Venerid bivalve Venus verrucosa as a high-resolution archive of seawater temperature in the Mediterranean Sea

Between 19 and 22 January 2014, a baroclinic wave moving eastward from the Atlantic Ocean generated a cut-off low over the Strait of Gibraltar and was responsible for the subsequent intensification of an extra-tropical cyclone. This system exhibited tropical-like features in the following stages of its life cycle and remained active for approximately 80 h, moving along the Mediterranean Sea from west to east, eventually reaching the Adriatic Sea. Two different modeling approaches, which are comparable in terms of computational cost, are analyzed here to represent the cyclone evolution. First, a multi-physics ensemble using different microphysics and turbulence parameterization schemes available in the WRF (weather research and forecasting) model is employed. Second, the COAWST (coupled ocean–atmosphere wave sediment transport modeling system) suite, including WRF as an atmospheric model, ROMS (regional ocean modeling system) as an ocean model, and SWAN (simulating waves in nearshore) as a wave model, is used. The advantage of using a coupled modeling system is evaluated taking into account air–sea interaction processes at growing levels of complexity. First, a high-resolution sea surface temperature (SST) field, updated every 6 h, is used to force a WRF model stand-alone atmospheric simulation. Later, a two-way atmosphere–ocean coupled configuration is employed using COAWST, where SST is updated using consistent sea surface fluxes in the atmospheric and ocean models. Results show that a 1D ocean model is able to reproduce the evolution of the cyclone rather well, given a high-resolution initial SST field produced by ROMS after a long spin-up time. Additionally, coupled simulations reproduce more accurate (less intense) sea surface heat fluxes and a cyclone track and intensity, compared with a multi-physics ensemble of standalone atmospheric simulations.

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High-resolution nested model simulations of the climatological circulation in the southeastern Mediterranean Sea

Annales Geophysicae ◽

10.5194/angeo-21-267-2003 ◽

2003 ◽

Vol 21 (1) ◽

pp. 267-280 ◽

Cited By ~ 16

Author(s):

S. Brenner

Keyword(s):

High Resolution ◽

Continental Shelf ◽

Mediterranean Sea ◽

Seasonal Cycle ◽

Internal Variability ◽

Ocean Model ◽

Heat Fluxes ◽

Intermediate Model ◽

Grid Model ◽

The Mediterranean

Abstract. As part of the Mediterranean Forecasting System Pilot Project (MFSPP) we have implemented a high-resolution (2 km horizontal grid, 30 sigma levels) version of the Princeton Ocean Model for the southeastern corner of the Mediterranean Sea. The domain extends 200 km offshore and includes the continental shelf and slope, and part of the open sea. The model is nested in an intermediate resolution (5.5 km grid) model that covers the entire Levantine, Ionian, and Aegean Sea. The nesting is one way so that velocity, temperature, and salinity along the boundaries are interpolated from the relevant intermediate model variables. An integral constraint is applied so that the net mass flux across the open boundaries is identical to the net flux in the intermediate model. The model is integrated for three perpetual years with surface forcing specified from monthly mean climatological wind stress and heat fluxes. The model is stable and spins up within the first year to produce a repeating seasonal cycle throughout the three-year integration period. While there is some internal variability evident in the results, it is clear that, due to the relatively small domain, the results are strongly influenced by the imposed lateral boundary conditions. The results closely follow the simulation of the intermediate model. The main improvement is in the simulation over the narrow shelf region, which is not adequately resolved by the coarser grid model. Comparisons with direct current measurements over the shelf and slope show reasonable agreement despite the limitations of the climatological forcing. The model correctly simulates the direction and the typical speeds of the flow over the shelf and slope, but has difficulty properly re-producing the seasonal cycle in the speed.Key words. Oceanography: general (continental shelf processes; numerical modelling; ocean prediction)

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A high resolution reanalysis for the Mediterranean Sea

10.5194/egusphere-egu21-11420 ◽

2021 ◽

Author(s):

Romain Escudier ◽

Emanuela Clementi ◽

Mohamed Omar ◽

Andrea Cipollone ◽

Jenny Pistoia ◽

...

