Variability of the hydrological characteristics of the Eastern Mediterranean over the last decade

2021 ◽  
Author(s):  
Claude Estournel ◽  
Patrick Marsaleix ◽  
Caroline Ulses
Keyword(s):  
Water Mass ◽  
Eastern Mediterranean ◽  
Temporal Distribution ◽  
Aegean Sea ◽  
Eastern Basin ◽  
Mesoscale Structures ◽  
Levantine Basin ◽  
Water Mass Formation ◽  
Intermediate Waters ◽  
Argo Profiles

<p><span>A hydrodynamic simulation is carried out over the entire Mediterranean basin at a resolution of 3 to 4 km and a duration of about 10 years (2011-2020). The results are systematically evaluated using Argo profiles focusing on the spatial distribution of water mass properties along their path, the main mesoscale structures, the mean vertical temperature and salinity profiles by sub-basins as well as their "pseudo temporal evolution" biased by the variability of the spatial and temporal distribution of Argo observations.</span></p><p><span>The simulation has generally very low mean biases (of the order of 0.01 for salinity) and correlations on the monthly time series reconstructed from the observations, of the order of 0.9 at the scale of the eastern basin, both in surface waters and at 200 m in intermediate waters. </span></p><p><span>The evolution of salinity over the decade is then analyzed from the simulation. Particular attention is paid to the main basins of water mass formation, the Adriatic, the Levantine basin and the South Aegean Sea. The factors driving this evolution are analyzed in each of these basins. The propagation of the changes from these formation areas to the entire eastern basin is then examined, with a particular focus on the intermediate waters. </span></p>

scholarly journals Detection and Characterisation of Eemian Marine Tephra Layers within the Sapropel S5 Sediments of the Aegean and Levantine Seas

Quaternary ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 6
Author(s):  
Christopher Satow ◽  
Katharine M. Grant ◽  
Sabine Wulf ◽  
Hartmut Schulz ◽  
Addison Mallon ◽  
...  
Keyword(s):  
Major Element ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Interglacial Period ◽  
Last Interglacial ◽  
Proxy Records ◽  
Last Interglacial Period ◽  
Levantine Basin ◽  
History Of ◽  
Tephra Layers

The Eemian was the last interglacial period (~130 to 115 ka BP) to precede the current interglacial. In Eastern Mediterranean marine sediments, it is marked by a well-developed and organic-rich “sapropel” layer (S5), which is thought to reflect an intensification and northward migration of the African monsoon rain belt over orbital timescales. However, despite the importance of these sediments, very little proxy-independent stratigraphic information is available to enable rigorous correlation of these sediments across the region. This paper presents the first detailed study of visible and non-visible (cryptotephra) layers found within these sediments at three marine coring sites: ODP Site 967B (Levantine Basin), KL51 (South East of Crete) and LC21 (Southern Aegean Sea). Major element analyses of the glass component were used to distinguish four distinct tephra events of Santorini (e.g., Vourvoulos eruption) and possible Anatolian provenance occurring during the formation of S5. Interpolation of core chronologies provides provisional eruption ages for the uppermost tephra (unknown Santorini, 121.8 ± 2.9 ka) and lowermost tephra (Anatolia or Kos/Yali/Nisyros, 126.4 ± 2.9 ka). These newly characterised tephra deposits have also been set into the regional tephrostratigraphy to illustrate the potential to precisely synchronise marine proxy records with their terrestrial counterparts, and also contribute to the establishment of a more detailed volcanic history of the Eastern Mediterranean.

scholarly journals Thermohaline properties in the Eastern Mediterranean in the last three decades: is the basin returning to the pre-EMT situation?

2014 ◽  
Vol 11 (1) ◽  
pp. 391-423 ◽  
Author(s):  
V. Cardin ◽  
G. Civitarese ◽  
D. Hainbucher ◽  
M. Bensi ◽  
A. Rubino
Keyword(s):  
Deep Water ◽  
Water Mass ◽  
Deep Layer ◽  
Eastern Mediterranean ◽  
Salt Content ◽  
Intermediate Water ◽  
Levantine Basin ◽  
Mass Properties ◽  
Wide Scale ◽  
East West

