Estimating vertical mixing in the deep north Aegean Sea using argo data corrected for conductivity sensor drift

Zervakis, Vassilis; Krauzig, Naomi; Tragou, Elina; Kunze, Eric

doi:10.1016/j.dsr.2019.103144

Cited by 7 publications

(3 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Based on the slopes of the density time-series, three significantly different periods can be identified: The short and episodic dense-water formation events (namely in the winters of 1987, 1992, 1993 and smaller episodes in 2008 and 2012, and a gradual increase of density after 2008), the periods of stagnation (characterized by decreasing densities), and the steady-state periods (where the density remains more of less constant). The periods of stagnation correspond to a dynamical balance between the rate of buoyancy gain in the deep basin and the downward vertical buoyancy flux through the interface between intermediate and deep waters [69,70]. The periods of steady state usually take place after prolonged stagnation periods have led to gradual homogeneity between the intermediate and deep layers, and, thus, the turbulent fluxes across the boundary are minimal.…”

Section: Discussionmentioning

confidence: 99%

A High-Resolution Numerical Model of the North Aegean Sea Aimed at Climatological Studies

Mamoutos

Potiris

Tragou

et al. 2021

JMSE

View full text Add to dashboard Cite

A new, high-resolution model for the northern part of the Aegean Sea, aimed primarily at climatological research (relaxation and data assimilation-free climate simulations), is hereby presented, along with the results of a 28-year-long simulation covering the period from 1986 to 2013. The model applied is the Regional Ocean Modelling System (ROMS). A significant improvement over previous models of the Aegean introduced in this work is the replacement of parameterizations of the Dardanelles exchange by a fully three-dimensional simulation of the flow in the Strait. The incorporation of part of the Marmara Sea in the model domain enables the interaction with other regional climate simulations, thus allowing climatic variability of the exchange of the Mediterranean and Black Seas. An extensive validation is carried out comparing the model output with all the available observations from several different platforms, i.e., satellite sea surface temperature and height, T/S profiles from R/V ships, and HF radar surface currents velocity. We focus on the model’s ability to reproduce, to some extent, the distinct thermohaline features and circulation patterns that characterize this specific area of the Mediterranean Sea. Our findings, after comparing simulation results with all the available observations, revealed the model’s sufficiency to simulate very adequately the complex hydrology of the North Aegean Sea, and the model’s ability to reproduce incidents of deep-water formation that took place in the region in previous decades during the Eastern Mediterranean Transient (EMT).

show abstract

Section: Discussionmentioning

confidence: 99%

A High-Resolution Numerical Model of the North Aegean Sea Aimed at Climatological Studies

Mamoutos

Potiris

Tragou

et al. 2021

JMSE

View full text Add to dashboard Cite

show abstract

“…Water with a density of 29.15 kg m −3 filled the deep pit of the Lesvos Basin below 500 m during November 2021. The highest density inside the pit were recorded on 19 January about two weeks before the surfacing of the 29 kg m −3 isopycnal, which had dropped to 29.1 kg m −3 , thereby indicating a downward buoyancy flux that is typical of the stagnation periods in deep basins [153] during that period. The near-surface density recorded by float 298 after 19 January, while outside the pit but still in the southern Lesvos region, never exceeded the 29.1 kg m −3 threshold.…”

