on the Greenhouse gases Observing SATellite (GOSAT) satellite, the Atmospheric InfraRed Spectrometer (AIRS) on the AURA platform and the Infrared Atmospheric Sounder Interferometer (IASI) instrument aboard the MetOp-A platform are used in conjunction with model results from the Chemical Transport Model (CTM) MOCAGE, and the Chemical Climate Models (CCMs) CNRM-AOCCM and LMDz-OR-INCA (according to different emission scenarios). In order to minimize systematic errors in the spaceborne measurements, we have only considered maritime pixels over the MB. The period under interest spans from 2008 to 2011 considering satellite and MOCAGE data and, regarding the CCMs, from 2001 to 2010. An East-West gradient in CH4 is observed and modelled whatever the season considered. In winter, air masses mainly originating from Atlantic Ocean and Europe tend to favour an elevated amount of mid-to-upper tropospheric CH4 in the West vs. the East of the MB, with a general upward transport above the MB. In summer, the meteorological state of the MB is changed, favouring air from Northern Africa and Middle East together with Atlantic Ocean and Europe, with a general downward motion above the MB. The Asian Monsoon traps and uplifts high amounts of CH4 that are transported towards North Africa and Middle East by the Asian Monsoon Anticyclone to finally reach and descent in the East of the MB. Consequently, the mid-to-upper tropospheric CH4 is much greater in the East than in the West of the MB. The seasonal variation of the difference in CH4 between the East and the West MB does show a maximum in summer for pressures from 500 to 100 hPa considering both spaceborne measurements and model results whatever the emission scenarios used. From this study, we can conclude that CH4 in the mid-to-upper troposphere over the MB is mainly affected by long-range transport, particularly intense in summer from Asia. In the low-to-mid troposphere, the local sources of emission in the vicinity of the MB mainly affect the CH4 variability.

scholarly journals Primary aerosol and secondary inorganic aerosol budget over the Mediterranean Basin during 2012 and 2013

2018 ◽  
Vol 18 (7) ◽  
pp. 4911-4934 ◽  
Author(s):  
Jonathan Guth ◽  
Virginie Marécal ◽  
Béatrice Josse ◽  
Joaquim Arteta ◽  
Paul Hamer
Keyword(s):  
Mediterranean Basin ◽  
Transport Model ◽  
Coastal Areas ◽  
Sea Salt ◽  
Anthropogenic Emissions ◽  
Carbonaceous Aerosols ◽  
Desert Dust ◽  
Inorganic Aerosols ◽  
The Mediterranean ◽  
The Mediterranean Basin

Abstract. In the frame of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx), we analyse the budget of primary aerosols and secondary inorganic aerosols over the Mediterranean Basin during the years 2012 and 2013. To do this, we use two year-long numerical simulations with the chemistry-transport model MOCAGE validated against satellite- and ground-based measurements. The budget is presented on an annual and a monthly basis on a domain covering 29 to 47° N latitude and 10° W to 38° E longitude. The years 2012 and 2013 show similar seasonal variations. The desert dust is the main contributor to the annual aerosol burden in the Mediterranean region with a peak in spring, and sea salt being the second most important contributor. The secondary inorganic aerosols, taken as a whole, contribute a similar level to sea salt. The results show that all of the considered aerosol types, except for sea salt aerosols, experience net export out of our Mediterranean Basin model domain, and thus this area should be considered as a source region for aerosols globally. Our study showed that 11 % of the desert dust, 22.8 to 39.5 % of the carbonaceous aerosols, 35 % of the sulfate and 9 % of the ammonium emitted or produced into the study domain are exported. The main sources of variability for aerosols between 2012 and 2013 are weather-related variations, acting on emissions processes, and the episodic import of aerosols from North American fires. In order to assess the importance of the anthropogenic emissions of the marine and the coastal areas which are central for the economy of the Mediterranean Basin, we made a sensitivity test simulation. This simulation is similar to the reference simulation but with the removal of the international shipping emissions and the anthropogenic emissions over a 50 km wide band inland along the coast. We showed that around 30 % of the emissions of carbonaceous aerosols and 35 to 60 % of the exported carbonaceous aerosols originates from the marine and coastal areas. The formation of 23, 27 and 27 %, respectively of, ammonium, nitrate and sulfate aerosols is due to the emissions within the marine and coastal area.