Keyword(s):

High Resolution ◽

Mediterranean Sea ◽

Large Scale ◽

Thermohaline Circulation ◽

Deep Convection ◽

Horizontal Resolution ◽

Continuous Increase ◽

The Past ◽

The Mediterranean

In order to be able to predict the future ocean climate and weather, it is crucial to understand what happened in the past and the mechanisms responsible for the ocean variability. This is particularly true in a complex area such as the Mediterranean Sea with diverse dynamics such as deep convection and thermohaline circulation or coastal hydrodynamics. To this end, effective tools are reanalyses or reconstructions of the past ocean state.&#160;Here we present a new physical reanalysis of the Mediterranean Sea at high resolution, developed in the Copernicus Marine Environment Monitoring Service (CMEMS) framework. The hydrodynamic model is based on the Nucleus for European Modelling of the Ocean (NEMO) combined with a variational data assimilation scheme (OceanVar).The model has a horizontal resolution of 1/24&#176;&#160;and 141 vertical z* levels and provides daily and monthly 3D values of temperature, salinity, sea level and currents. Hourly ECMWF ERA-5 atmospheric fields force the model and daily boundary conditions in the Atlantic are taken from the global CMCC C-GLORS reanalysis. 39 rivers model the freshwater input to the basin plus the Dardanelles. The reanalysis covers 33-years, initialized from SeaDataNet climatology in January 1985, getting to a nominal state after a two-years spin-up and ending in 2019. In-situ data from CTD, ARGO floats and XBT are assimilated into the model in combination with satellite altimetry data.This reanalysis has been validated and assessed through comparison to in-situ and satellite observations as well as literature climatologies. The results show an overall improvement of the skill and a better representation of the main dynamics of the region compared to the previous, lower resolution (1/16&#176;) reanalysis. Temperature and salinity RMSE is decreased by respectively 12% and 20%. The deeper biases in salinity of the previous version are corrected and the new reanalysis present a better representation of the deep convection in the Gulf of Lion. Climate signals show continuous increase of the temperature due to climate change but also in salinity.The new reanalysis will allow the study of physical processes at multi-scales, from the large scale to the transient small mesoscale structures.

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Investigation of sea breeze and foehn in the Dead Sea valley with remote sensing observations and WRF model simulations

10.5194/egusphere-egu2020-1708 ◽

2020 ◽

Author(s):

Dorita Rostkier-Edelstein ◽

Pavel Kunin ◽

Pinhas Alpert

Keyword(s):

