scholarly journals Tracking the Serpentinite Feet of the Mediterranean Salt Giant

Geosciences ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 352 ◽  
Author(s):  
Vittorio Scribano ◽  
Serafina Carbone ◽  
Fabio Manuella
Keyword(s):  
Central Area ◽  
Mediterranean Area ◽  
Oceanic Lithosphere ◽  
Sea Salt ◽  
Ultramafic Rocks ◽  
Seismic Profiles ◽  
Western Atlantic ◽  
Sea Bottom ◽  
Salt Deposits ◽  
The Mediterranean

Interpretation of seismic profiles and results of scientific drillings in the Mediterranean subseafloor provided indication of gigantic salt deposits which rarely crop out on land, such as in Sicily. The salt giants were ascribed to the desiccation, driven by the solar energy, of the entire basin. Nevertheless, the evaporite model hardly explains deep-sea salt deposits. This paper considers a different hypothesis suggesting that seawater reached NaCl saturation during serpentinization of ultramafic rocks. Solid salts and brine pockets were buried within the serpentinite bodies being later (e.g., in the Messinian) released, due to serpentinite breakdown, and discharged at seafloor as hydrothermal heavy brines. Therefore, sea-bottom layers of brine at gypsum and halite saturation were formed. The model is applicable to the Mediterranean area since geophysical data revealed relicts of an aged (hence serpentinized) oceanic lithosphere, of Tethyan affinity, both in its western “Atlantic” extension (Gulf of Cádiz) and in eastern basins, and xenoliths from Hyblean diatremes (Sicily) provided evidence of buried serpentinites in the central area. In addition, the buoyant behavior of muddled serpentinite and salts (and hydrocarbons) gave rise to many composite diapirs throughout the Mediterranean area. Thus, the Mediterranean “salt giant” consists of several independent geobodies of serpentinite and salts.

scholarly journals Source contributions to 2012 summertime aerosols in the Euro-Mediterranean region

2015 ◽  
Vol 15 (14) ◽  
pp. 8013-8036 ◽  
Author(s):  
G. Rea ◽  
S. Turquety ◽  
L. Menut ◽  
R. Briant ◽  
S. Mailler ◽  
...  
Keyword(s):  
Mineral Dust ◽  
Mediterranean Area ◽  
Sea Salt ◽  
Anthropogenic Sources ◽  
Anthropogenic Emissions ◽  
The European Union ◽  
Natural Sources ◽  
Fire Emissions ◽  
Relative Contribution ◽  
The Mediterranean

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 whether European pollution limits are exceeded and, if so, whether 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 on a 50 km resolution domain (from −10° W to 40° E and from 30° N to 55° N): one simulation with all sources (reference) and all others with one source removed. The reference simulation is compared to data from the AirBase network and two ChArMEx stations, and from the AERONET network and the MODIS satellite instrument, to quantify the ability of the model to reproduce the observations. It is shown that the correlation ranges from 0.19 to 0.57 for surface particulate matter and from 0.35 to 0.75 for AOD. For the summer of 2012, the model shows that the region 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, on average, during the period near local sources. Sea salt mainly contributes 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 daily exceedances of the European Union limit of 50 μg m−3 for PM10 (over the stations), and for the number of daily exceedances of the WHO recommendation for PM2.5 (25 μg m−3), over the western part of Europe and the central north. This number is generally overestimated by the model, particularly in the northern part of the domain, but exceedances are captured at the right time. Optimized contributions are computed with the observations, by subtracting the background bias at each station and the specific peak biases from the considered sources. These optimized contributions show that if natural sources such as mineral dust and fire events are particularly difficult to estimate, they were responsible exclusively for 35.9 and 0.7 %, respectively, of the exceedances for PM10 during the summer of 2012. The PM25 recommendation of 25 μg m−3 is exceeded in 21.1 % of the cases because of anthropogenic sources exclusively and in 0.02 % because of fires. The other exceedances are induced by a mixed contribution between mainly mineral dust (49.5–67 % for PM10 exceedance contributions, 4.4–13.8 % for PM2.5), anthropogenic sources (14.9–24.2 % and 46.3–80.6 %), biogenic sources (4.1–15.7 % and 12.6–30 %) and fires (2.2–7.2 % and 1.6–12.4 %).