scholarly journals Modulation of the Occurrence of Heatwaves over the Euro-Mediterranean Region by the Intensity of the Atlantic Multidecadal Variability

2021 ◽  
Vol 34 (3) ◽  
pp. 1099-1114
Author(s):  
Saïd Qasmi ◽  
Emilia Sanchez-Gomez ◽  
Yohan Ruprich-Robert ◽  
Julien Boé ◽  
Christophe Cassou
Keyword(s):  
Mediterranean Basin ◽  
Climate Models ◽  
Sensible Heat Flux ◽  
Forced Response ◽  
Atlantic Multidecadal Variability ◽  
Multidecadal Variability ◽  
Local Climate ◽  
Large Ensembles ◽  
The Mediterranean ◽  
The Mediterranean Basin

AbstractThe influence of the Atlantic multidecadal variability (AMV) and its amplitude on the Euro-Mediterranean summer climate is studied in two climate models, namely CNRM-CM5 and EC-Earth3P. Large ensembles of idealized experiments have been conducted in which North Atlantic sea surface temperatures are relaxed toward different amplitudes of the observed AMV anomalies. In agreement with observations, during a positive phase of the AMV both models simulate an increase (decrease) in temperature of 0.2°–0.8°C and a decrease (increase) in precipitation over the Mediterranean basin of 0.1–0.2 mm day−1 (northern half of Europe) compared to a negative phase. Heatwave durations over the Mediterranean land regions are 40% (up to 85% over the eastern regions) longer for a moderate amplitude of the AMV. Lower and higher amplitudes lead to longer durations of ~30% and ~100%, respectively. A comparison with observed heatwaves indicates that the AMV can considerably modulate the current anthropogenically forced response on heatwaves durations depending on the area and on the AMV amplitude. The related anticyclonic anomalies over the Mediterranean basin are associated with drier soils and a reduction of cloud cover, which concomitantly induce a decrease (increase) of the latent (sensible) heat flux, and an enhancement of the downward radiative fluxes over lands. It is found that both tropical and extratropical forcings from the AMV are needed to trigger mechanisms, which modulate the atmospheric circulation over the Euro-Atlantic region. The amplitude of the local climate response over the Mediterranean basin evolves linearly with the amplitude of the AMV. However, the strength of this relationship differs between the models, and depends on their intrinsic biases.

scholarly journals Comparing naturalized alien plants and recipient habitats across an east-west gradient in the Mediterranean Basin

2010 ◽  
Vol 37 (9) ◽  
pp. 1811-1823 ◽  
Author(s):  
Margarita Arianoutsou ◽  
Pinelopi Delipetrou ◽  
Laura Celesti-Grapow ◽  
Corina Basnou ◽  
Ioannis Bazos ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Alien Plants ◽  
The Mediterranean ◽  
East West ◽  
The Mediterranean Basin

scholarly journals Tracking the emission and transport of pollution from wildfires using the IASI CO retrievals: analysis of the summer 2007 Greek fires

2009 ◽  
Vol 9 (2) ◽  
pp. 7413-7455 ◽  
Author(s):  
S. Turquety ◽  
D. Hurtmans ◽  
J. Hadji-Lazaro ◽  
P.-F. Coheur ◽  
C. Clerbaux ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Lower Troposphere ◽  
General Level ◽  
Vertical Resolution ◽  
Backscatter Coefficient ◽  
Fire Emissions ◽  
Boundary Layer Height ◽  
Independent Information ◽  
The Mediterranean ◽  
The Mediterranean Basin