Remote Sensing ◽

High Resolution ◽

Mediterranean Sea ◽

Sea Breeze ◽

Dead Sea ◽

Modeling Tools ◽

Model Simulations ◽

Single Location ◽

The Mediterranean ◽

The Dead

The atmospheric dynamics in the Dead Sea Valley has been studied for decades. However, the studies relied mostly on surface observations and simple coarse-model simulations, insufficient to elucidate the complex flow in the area. In this seminar I will present a first study using high resolution (temporal and spatial) and sophisticate both, measurements and modeling tools. We focused on afternoon hours during summer time, when the Mediterranean Sea breeze penetrates into the Dead Sea Valley and sudden changes of wind, temperature and humidity occur in the valley.An intense observations period in the area, including ground-based remote sensing and in-situ observations, took place during August and November 2014. The measurements were conducted as part of the Virtual Institute DEad SEa Research Venue (DESERVE) project using the KITcube profiling instruments (wind lidars, radiometer and soundings) along with surface Energy Balance Station. These observations enabled analysis of the vertical profile of the atmosphere at one single location at the foothills of Masada, about 1 km west of the Dead Sea shore.High resolution (1.1 km grid size) model simulations were conducted using the Advanced Research Weather version of the Weather Forecast and Research mesoscale model (WRF). The simulations enabled analysis of the 3D flow at the Dead Sea Valley, information not provided by the observations at a single location. Sensitivity tests were run to determine the best model configuration for this study.Our study shows that foehn develops in the lee side of the Judean Mountains and Dead Sea Valley in the afternoon hours when the Mediterranean Sea breeze reaches the area. The characteristics of the Mediterranean Sea breeze penetration into the valley and of the foehn (e.g. their depth) and the impact they have on the boundary layer flow in the Dead Sea Valley (e.g. sudden changes in temperature, humidity and wind) are conditioned to the daily synoptic and mesosocale conditions. In the synoptic scale, the depth of the seasonal pressure trough at sea level and the height of inversion layers play a significant role in determining the breeze and foehn characteristics. In the mesoscale, the intensity of the Dead Sea breeze and the humidity brought by it determines the outcomes at the time of Mediterranean Sea breeze penetration and foehn development. Dynamically, the foehn is associated with a hydraulic jump.Hypothetical model simulations with modified terrain and with warmer Mediterranean Sea surface temperature were conducted to reveal the relative contribution of each of these factors and of their synergism on the observed phenomena. The information provided by the factor separation study can be useful in future climate projections, when a warmer Mediterranean Sea is expected.The forecasting feasibility of foehn and the sudden changes in the Dead Sea valley 24 hours in advance using WRF is suggested following the present study. These forecasts can be most valuable for the region affected by pollution penetration from the metropolitan coastal zone.

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High resolution nested model for the Cyprus, NE Levantine Basin, eastern Mediterranean Sea: implementation and climatological runs

Annales Geophysicae ◽

10.5194/angeo-21-221-2003 ◽

2003 ◽

Vol 21 (1) ◽

pp. 221-236 ◽

Cited By ~ 10

Author(s):

G. Zodiatis ◽

R. Lardner ◽

A. Lascaratos ◽

G. Georgiou ◽

G. Korres ◽

...

Keyword(s):

High Resolution ◽

Mediterranean Sea ◽

General Circulation ◽

Eastern Mediterranean ◽

Pilot Project ◽

Ocean Model ◽

Eastern Mediterranean Sea ◽

Coastal Shelf ◽

Forecasting System ◽

The Mediterranean

Abstract. A high resolution nested flow model for the coastal, shelf and open sea areas of the Cyprus Basin, NE Levantine, eastern Mediterranean Sea is implemented to fulfil the objectives of the Mediterranean Forecasting System Pilot Project, funded by the EU. The Cyprus coastal ocean model is nested entirely within a coarse regional grid model of the eastern Mediterranean Sea, using the MODB climatology for initialisation and the ECMWF perpetual year surface forcing. The nested simulations of the Cyprus model were able to reproduce, with greater detail, flow features similar to those of the coarse grid regional model. The project results show the feasibility of the approach for the development of an operational forecasting system in the Mediterranean Sea, particularly in the Cyprus coastal/shelf sea area. Key words. Oceanography: general (descriptive and regional oceanography; numerical modelling) Oceanography: physical (general circulation)

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A high resolution melting method for the molecular identification of the potentially toxic diatom Pseudo-nitzschia spp. in the Mediterranean Sea

Scientific Reports ◽

10.1038/s41598-017-04245-z ◽

2017 ◽

Vol 7 (1) ◽

Cited By ~ 10

Author(s):

Laura Pugliese ◽

Silvia Casabianca ◽

Federico Perini ◽

Francesca Andreoni ◽

Antonella Penna

Keyword(s):

High Resolution ◽

Mediterranean Sea ◽

Molecular Identification ◽

High Resolution Melting ◽

Melting Method ◽

The Mediterranean

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A High Resolution Reanalysis for the Mediterranean Sea

Frontiers in Earth Science ◽

10.3389/feart.2021.702285 ◽

2021 ◽

Vol 9 ◽

Author(s):

Romain Escudier ◽

Emanuela Clementi ◽

Andrea Cipollone ◽

Jenny Pistoia ◽

Massimiliano Drudi ◽

...