Section: Observations From Argo Floats 297 and 298mentioning

confidence: 96%

Dense Water Formation in the North–Central Aegean Sea during Winter 2021–2022

Potiris,

Mamoutos,

Tragou

et al. 2024

JMSE

View full text Add to dashboard Cite

The evolution and drivers of dense water formation (DWF) in the North–Central Aegean Sea (NCAeg) during winter 2021–2022 are studied using observations from two Argo floats and the output of an operational data-assimilating model. Dense water with σθ>29.1 kgm−3 was produced over most of the NCAeg, except for the northeastern part covered by Black Sea water (BSW), where the maximum surface density was <29 kgm−3. The highest density waters were produced over the central and southern parts of the Lemnos Plateau and in the shallow coastal areas between Chios Island and the Edremit Gulf. Atmospherically driven transformation to the east of Lesvos Island resulted in the production of waters with anomalously high density and salinity, which flowed inside Skiros Basin, thus partly explaining its historically higher density and salinity compared to the rest of the NCAeg subbasins. The Skiros and Athos Basins were ventilated down to σθ∼29.35 kgm−3 horizons. The 29.1 kgm−3 isopycnal rose by ∼200 m, and the 29.25 kgm−3 isopycnal overflowed above the ∼400 m sill depth filling the southern depressions of the NCAeg. Combining data from Argo floats, vessel casts, gliders, and a fixed-point observatory, the dense water produced in the NCAeg was observed spreading in the deep layer of the Central Cretan Sea for at least one and a half years after the formation. The cyclonic circulation of the newly formed water in the NCAeg has been observed directly for the first time using deep-drifting floats. The Eastern Mediterranean warming and salinification signal has propagated below the NCAeg sill depth. The winter average buoyancy loss was comparable to that of the peak of the Eastern Mediterranean transient (EMT) and other known years of DWF in the NCAeg; however, the high temperature of the upper layers due to long-term warming prevented the widespread formation of denser water.

show abstract

“…Temperature conditions seem to contribute and favor this pattern (Badran, 2001;Corsini-Foka et al, 2010). The species has not yet been established in the North Aegean Sea probably due to the winter isotherm (from Evvoia to Chios) of 15°C and the prevailing colder waters in the northern parts of the Aegean (Zervakis et al, 2019). In recent years, however, the isotherm seems to be changing its location and Lessepsian migrants, including E. golanii, are being recorded in northern parts of the Aegean Sea, signaling possible spreads (Corsini-Foka et al, 2010).…”

Section: Risk Of Establishmentmentioning

confidence: 97%

Risk assessment of Golani’s round herring (Etrumeus golanii) in the Greek seas (northeastern Mediterranean Sea)

Keramidas,

Tsikliras,

Zenetos

et al. 2023

Front. Mar. Sci.

View full text Add to dashboard Cite

Greek waters are the recipient of several alien species, mainly through natural dispersal following invasion and establishment of non-indigenous species (NIS) in neighboring areas, making their monitoring and mitigating their effects of paramount importance. The European Union legislation framework toward alien species invasions considers risk assessments as the top of the spear for a first assessment of NIS and their potential to become invasive or not. The Union List has already included top priority species, with very few marine species. Golani’s round herring (Etrumeus golanii) is a species of round herrings in the family Dussumieriidae, a Lessepsian migrant and belonging to a group of NIS in the Mediterranean basin that are less studied. Its distribution range is mainly limited in the southeastern Mediterranean Sea, while in the Greek seas, it has not yet been observed in the north Aegean and Ionian seas, probably due to temperature and oceanographical reasons. Its presence in the basin is recorded by commercial fisheries landings in several countries (especially purse-seiners), indicating a potentially positive effect on commercial fisheries. A risk assessment of E. golanii in Greek waters was carried out in this work, based on the Risk Assessment Scheme developed by the GB Non-Native Species Secretariat (GB Non-Native Risk Assessment—GBNNRA). An overall semi-quantitative summary of risk, in terms of likelihood of events and magnitude of impacts, was facilitated for several attributors, including confidence levels for each one. The assessment highlighted a very likely possibility of introduction in the Greek seas from neighboring countries, as well as successful establishments of populations with high confidence levels. A moderate magnitude of impact regarding its further spread was deemed, while a minor one was indicated in terms of native species pressure and a minimal one in terms of economic costs and public health. Overall, E. golanii was not characterized as an invasive alien species (IAS) and local communities could benefit from its presence (commercial fisheries); however, further studies focusing on its reproduction and spawning grounds should be implemented.

show abstract

Estimating vertical mixing in the deep north Aegean Sea using argo data corrected for conductivity sensor drift

Cited by 7 publications

References 66 publications

A High-Resolution Numerical Model of the North Aegean Sea Aimed at Climatological Studies

A High-Resolution Numerical Model of the North Aegean Sea Aimed at Climatological Studies

Dense Water Formation in the North–Central Aegean Sea during Winter 2021–2022

Risk assessment of Golani’s round herring (Etrumeus golanii) in the Greek seas (northeastern Mediterranean Sea)

Contact Info

Product

Resources

About