scholarly journals Comparison of two different sea-salt aerosol schemes as implemented in air quality models applied to the Mediterranean Basin

2011 ◽  
Vol 11 (10) ◽  
pp. 4833-4850 ◽  
Author(s):  
P. Jiménez-Guerrero ◽  
O. Jorba ◽  
M. T. Pay ◽  
J. P. Montávez ◽  
S. Jerez ◽  
...  

Abstract. A number of attempts have been made to incorporate sea-salt aerosol (SSA) source functions in chemistry transport models with varying results according to the complexity of the scheme considered. This contribution compares the inclusion of two different SSA algorithms in two chemistry transport models: CMAQ and CHIMERE. The main goal is to examine the differences in average SSA mass and composition and to study the seasonality of the prediction of SSA when applied to the Mediterranean area with high resolution for a reference year. Dry and wet deposition schemes are also analyzed to better understand the differences observed between both models in the target area. The applied emission algorithm in CHIMERE uses a semi-empirical formulation which obtains the surface emission rate of SSA as a function of the particle size and the surface wind speed raised to the power 3.41. The emission parameterization included within CMAQ is somehow more sophisticated, since fluxes of SSA are corrected with relative humidity. In order to evaluate their strengths and weaknesses, the participating algorithms as implemented in the chemistry transport models were evaluated against AOD measurements from Aeronet and available surface measurements in Southern Europe and the Mediterranean area, showing biases around −0.002 and −1.2 μg m−3, respectively. The results indicate that both models represent accurately the patterns and dynamics of SSA and its non-uniform behavior in the Mediterranean basin, showing a strong seasonality. The levels of SSA strongly vary across the Western and the Eastern Mediterranean, reproducing CHIMERE higher annual levels in the Aegean Sea (12 μg m−3) and CMAQ in the Gulf of Lion (9 μg m−3). The large difference found for the ratio PM2.5/total SSA in CMAQ and CHIMERE is also investigated. The dry and wet removal rates are very similar for both models despite the different schemes implemented. Dry deposition essentially follows the surface drag stress patterns, meanwhile wet deposition is more scattered over the continent. CMAQ tends to provide larger amounts of SSA dry deposition over the Northern Mediterranean (0.7–1.0 g m−2 yr−1), meanwhile the Southeastern Mediterranean accounts for the maximum annual dry deposition in the CHIMERE model (0.9–1.5 g m−2 yr−1). The wet deposition is dominated by the accumulation mode and is strongly correlated to the precipitation patterns, showing CMAQ a higher wet deposition/total deposition ratio over coastal mountain chains. The results of both models constitute a step towards increasing the understanding of the SSA dynamics in a complex area as the Mediterranean.

2010 ◽  
Vol 10 (12) ◽  
pp. 30999-31038
Author(s):  
P. Jimenez-Guerrero ◽  
O. Jorba ◽  
M. T. Pay ◽  
J. P. Montavez ◽  
S. Jerez ◽  
...  

Abstract. A number of attempts have been made to incorporate sea-salt aerosols (SSA) source functions in chemistry transport models with varying results according to the complexity of the scheme considered. This contribution compares the inclusion of two different SSA algorithms in two chemistry transport models: CMAQ and CHIMERE. The main goal is to examine the differences in average SSA mass and composition and to study the seasonality of the prediction of SSA when applied to the Mediterranean area with high resolution in a reference year. Dry and wet deposition schemes are also analyzed to better understand the differences observed between both models in the target area. The applied emission algorithm in CHIMERE uses a semi-empirical formulation which obtains the surface emission rate of SSA as a function of the surface wind speed cubed and particle size. The emission parameterization included within CMAQ is somehow more sophisticated, since fluxes of SSA are corrected with relative humidity. In order to evaluate their strengths and weaknesses, the participating algorithms as implemented in the chemistry transport models were evaluated against AOD measurements from Aeronet and available surface measurements in Southern Europe and the Mediterranean area, showing biases around −0.003 and −1.2 μg m−3, respectively. The results indicate that both models represent accurately the patterns and dynamics of SSA and its non-uniform behavior in the Mediterranean basin, showing a strong seasonality. The levels of SSA vary strongly across the Western and the Eastern Mediterranean, reproducing CHIMERE higher annual levels in the Aegean Sea (12 μg m−3) and CMAQ in the Gulf of Lion (9 μg m−3). The large difference found for the ratio PM2.5/total SSA in CMAQ and CHIMERE is also investigated. The dry and wet removal rates are very similar for both models despite the different schemes implemented. Dry deposition essentially follows the surface drag stress patterns, meanwhile wet deposition is more scattered over the continent. CMAQ tends to provide larger amounts of SSA dry deposition over the Northern Mediterranean (0.7–1.0 g m−2 yr−1), meanwhile the Southeastern Mediterranean accounts for the maximum annual dry deposition in the CHIMERE model (0.9–1.5 g m−2 yr−1). The wet deposition is dominated by the accumulation mode and is strongly correlated to the precipitation patterns, showing CMAQ a higher wet deposition/total deposition ratio over coastal mountain chains. The results of both models constitute a step towards increasing the understanding of the SSA dynamics in a complex area as the Mediterranean.