Keyword(s):

High Resolution ◽

Mediterranean Sea ◽

Sea Level ◽

Large Scale ◽

Mixed Layer Depth ◽

Horizontal Resolution ◽

Continuous Increase ◽

The Past ◽

The Mediterranean

In order to be able to forecast the weather and estimate future climate changes in the ocean, it is crucial to understand the past and the mechanisms responsible for the ocean variability. This is particularly true in a complex area such as the Mediterranean Sea with diverse dynamics like deep convection and overturning circulation. To this end, effective tools are ocean reanalyses or reconstructions of the past ocean state. Here we present a new physical reanalysis of the Mediterranean Sea at high resolution, developed in the Copernicus Marine Environment Monitoring Service (CMEMS) framework. The hydrodynamic model is based on the Nucleus for European Modelling of the Ocean (NEMO) combined with a variational data assimilation scheme (OceanVar). The model has a horizontal resolution of 1/24° and 141 unevenly distributed vertical z* levels. It provides daily and monthly temperature, salinity, current, sea level and mixed layer depth as well as hourly fields for surface velocities and sea level. ECMWF ERA-5 atmospheric fields force the model and daily boundary conditions in the Atlantic are taken from a global reanalysis. The reanalysis covers the 33 years from 1987 to 2019. Initialized from SeaDataNet climatology in January 1985, it reaches a nominal state after a 2-years spin-up. In-situ data from CTD, ARGO floats and XBT are assimilated into the model in combination with satellite altimetry observations. This reanalysis has been validated and assessed through comparison to in-situ and satellite observations as well as literature climatologies. The results show an overall improvement of the comparison with observations and a better representation of the main dynamics of the region compared to a previous, lower resolution (1/16°), reanalysis. Temperature and salinity RMSD are decreased by respectively 14 and 18%. The salinity biases at depth of the previous version are corrected. Climate signals show continuous increase of the temperature and salinity, confirming estimates from observations and other reanalysis. The new reanalysis will allow the study of physical processes at multi-scales, from the large scale to the transient small mesoscale structures and the selection of climate indicators for the basin.

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High-Resolution Reanalysis of the Mediterranean Sea Biogeochemistry (1999–2019)

Frontiers in Marine Science ◽

10.3389/fmars.2021.741486 ◽

2021 ◽

Vol 8 ◽

Author(s):

Gianpiero Cossarini ◽

Laura Feudale ◽

Anna Teruzzi ◽

Giorgio Bolzon ◽

Gianluca Coidessa ◽

...

Keyword(s):

High Resolution ◽

Mediterranean Sea ◽

Dissolved Inorganic Carbon ◽

Initial Conditions ◽

Marine Ecosystem ◽

World Ocean ◽

Spatial And Temporal Variability ◽

State Variables ◽

Nutrient Inputs ◽

The Mediterranean

Ocean reanalyses integrate models and observations to provide a continuous and consistent reconstruction of the past physical and biogeochemical ocean states and variability. We present a reanalysis of the Mediterranean Sea biogeochemistry at a 1/24° resolution developed within the Copernicus Marine Environment Monitoring Service (CMEMS) framework. The reanalysis is based on the Biogeochemical Flux Model (BFM) coupled with a variational data assimilation scheme (3DVarBio) and forced by the Nucleus for European Modeling of the Ocean (NEMO)–OceanVar physical reanalysis and European Centre for medium-range weather forecasts (ECMWF) reanalysis ERA5 atmospheric fields. Covering the 1999–2019 period with daily means of 12 published and validated biogeochemical state variables, the reanalysis assimilates surface chlorophyll data and integrates EMODnet data as initial conditions, in addition to considering World Ocean Atlas data at the Atlantic boundary, CO2 atmospheric observations, and yearly estimates of riverine nutrient inputs. With the use of multiple observation sources (remote, in situ, and BGC-Argo), the quality of the biogeochemical reanalysis is qualitatively and quantitatively assessed at three validation levels including the evaluation of 12 state variables and fluxes and several process-oriented metrics. The results indicate an overall good reanalysis skill in simulating basin-wide values and variability in the biogeochemical variables. The uncertainty in reproducing observations at the mesoscale and weekly temporal scale is satisfactory for chlorophyll, nutrient, oxygen, and carbonate system variables in the epipelagic layers, whereas the uncertainty increases for a few variables (i.e., oxygen and ammonium) in the mesopelagic layers. The vertical dynamics of phytoplankton and nitrate are positively evaluated with specific metrics using BGC-Argo data. As a consequence of the continuous increases in temperature and salinity documented in the Mediterranean Sea over the last 20 years and atmospheric CO2 invasion, we observe basin-wide biogeochemical signals indicating surface deoxygenation, increases in alkalinity, and dissolved inorganic carbon concentrations, and decreases in pH at the surface. The new, high-resolution reanalysis, open and freely available from the Copernicus Marine Service, allows users from different communities to investigate the spatial and temporal variability in 12 biogeochemical variables and fluxes at different scales (from the mesoscale to the basin-wide scale and from daily to multiyear scales) and the interaction between physical and biogeochemical processes shaping Mediterranean marine ecosystem functioning.