Abstract. In this paper, we analyze the performance of the Infrared Atmospheric Sounding Interferometer (IASI), launched in October 2006 on board METOP-A, for the monitoring of carbon monoxide (CO) during extreme fire events, focusing on the record-breaking fires which devastated thousands of square kilometers of forest in Greece during the last week (23–30) of August 2007. After an assessment of the quality of the profiles retrieved using the Fast Optimal Retrievals on Layers for IASI (FORLI) algorithm, the information provided on fire emissions and subsequent pollution outflow is discussed. Large CO plumes were observed above the Mediterranean Basin and North Africa, with total CO columns exceeding 30×1018 molecules/cm2 and absolute volume mixing ratio up to 22 ppmv. The average root-mean-square (RMS) difference between simulated and observed spectra is close to the estimated radiometric noise level, slightly increasing (by ~14%) in the fresh fire plumes. CO profiles are retrieved with a vertical resolution of about 8 km, with ~1.7 pieces of independent information on the vertical in the region considered and a maximum sensitivity in the free troposphere (~4–5 km). Using the integrated total amount, the increase in CO burden due to these fires is estimated to 0.321 Tg, ~40% of the total annual anthropogenic emissions in Greece. These CO enhancements are in good agreement with the aerosol optical depth (AOD) retrieved from the MODIS measurements, highlighting a rapid transport of trace gases and aerosols across the Mediterranean Basin (less than one day). While the coarse vertical resolution will not allow the location of the exact plume height, the large CO enhancements observed in the lower troposphere are consistent with the maximum aerosol backscatter coefficient at ~2 km detected by the CALIPSO lidar in space (CALIOP). This indicates that the general level of transport can be derived (lower, middle or upper troposphere) but that it needs to be accompanied by a systematic confrontation with sensitivity profiles and boundary layer height.

scholarly journals Intercontinental transport of biomass burning pollutants over the Mediterranean Basin during the summer 2014 ChArMEx-GLAM airborne campaign

2018 ◽  
Vol 18 (9) ◽  
pp. 6887-6906 ◽  
Author(s):  
Vanessa Brocchi ◽  
Gisèle Krysztofiak ◽  
Valéry Catoire ◽  
Jonathan Guth ◽  
Virginie Marécal ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Mediterranean Basin ◽  
Transport Model ◽  
Particle Dispersion ◽  
Transport Processes ◽  
Atmospheric Composition ◽  
Air Mass ◽  
Air Masses ◽  
The Mediterranean ◽  
The Mediterranean Basin

Abstract. The Gradient in Longitude of Atmospheric constituents above the Mediterranean basin (GLAM) campaign was set up in August 2014, as part of the Chemistry and Aerosol Mediterranean Experiment (ChArMEx) project. This campaign aimed to study the chemical variability of gaseous pollutants and aerosols in the troposphere along a west–east transect above the Mediterranean Basin (MB). In the present work, we focus on two biomass burning events detected at 5.4 and 9.7 km altitude above sea level (a.s.l.) over Sardinia (from 39∘12′ N–9∘15′ E to 35∘35′ N–12∘35′ E and at 39∘30′ N–8∘25′ E, respectively). Concentration variations in trace gas carbon monoxide (CO), ozone (O3) and aerosols were measured thanks to the standard instruments on board the Falcon 20 aircraft operated by the Service des Avions Français Instrumentés pour la Recherche en Environnement (SAFIRE) and the Spectromètre InfraRouge In situ Toute Altitude (SPIRIT) developed by LPC2E. Twenty-day backward trajectories with Lagrangian particle dispersion model FLEXPART (FLEXible PARTicle) help to understand the transport processes and the origin of the emissions that contributed to this pollution detected above Sardinia. Biomass burning emissions came (i) on 10 August from the North American continent with air masses transported during 5 days before arriving over the MB, and (ii) on 6 August from Siberia, with air masses travelling during 12 days and enriched in fire emission products above Canada 5 days before arriving over the MB. In combination with the Global Fire Assimilation System (GFAS) inventory and the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite fire locations, FLEXPART reproduces well the contribution of those fires to CO and aerosols enhancements under adjustments of the injection height to 10 km in both cases and application of an amplification factor of 2 on CO GFAS emissions for the 10 August event. The chemistry transport model (CTM) MOCAGE is used as a complementary tool for the case of 6 August to confirm the origin of the emissions by tracing the CO global atmospheric composition reaching the MB. For this event, both models agree on the origin of air masses with CO concentrations simulated with MOCAGE lower than the observed ones, likely caused by the coarse model horizontal resolution that yields the dilution of the emissions and diffusion during transport. In combination with wind fields, the analysis of the transport of the air mass documented on 6 August suggests the subsidence of CO pollution from Siberia towards North America and then a transport to the MB via fast jet winds located at around 5.5 km in altitude. Finally, using the ratio ΔO3 ∕ ΔCO, the plume age can be estimated and the production of O3 during the transport of the air mass is studied using the MOCAGE model.