2018 ◽  
Vol 18 (7) ◽  
pp. 4911-4934 ◽  
Author(s):  
Jonathan Guth ◽  
Virginie Marécal ◽  
Béatrice Josse ◽  
Joaquim Arteta ◽  
Paul Hamer

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.


2015 ◽  
Vol 15 (14) ◽  
pp. 20013-20057
Author(s):  
G. Calzolai ◽  
S. Nava ◽  
F. Lucarelli ◽  
M. Chiari ◽  
M. Giannoni ◽  
...  

Abstract. The Mediterranean Basin atmosphere is influenced by both strong natural and anthropogenic aerosol emissions, and is also subject to important climatic forcings. Several programs have addressed the study of the Mediterranean basin; nevertheless important pieces of information are still missing. In this framework, PM10 samples were collected on a daily basis on the island of Lampedusa (35.5° N, 12.6° E, 45 m a.s.l.), which is far from continental pollution sources (the nearest coast, in Tunisia, is more than 100 km away). After mass gravimetric measurements, different portions of the samples were analyzed to determine the ionic content by Ion Chromatography (IC), the soluble metals by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), and the total (soluble + insoluble) elemental composition by Particle Induced X-ray Emission (PIXE). Data from years 2007 and 2008 are used in this study. The Positive Matrix Factorization (PMF) model was applied to the 2 year long data set of PM10 mass concentration and chemical composition to assess the aerosol sources affecting the Central Mediterranean basin. Seven sources were resolved: sea-salt, mineral dust, biogenic emissions, primary particulate ship emissions, secondary sulphate, secondary nitrate, and combustion emissions. Source contributions to the total PM10 mass were estimated to be about 40 % for sea-salt, around 25 % for mineral dust, 10 % each for secondary nitrate and secondary sulphate, and 5 % each for primary particulate ship emissions, biogenic emissions, and combustion emissions. Large variations in absolute and relative contributions are found and appear to depend on the season and on transport episodes. In addition, the secondary sulphate due to ship emissions was estimated, and found to contribute by about one third to the total sulphate mass. Results for the sea-salt and mineral dust sources were compared with estimates of the same contributions obtained from independent approaches, leading to an estimate of the water content bound to the sea salt in the marine source.


2015 ◽  
Vol 15 (24) ◽  
pp. 13939-13955 ◽  
Author(s):  
G. Calzolai ◽  
S. Nava ◽  
F. Lucarelli ◽  
M. Chiari ◽  
M. Giannoni ◽  
...  

Abstract. The Mediterranean Basin atmosphere is influenced by both strong natural and anthropogenic aerosol emissions and is also subject to important climatic forcings. Several programs have addressed the study of the Mediterranean basin; nevertheless important pieces of information are still missing. In this framework, PM10 samples were collected on a daily basis on the island of Lampedusa (35.5° N, 12.6° E; 45 m a.s.l.), which is far from continental pollution sources (the nearest coast, in Tunisia, is more than 100 km away). After mass gravimetric measurements, different portions of the samples were analyzed to determine the ionic content by ion chromatography (IC), the soluble metals by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the total (soluble + insoluble) elemental composition by particle-induced x-ray emission (PIXE). Data from 2007 and 2008 are used in this study. The Positive Matrix Factorization (PMF) model was applied to the 2-year long data set of PM10 mass concentration and chemical composition to assess the aerosol sources affecting the central Mediterranean basin. Seven sources were resolved: sea salt, mineral dust, biogenic emissions, primary particulate ship emissions, secondary sulfate, secondary nitrate, and combustion emissions. Source contributions to the total PM10 mass were estimated to be about 40 % for sea salt, around 25 % for mineral dust, 10 % each for secondary nitrate and secondary sulfate, and 5 % each for primary particulate ship emissions, biogenic emissions, and combustion emissions. Large variations in absolute and relative contributions are found and appear to depend on the season and on transport episodes. In addition, the secondary sulfate due to ship emissions was estimated and found to contribute by about one-third to the total sulfate mass. Results for the sea-salt and mineral dust sources were compared with estimates of the same contributions obtained from independent approaches, leading to an estimate of the water content bound to the sea salt in the marine source.