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Monitoring and forecasting of marine pollution in the Mediterranean Sea: the ODYSSEA project approach

10.5194/egusphere-egu2020-15191 ◽

2020 ◽

Author(s):

Katerina Spanoudaki ◽

Nikolaos Kokkos ◽

Konstantinos Zachopoulos ◽

Georgios Sylaios ◽

Nikolaos Kampanis ◽

...

Keyword(s):

Water Quality ◽

High Resolution ◽

Mediterranean Sea ◽

Oil Spill ◽

Mediterranean Basin ◽

Shelf Zone ◽

Forecasting System ◽

Marine Data ◽

The Mediterranean ◽

The Mediterranean Basin

The H2020 funded project ODYSSEA (http://odysseaplatform.eu/) aims to make Mediterranean marine data easily accessible and operational to a broad range of users of the marine space. ODYSSEA develops an interoperable and cost-effective platform, fully integrating networks of observing and forecasting systems across the Mediterranean basin, addressing both the open sea and the coastal zone. The platform integrates marine data from existing Earth Observing Systems, such as Copernicus and EMODnet, receives and processes novel, newly produced datasets (through high-resolution models and on-line sensors such as a novel microplastics sensor) from nine prototype Observatories established across the Mediterranean basin, and applies advanced algorithms to organise, homogenise and fuse the large quantities of data in order to provide to various end-user groups and stakeholders both primary data and on-demand derived data services.The nine ODYSSEA Observatories are established across the whole Mediterranean basin, covering also areas of marine data gaps along the North African and Middle East coastline. The Observatories comprise observing and forecasting systems and cover coastal and shelf zone environments, Marine Protected Areas and areas with increased human pressure. The operational forecasting system of the Observatories consists of a &#8216;chain&#8217; of dynamically coupled, high-resolution numerical models comprised of a) the hydrodynamic model Delft3D-FLOW, b) the wave model Delft3D-WAVE (SWAN), c) the water quality model DELWAQ, d) the oil spill fate and transport model MEDSLIK-II, e) the ecosystem model ECOPATH, and f) the in-house mussel farm model developed by the Democritus University of Thrace. This operational system provides forecasts, early warnings and alerts for currents, waves, water quality parameters, oil spill pollution and ecosystem status. In this work, the ODYSSEA forecasting system (developed with the Delft-FEWS software) is implemented for simulating oil spill pollution for the Thracian Sea Observatory. &#160;The area is biodiversity rich and an important spawning and nursery ground for small pelagic species, while in Kavala Gulf, oil exploitation takes place. The Lagrangian oil spill model MEDSLIK-II has been coupled to high-resolution oceanographic fields (currents, temperature, Stokes drift velocity), produced by Delft3D-FLOW and SWAN, and NOAA GFS atmospheric forcing. The hydrodynamic and wave models have been configured for the Thracian Sea based on dynamic downscaling of CMEMS products to a grid resolution of 1/120&#176;. Seasonal hazard maps (surface oil slick, beached oil) are produced employing multiple oil spill scenarios using multi-year hydrodynamics. The results highlight the hazard faced by Thracian Sea Observatory coasts.&#160;Acknowledgements: This research has received funding from the European Union&#8217;s Horizon 2020 research and innovation programme ODYSSEA: OPERATING A NETWORK OF INTEGRATED OBSERVATORY SYSTEMS IN THE MEDITERRANEAN SEA, GA No 72727.