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

2010 ◽  
Vol 10 (12) ◽  
pp. 30999-31038
Author(s):  
P. Jimenez-Guerrero ◽  
O. Jorba ◽  
M. T. Pay ◽  
J. P. Montavez ◽  
S. Jerez ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Mediterranean Basin ◽  
Surface Wind ◽  
Mediterranean Area ◽  
Sea Salt ◽  
Target Area ◽  
Transport Models ◽  
The Mediterranean ◽  
The Mediterranean Basin

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.

scholarly journals Source contributions to 2012 summertime aerosols in the Euro-Mediterranean region

2015 ◽  
Vol 15 (6) ◽  
pp. 8191-8242 ◽  
Author(s):  
G. Rea ◽  
S. Turquety ◽  
L. Menut ◽  
R. Briant ◽  
S. Mailler ◽  
...  
Keyword(s):  
Mediterranean Basin ◽  
Mineral Dust ◽  
Mediterranean Area ◽  
Sea Salt ◽  
Anthropogenic Emissions ◽  
The European Union ◽  
Natural Sources ◽  
Fire Emissions ◽  
The Mediterranean ◽  
The Impact

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).

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 ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Wet Deposition ◽  
Mediterranean Basin ◽  
Mediterranean Area ◽  
Sea Salt ◽  
Target Area ◽  
Transport Models ◽  
Sea Salt Aerosol ◽  
The Mediterranean ◽  
The Mediterranean Basin

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.

Spatial Distribution of Pre-Warm Front Rainfall in the Mediterranean Area

1988 ◽  
Vol 19 (1) ◽  
pp. 53-64 ◽  
Author(s):  
C. Corradini ◽  
F. Melone
Keyword(s):  
Mediterranean Area ◽  
Compact Structure ◽  
Large Variability ◽  
Air Mass ◽  
Orographic Effects ◽  
Warm Front ◽  
Average Rainfall ◽  
Convective Motions ◽  
Rainfall Type ◽  
The Mediterranean

Evidence is given of the distribution of pre-warm front rainfall at the meso-γ scale, together with a discussion of the main mechanisms producing this variability. An inland region in the Mediterranean area is considered. The selected rainfall type is commonly considered the most regular inasmuch as it is usually unaffected by extended convective motions. Despite this, within a storm a large variability in space was observed. For 90% of measurements, the typical deviations from the area-average total depth ranged from - 40 to 60 % and the storm ensemble-average rainfall rate over an hilly zone was 60 % greater than that in a contiguous low-land zone generally placed upwind. This variability is largely explained in terms of forced uplift of air mass over an envelope type orography. For a few storms smaller orographic effects were found in locations influenced by an orography with higher slopes and elevations. This feature is ascribed to the compact structure of these mountains which probably determines a deflection of air mass in the boundary layer. The importance of this type of analysis in the hydrological practice is also emphasized.

Warfare and Environment in the Ancient World

2013 ◽  
pp. 127-140
Author(s):  
J. Donald Hughes
Keyword(s):  
Natural Environment ◽  
Armed Conflict ◽  
Near East ◽  
Mediterranean Area ◽  
Ancient World ◽  
Direct Effects ◽  
Environmental Properties ◽  
The Mediterranean ◽  
Ancient Warfare ◽  
The Military

This chapter deals with ancient warfare and the environment. Hunting was often been considered as a form of warfare, and art frequently portrayed humans in battle with animals. Armed conflict had its direct influences on the environment. Along with damage to settled agriculture, warfare had affected other lands such as pastures, brush lands, and forests. It is noted that birds, pigs, bears, rodents, snakes, bees, wasps, scorpions, beetles, assassin bugs, and jellyfish have been employed as weaponized animals in ancient warfare, which, in the Mediterranean area and Near East, had vital environmental properties. The direct effects of battle have been shown by ancient historians, but just as important were the influences of the military-oriented organization of societies on the natural environment and resources.

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