scholarly journals The Mediterranean summertime ozone maximum: global emission sensitivities and radiative impacts

2013 ◽  
Vol 13 (5) ◽  
pp. 2331-2345 ◽  
Author(s):  
N. A. D. Richards ◽  
S. R. Arnold ◽  
M. P. Chipperfield ◽  
G. Miles ◽  
A. Rap ◽  
...  
Keyword(s):  
Lower Troposphere ◽  
Emission Sources ◽  
Voc Emissions ◽  
Upper Troposphere ◽  
Ozone Sensitivity ◽  
Ozone Maximum ◽  
Local Emission ◽  
Non Local ◽  
The Mediterranean ◽  
The Mediterranean Basin

Abstract. The Mediterranean troposphere exhibits a marked and localised summertime ozone maximum, which has the potential to strongly impact regional air quality and radiative forcing. The Mediterranean region can be perturbed by long-range pollution import from Northern Europe, North America and Asia, in addition to local emissions, which may all contribute to regional ozone enhancements. We exploit ozone profile observations from the Tropospheric Emission Spectrometer (TES) and the Global Ozone Monitoring Experiment-2 (GOME-2) satellite instruments, and an offline 3-D global chemical transport model (TOMCAT) to investigate the geographical and vertical structure of the summertime tropospheric ozone maximum over the Mediterranean region. We show that both TES and GOME-2 are able to detect enhanced levels of ozone in the lower troposphere over the region during the summer. These observations, together with surface measurements, are used to evaluate the TOMCAT model's ability to capture the observed ozone enhancement. The model is used to quantify sensitivities of the ozone maximum to anthropogenic and natural volatile organic compound (VOC) emissions, anthropogenic NOx emissions, wildfire emissions and long-range import of ozone and precursors. Our results show a dominant sensitivity to natural VOC emissions in the Mediterranean basin over anthropogenic VOC emissions. However, local anthropogenic NOx emissions are result in the overall largest sensitivity in near-surface ozone. We also show that in the lower troposphere, global VOC emissions account for 40% of the ozone sensitivity to VOC emissions in the region, whereas, for NOx the ozone sensitivity to local sources is 9 times greater than that for global emissions at these altitudes. However, in the mid and upper troposphere ozone is most sensitive to non-local emission sources. In terms of radiative effects on regional climate, ozone contributions from non-local emission sources are more important, as these have a larger impact on ozone in the upper troposphere where its radiative effects are larger, with Asian monsoon outflow having the greatest impact. Our results allow improved understanding of the large-scale processes controlling air quality and climate in the region of the Mediterranean basin.

scholarly journals Primary aerosols and secondary inorganic aerosols budget over the Mediterranean basin during 2012 and 2013

2017 ◽  
Author(s):  
Jonathan Guth ◽  
Virginie Marécal ◽  
Béatrice Josse ◽  
Joaquim Arteta
Keyword(s):  
Mediterranean Basin ◽  
Transport Model ◽  
Wide Band ◽  
Sea Salts ◽  
Monthly Basis ◽  
Desert Dust ◽  
Inorganic Aerosols ◽  
Sulphate Aerosols ◽  
The Mediterranean ◽  
The Mediterranean Basin