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Levant Basin as a key for Understanding the Messinian Salinity Crisis: Challenging the Desiccation Paradigm

10.5194/egusphere-egu2020-4040 ◽

2020 ◽

Author(s):

Zohar Gvirtzman ◽

Vinicio Manzi ◽

Ran Calvo ◽

Ittai Gavrieli ◽

Rocco Gennari ◽

...

Keyword(s):

High Resolution ◽

Mediterranean Sea ◽

Water Column ◽

Mediterranean Basin ◽

Eastern Mediterranean ◽

Messinian Salinity Crisis ◽

Seismic Surveys ◽

Salt Rocks ◽

The Mediterranean ◽

Levant Basin

The Messinian salinity crisis (MSC) is an extreme event in Earth history during which a salt giant (>1&#215;106 km3) accumulated on the Mediterranean seafloor within ~640 kyrs. The Messinian salt giant was formed about 6 million years ago when the restriction of water exchanges between the Atlantic Ocean and the Mediterranean Sea turned the Mediterranean into an enormous saline basin. After more than 40 years of research, the timing and the depositional environments of shallow (<200 m) and intermediate (200-1000 m) water-depth Messinian basins are known quite well from onshore outcrops. But what happened in the deepest portions of the Mediterranean Sea is still unclear, because the information about offshore successions is mainly based on geophysical data with no rock samples that can be dated. The Levant Basin is the only deep Mediterranean basin where the entire Messinian section has been penetrated by wells tied to high resolution 3D seismic surveys. Here we present two studies challenging the desiccation paradigm dominating the MSC scientific literature for more than 40 years. The first study focuses on the nearly flat top erosion surface (TES) that truncates a basinward-tilted Messinian evaporitic succession. This truncation is commonly interpreted to be the result of subaerial erosion at the end of the MSC. However, based on high resolution seismic surveys and wireline logs, we show that (1) the TES is actually an intra-Messinian truncation surface (IMTS) located ~100 m below the Messinian-Zanclean boundary; (2) the topmost, post-truncation, Messinian unit is very different from the underlying salt deposits and consists mostly of shale, sand, and anhydrite showing typical 87Sr/86Sr values and fauna assemblages from stage 3; and (3) the flat IMTS is a dissolution surface related to significant dilution and stratification of the water column during the transition from stage 2 to stage 3. We suggest that dissolution occurred upslope where salt rocks at the seabed were exposed to the upper diluted brine, while downslope the salt rocks were preserved because submerged in the deeper halite-saturated layer. The model, which requires a stratified water column, is inconsistent with a complete desiccation of the eastern Mediterranean Sea. The second study focuses on the onset of the Messinian salinity crisis in the deep Eastern Mediterranean basin. Biostratigraphy and astronomical tuning of the Messinian pre-salt succession in the Levant Basin allows for the first time the reconstruction of a detailed chronology of the MSC events in deep setting and their correlation with marginal records that supports the CIESM (2008) 3-stage model. Our main conclusions are (1) MSC events were synchronous across marginal and deep basins, (2) MSC onset in deep basins occurred at 5.97 Ma, (3) only foraminifera-barren, evaporite-free shales accumulated in deep settings between 5.97 and 5.60 Ma, (4) deep evaporites (sulfate and halite) deposition started later, at 5.60 Ma. The wide synchrony of events implies inter-sub-basin connection during the whole salinity crisis and is not compatible with large sea-level fall that would have separated the eastern and western basins producing diachronic processes.

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