2021 ◽  
Author(s):  
Arianna Facchi ◽  

<p>In the Mediterranean basin, rice is cultivated over an area of 1,300,000 hectares. The most important rice-producing countries are Italy and Spain in Europe (72% of the EU production; 345,000 ha), and Egypt and Turkey among the extra-EU countries (almost totality of the production; 789,000 ha). Traditionally, rice is grown under continuous flooding; thus, it requires more water than non-ponded crops. On the other hand, rice is strategic for food security in some countries such as Egypt, and human consumption in the whole Mediterranean is steadily increasing.</p><p>The MEDWATERICE project (PRIMA-Section 2-2018; https://www.medwaterice.org/), which started in April 2019, aims to explore the sustainability of innovative rice irrigation methods and technologies in the Mediterranean basin, in order to reduce rice water use and environmental impacts, and to extend rice cultivation outside of traditional paddy areas to meet the growing demand. The MEDWATERICE consortium includes universities, research centres and private companies operating in the Mediterranean area (IT, ES, PT, EG, TR, IL). Case studies (CSs) are implemented in pilot farms of the countries involved in the project. Tested alternative irrigation methods and technologies adopted in each CS are being tailored to local conditions using a participatory action research approach through the establishment of Stake-Holder Panels in each country, which include regional authorities, water managers, farmers’ associations and consultants, and private companies of the rice production chain. Irrigation strategies experimented in the pilot farms and compared to the continuous flooding (considered as the ‘reference’ irrigation method in all CSs), are: dry seeding and delayed flooding, alternate wetting and drying, lengthening of drying periods, reduction in irrigation inflow/outflow, hybrid irrigation, multi-nozzle sprinkler irrigation, surface and sub-surface drip irrigation, and waste-water reuse through sub-surface drip irrigation. For each irrigation solution, innovative technologies and the most appropriate rice varieties and agronomic practices are tested to minimize impacts of irrigation water reduction on yield quantity and quality. Data collected at the farm level are extrapolated to the irrigation district level to support water management decisions and policies. Indicators for quantitative assessment of environmental, economic and social sustainability of the irrigation options are also being defined. Outcomes produced by MEDWATERICE are expected to generate knowledge on how to improve sustainability of rice production in the countries of the Mediterranean area, with particular attention to the adoption of water-saving techniques.</p><p>During the conference, approaches and methodologies adopted and developed within the project, and results obtained so far will be presented, with particular attention to the experimentation conducted in the pilot farms, to the methods for the upscaling the achievements to the irrigation district scale, and to the set of indicators for quantifying economic, environmental and social sustainability of irrigation methods and technologies currently under definition.</p>


1982 ◽  
Vol 47 (1) ◽  
pp. 87-98 ◽  
Author(s):  
Stephen L. Dyson

The aim of this article is to describe and discuss the use of archaeological survey in the Mediterranean area during recent decades. Emphasis will be placed on research conducted since World War II, and I will concentrate primarily on Greece and the Western Mediterranean. In this context, surveys centering on later prehistoric and historic periods will receive most attention. Note that even within these areas of concentration, this article cannot claim to be exhaustive. It is my intention to discuss the highlights of this rapidly developing field.


Author(s):  
Temani R

Uppermost Miocene stratigraphic sections have been sampled in Sicily and eastern Tunisia. Some of the stratigraphic levels contained in them are related to the continentalization phase (“Lago Mare”) of the Mediterranean Basin, which occurred at the end of the Messinian Salinity Crisis. Within these levels, ostracod associations reflecting fresh or brackish water environments are reported here for the first time. Species considered to be Paratethyan in affinity lived in these environments. The discovery, both in Sicily and Tunisia, of species such as C agrigentina, A propinqua, and M. punctate, suggests that the Sicilian Channel did not prevent the migration of the non-marine fauna from NW to SE in the Paleomediterranean area during the Post Evaporitic Phase


2015 ◽  
Vol 15 (6) ◽  
pp. 8191-8242 ◽  
Author(s):  
G. Rea ◽  
S. Turquety ◽  
L. Menut ◽  
R. Briant ◽  
S. Mailler ◽  
...  