Abstract. In the frame of the Chemistry-Aerosol Mediterranean Experiment (ChArMEx), we analyse the budget of primary aerosols and secondary inorganic aerosols over the Mediterranean basin during the years 2012 and 2013. To do this, we use a two-years long numerical simulation with the Chemistry-Transport Model MOCAGE validated against satellite and ground based measurements. The budget is presented on an annual and a monthly basis on a domain covering 29° North to 47° North latitude and 10° West to 38° East longitude. The years 2012 and 2013 show similar seasonal variations. The desert dust is the main contributor to the annual burden in the Mediterranean region with a peak in spring. The secondary inorganic aerosols, taken as a whole, also contribute significantly as well as sea salts. Sulphate aerosols have a maximum in summer and sea salts in winter, while nitrate and ammonium aerosols do not exhibit large seasonal changes. The results show that all the considered types of aerosols, except for sea salt aerosols, have a net import/export term that is negative, meaning that aerosols emitted and chemically produced within the domain are transported out, with high values for some of them. For example, around 40 % of the emitted black carbon are exported. The main sources of changes between 2012 and 2013 are wind variations acting on the desert dust emissions and the import of aerosols from North American fires. In order to assess the importance of the emissions of the marine and the coastal areas, we made a sensitivity test simulation. This simulation is similar to the first one but with the removal of the anthropogenic emissions over the sea and over a 50 km wide band inland along the coast. It shows that about a third of the aerosols emitted and chemically produced and about a half of the exported part in the Mediterranean basin originate from the marine and coastal area, meaning that anthropogenic air pollution from primary aerosols and secondary inorganic aerosols in this region mainly comes from local emissions.

scholarly journals Tracking the emission and transport of pollution from wildfires using the IASI CO retrievals: analysis of the summer 2007 Greek fires

2009 ◽  
Vol 9 (14) ◽  
pp. 4897-4913 ◽  
Author(s):  
S. Turquety ◽  
D. Hurtmans ◽  
J. Hadji-Lazaro ◽  
P.-F. Coheur ◽  
C. Clerbaux ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Lower Troposphere ◽  
Vertical Resolution ◽  
Backscatter Coefficient ◽  
Fire Emissions ◽  
Mixing Ratios ◽  
Absolute Volume ◽  
Independent Information ◽  
The Mediterranean ◽  
The Mediterranean Basin

Abstract. In this paper, we analyze the performance of the Infrared Atmospheric Sounding Interferometer (IASI), launched in October 2006 on board METOP-A, for the monitoring of carbon monoxide (CO) during extreme fire events, focusing on the record-breaking fires which devastated thousands of square kilometers of forest in Greece during the last week (23–30) of August 2007. After an assessment of the quality of the profiles retrieved using the Fast Optimal Retrievals on Layers for IASI (FORLI) algorithm, the information provided on fire emissions and subsequent pollution outflow is discussed. Large CO plumes were observed above the Mediterranean Basin and North Africa, with total CO columns exceeding 24×1018 molecules/cm2 and absolute volume mixing ratios up to 4 ppmv on the 25 August. Up to 30×1018 molecules/cm2 and 22 ppmv in the lower troposphere are retrieved close to the fires above the Peloponnese, but with larger uncertainty. The average root-mean-square (RMS) difference between simulated and observed spectra is close to the estimated radiometric noise level, slightly increasing (by ~14%) in the fresh fire plumes. CO profiles are retrieved with a vertical resolution of about 8 km, with ~1.7 pieces of independent information on the vertical in the region considered and a maximum sensitivity in the free troposphere (~4–5 km). Using the integrated total amount, the increase in CO burden due to these fires is estimated to 0.321 Tg, ~40% of the total annual anthropogenic emissions in Greece. The patterns of these CO enhancements are in good agreement with the aerosol optical depth (AOD) retrieved from the MODIS measurements, highlighting a rapid transport of trace gases and aerosols across the Mediterranean Basin (less than one day). While the coarse vertical resolution will not allow the location of the exact plume height, the large CO enhancements observed in the lower troposphere are consistent with the maximum aerosol backscatter coefficient at ~2 km detected by the CALIPSO lidar in space (CALIOP).

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