Temporal evolution of the water mass properties during the Eastern Mediterranean transient (EMT) in the Aegean Sea

2010 ◽  
Vol 115 (C10) ◽  
Author(s):  
Erdem Sayın ◽  
Şükrü T. Beşiktepe
Keyword(s):  
Water Mass ◽  
Temporal Evolution ◽  
Eastern Mediterranean ◽  
Aegean Sea ◽  
Mass Properties

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 Hydrographic situation during cruise M84/3 and P414 (spring 2011) in the Mediterranean Sea

2013 ◽  
Vol 10 (6) ◽  
pp. 2399-2432 ◽  
Author(s):  
D. Hainbucher ◽  
A. Rubino ◽  
V. Cardin ◽  
T. Tanhua ◽  
K. Schroeder ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Large Scale ◽  
Water Mass ◽  
Eastern Mediterranean ◽  
Physical Parameters ◽  
Strait Of Gibraltar ◽  
Mass Properties ◽  
The Mediterranean ◽  
Geostrophic Velocities ◽  
Lebanese Coast

Abstract. Hydrography and large scale circulation observed in the Mediterranean Sea during the M84/3 and P414 cruises (April and June 2011, respectively) are presented. In contrast to most of the recent expeditions, which were limited to special areas of the basin, these two cruises, especially the M84/3, offered the opportunity of delineating a quasi-synoptic picture of the distribution of the relevant physical parameters through the whole Mediterranean. A section was observed from the Lebanese coast up to the Strait of Gibraltar. The focus of our analysis are the water mass properties, also in the context of the recently observed variability, and a comparison between the velocity fields observed using a vessel-mounted ADCP and those calculated from the observed density fields. Overall, a distribution of temperature, salinity, and geostrophic velocities emerges, which seems far from that observed before the beginning of the so-called "Eastern Mediterranean Transient", a major climatic shift in the hydrography and circulation of the Mediterranean Sea occurred at the end of 1980s. Here, our focus is a discussion of the observed water mass properties analysed through T–S diagrams and through an Optimum Multiparameter (OMP) analysis. Additionally, ADCP velocities are compared to geostrophic calculations.

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.

scholarly journals Temperature and salinity variability in the Greek Seas based on POSEIDON stations time series: preliminary results

2013 ◽  
Vol 14 (3) ◽  
pp. 5 ◽  
Author(s):  
D. VELAORAS ◽  
D. KASSIS ◽  
L. PERIVOLIOTIS ◽  
P. PAGONIS ◽  
A. HONDRONASIOS ◽  
...  
Keyword(s):  
Time Series ◽  
Water Mass ◽  
Sea Water ◽  
Eastern Mediterranean ◽  
Winter Season ◽  
Aegean Sea ◽  
Intermediate Water ◽  
Intermediate Water Mass ◽  
North Aegean Sea ◽  
Cretan Sea

Temperature and salinity time series provided by three POSEIDON monitoring stations (buoys) are examined in order to study the seasonal and interannual variability of the water mass characteristics. The sites at Athos (North Aegean Sea), E1M3A (Central Cretan Sea) and Pylos (Eastern Ionian Sea) were chosen, as these buoys provide measurements at various depths, while they represent 3 major basins respectively. The study of the T and S characteristics reveals important seasonal changes and highlights the particular characteristics of each basin. Dense water production in the Northern Aegean is found to be hindered by the presence of the surface Black Sea Water (BSW) mass. On the other hand, the intermediate water mass in the Cretan Sea is shown to be ventilated during the winter season. A significant temperature and salinity increase has been monitored over both the Central Cretan and Eastern Ionian Seas starting from the middle of 2008 and 2009 respectively. This could possibly be attributed to changes in the intermediate water masses of the Eastern Mediterranean, without ruling out the possibility of water mass exchanges between the two basins.

Water mass properties and dynamic conditions of the Eastern Mediterranean in June 2007

2012 ◽  
Vol 104 ◽  
pp. 59-79 ◽  
Author(s):  
Vedrana Kovačević ◽  
Beniamino Bruno Manca ◽  
Laura Ursella ◽  
Katrin Schroeder ◽  
Stefano Cozzi ◽  
...  
Keyword(s):  
Water Mass ◽  
Eastern Mediterranean ◽  
Dynamic Conditions ◽  
Mass Properties

scholarly journals Long-Term Changes in the Water Mass Properties in the Balearic Channels Over the Period 1996–2019

2021 ◽  
Vol 8 ◽  
Author(s):  
Manuel Vargas-Yáñez ◽  
Mélanie Juza ◽  
M. Carmen García-Martínez ◽  
Francina Moya ◽  
Rosa Balbín ◽  
...  
Keyword(s):  
Water Column ◽  
Water Mass ◽  
Eastern Mediterranean ◽  
Western Mediterranean ◽  
Intermediate Water ◽  
Deep Waters ◽  
Mass Properties ◽  
Long Term Changes ◽  
Intermediate Waters

The analysis of a 24-year time series of Conductivity-Temperature-Depth (CTD) casts collected in the Balearic Channels (1996–2019) has allowed detecting and quantifying long-term changes in water mass properties in the Western Mediterranean. For the complete period, the intermediate waters have experienced warming and salting at rates of 1.4°C/100yr and 0.3–0.6/100yr for the Western Intermediate Water, and 1°C/100yr and 0.3–0.4/100yr for the Levantine Intermediate Water. The density of these two water masses has not changed. The deep waters, defined as those denser than 29.1 kg/m3, showed positive trends in temperature, salinity, and density (0.8°C/100yr, 0.2/100yr, and 0.02 kg.m–3/100yr, respectively). The high temporal variability of the upper layer makes the detection of long-term changes more difficult. Nevertheless, combining CTD data with temperature data from the oceanographic station at L’Estartit and simulated data from the NCEP/NCAR reanalysis, it can be established that the Atlantic Water increased its temperature at a rate of 2.1–2.8°C/100yr and likely its salinity at a rate of 0.6/100yr. The water column absorbed heat at a rate equivalent to 1–1.2 W/m2. All these trends are much higher than those reported in previous works (more than double in some cases). The warming of the water column produced an increase in the thermosteric component of sea level. However, this increase was compensated by the decrease in the halosteric component. Besides these changes, other alterations related to the Western Mediterranean Transition have been observed over shorter periods. The temperature and salinity of the intermediate waters increased before the winter of 2004/2005 and then the temperature and salinity of the deep waters increased dramatically in 2005. The density of the deep water reached values unprecedented before 2005. Deep and intermediate waters were uplifted by the presence of such dense deep waters. The arrival of warmer and saltier intermediate waters from the Eastern Mediterranean is also observed, mainly after 2010.

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>

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