Abstract. In the Mediterranean area, aerosols may originate from anthropogenic or natural emissions (biogenic, mineral dust, fire and sea salt) before undergoing complex chemistry. In case of a huge pollution event, it is important to know if european pollution limits are exceeded and, if yes, if the pollution is due to anthropogenic or natural sources. In this study, the relative contribution of emissions to surface PM10, surface PM2.5 and total aerosol optical depth (AOD) is quantified. For Europe and the Mediterranean regions and during the summer of 2012, the WRF and CHIMERE models are used to perform a sensitivity analysis: one simulation with all sources (reference) and all others with one source removed. The reference simulation is compared to data from the AirBase and AERONET networks and the MODIS satellite instrument to quantify the ability of the model to reproduce the observations. It is shown that the correlation ranges from 0.38 to 0.49 for surface particulate matter and from 0.35 to 0.75 for AOD. The sensitivity simulations are analysed to quantify the impact of each source. For the summer of 2012, the model shows that the region (from −10° W to 40° E and from 30 to 55° N) is mainly influenced by aerosols due to mineral dust and anthropogenic emissions (62 and 19% respectively of total surface PM10 and 17 and 52% of total surface PM2.5). The western part of the Mediterranean is strongly influenced by mineral dust emissions (86% for surface PM10 and 44% for PM2.5), while anthropogenic emissions dominate in the northern Mediterranean basin (up to 75% for PM2.5). Fire emissions are more sporadic but may represent 20% of surface PM2.5 near local sources. Sea salt mainly contribute for coastal sites (up to 29%) and biogenic emissions mainly in Central Europe (up to 20%). The same analysis was undertaken for the number of stations in daily exceedances of the European Union limit of 50 μg m−3 for PM10 (over the AirBase stations). This number is generally overestimated by the model, particularly in the northern part of the domain, but exceedances are captured at the right time. The discrepancies are most probably due to an overestimation of dust at the surface, and particularly when diverse sources are mixed. If natural sources as mineral dust events are particularly difficult to estimate, their contribution to the exceedances of the limitation is preponderant during the summer of 2012 (from 35% in the northern part of the Mediterranean basin to 92.5% in the western part).


1997 ◽  
Vol 40 (1) ◽  
Author(s):  
M. D. Martínez ◽  
X. Lana ◽  
J. Badal ◽  
J. A. Canas ◽  
L. Pujades

An objective regionalization of the Mediterranean basin is derived from a tomographic study based on the fundamental mode of Rayleigh waves. The database is formed by seismic wavetrains recorded at very-broadband stations belonging to MedNet and other cooperative stations, located in the Mediterranean area. The data treatment consists of application of spectral filtering techniques aimed to determine path-averaged group velocities, computation of local group velocity maps for some periods and classification of the studied area in several homogeneous regions according to Principal Component Analysis (PCA) and Average Linkage (AL) algorithms. Finally, the group velocity dispersion curves representing each homogeneous region are compared and possible correlation between these regions and seismotectonic and structural characteristics are discussed.


2019 ◽  
Vol 12 (10) ◽  
pp. 1630-1643 ◽  
Author(s):  
Djamel Tahir ◽  
Bernard Davoust ◽  
Philippe Parola

Vector-borne diseases (VBDs) are among the leading causes of morbidity and mortality in humans and animals. The scale of VBDs is increasing worldwide, including in the Mediterranean Basin, a region exposed to climate changes. Indeed, weather conditions may influence the abundance and distribution of vectors. The vector-borne nematode diseases of dogs and cats, such as dirofilariosis, onchocercosis, thelaziosis, Cercopithifilaria, and Acanthocheilonema infections, are some of these vectorized diseases, several of which are zoonoses. They are all caused by parasitic nematodes transmitted by arthropods, including mosquitoes (Dirofilaria spp.), black flies (Onchocerca lupi), drosophilids (Thelazia callipaeda), ticks (Acanthocheilonema dracunculoides and Cercopithifilaria bainae), and fleas and lice (Acanthocheilonema reconditum). The control and prevention of these infections and diseases require a multidisciplinary approach based on strengthening collaboration between the different actors in the fields of health, research, sociology, economics, governments and citizens, to improve human, animal, and ecosystem health. This is the concept of "one health." The review aimed to provide a general update on the spatial and temporal distribution of vector-borne nematodes diseases affecting companion animals and humans, as well as the vectors involved in the Mediterranean area. Simultaneously, certain epidemiological parameters, diagnosis, treatment, and control of these diseases based on the "one health" concept will also be discussed.


Sign in / Sign up

Export Citation Format

Share Document