Abstract. We present temperature, salinity and oxygen data collected during the M84/3 and P414 cruises in April and June 2011 on a basin-wide scale to determine the ongoing oceanographic characteristics in the Eastern Mediterranean (EM). The east–west transect through the EM sampled during the M84/3 cruise together with data gained on previous cruises over the period 1987–2011 are analysed in terms of regional aspects of the evolution of water mass properties and heat and salt content variation. The present state of the EM basin is also evaluated in the context of the evolution of the Eastern Mediterranean Transient (EMT). From this analysis we can infer that the state of the basin is still far from achieving the pre-EMT conditions. Indeed, the 2011 oceanographic conditions of the deep layer of the central Ionian lie between the thermohaline characteristics of the EMT and the pre-EMT phase, indicating a possible slow return towards the latter. In addition, the thermohaline properties of the Adriatic Deep Water are still in line (warmer and saltier) as when it restarted to produce dense waters after the EMT. Special attention is given to the variability of thermohaline properties of the Levantine Intermediate Water and Adriatic Deep Water in three main areas: the Cretan, the central Levantine and the central Ionian Seas. Finally, this study evidences the relationships among the hydrological property distributions of the upper-layer in the Levantine basin and the circulation regime in the Ionian.

scholarly journals Aegean Sea Water Masses during the Early Stages of the Eastern Mediterranean Climatic Transient (1988–90)

2006 ◽  
Vol 36 (9) ◽  
pp. 1841-1859 ◽  
Author(s):  
I. Gertman ◽  
N. Pinardi ◽  
Y. Popov ◽  
A. Hecht
Keyword(s):  
Surface Water ◽  
Deep Water ◽  
Water Mass ◽  
Sea Water ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Water Masses ◽  
Intermediate Water ◽  
Central Basin ◽  
Cretan Sea

Abstract The Aegean water masses and circulation structure are studied via two large-scale surveys performed during the late winters of 1988 and 1990 by the R/V Yakov Gakkel of the former Soviet Union. The analysis of these data sheds light on the mechanisms of water mass formation in the Aegean Sea that triggered the outflow of Cretan Deep Water (CDW) from the Cretan Sea into the abyssal basins of the eastern Mediterranean Sea (the so-called Eastern Mediterranean Transient). It is found that the central Aegean Basin is the site of the formation of Aegean Intermediate Water, which slides southward and, depending on their density, renews either the intermediate or the deep water of the Cretan Sea. During the winter of 1988, the Cretan Sea waters were renewed mainly at intermediate levels, while during the winter of 1990 it was mainly the volume of CDW that increased. This Aegean water mass redistribution and formation process in 1990 differed from that in 1988 in two major aspects: (i) during the winter of 1990 the position of the front between the Black Sea Water and the Levantine Surface Water was displaced farther north than during the winter of 1988 and (ii) heavier waters were formed in 1990 as a result of enhanced lateral advection of salty Levantine Surface Water that enriched the intermediate waters with salt. In 1990 the 29.2 isopycnal rose to the surface of the central basin and a large volume of CDW filled the Cretan Basin. It is found that, already in 1988, the 29.2 isopycnal surface, which we assume is the lowest density of the CDW, was shallower than the Kassos Strait sill and thus CDW egressed into the Eastern Mediterranean.

Modelling the water mass circulation in the Aegean Sea. Part I: wind stresses, thermal and haline fluxes

1994 ◽  
Vol 12 (8) ◽  
pp. 794-807 ◽  
Author(s):  
I. A. Valioulis ◽  
Y. N. Krestenitis
Keyword(s):  
Experimental Evidence ◽  
Black Sea ◽  
Computer Model ◽  
Seasonal Variations ◽  
Water Mass ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Water Fluxes ◽  
Physical Processes ◽  
Mass Circulation

Abstract. The aim of this work is to develop a computer model capable of simulating the water mass circulation in the Aegean Sea. There is historical, phenomenological and recent experimental evidence of important hydrographical features whose causes have been variably identified as the highly complex bathymetry, the extreme seasonal variations in temperature, the considerable fresh water fluxes, and the large gradients in salinity or temperature across neighbouring water masses (Black Sea and Eastern Mediterranean). In the approach taken here, physical processes are introduced into the model one by one. This method reveals the parameters responsible for permanent and seasonal features of the Aegean Sea circulation. In the first part of the work reported herein, wind-induced circulation appears to be seasonally invariant. This yearly pattern is overcome by the inclusion of baroclinicity in the model in the form of surface thermohaline fluxes. The model shows an intricate pattern of sub-basin gyres and locally strong currents, permanent or seasonal, in accord with the experimental evidence.

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