scholarly journals An Integrated Reconstruction of the Multiannual Wave Pattern in the Gulf of Naples (South-Eastern Tyrrhenian Sea, Western Mediterranean Sea)

2020 ◽  
Vol 8 (5) ◽  
pp. 372
Author(s):  
Simona Saviano ◽  
Daniela Cianelli ◽  
Enrico Zambianchi ◽  
Fabio Conversano ◽  
Marco Uttieri
Keyword(s):  
Wave Field ◽  
Large Scale ◽  
Acoustic Doppler Current Profiler ◽  
Wave Pattern ◽  
Western Mediterranean ◽  
Ocean Dynamics ◽  
Tyrrhenian Sea ◽  
Gulf Of Naples ◽  
South Eastern ◽  
The Impact

Surface gravity waves retrieved by a network of HF (High Frequency) radars and measured in situ by an ADCP (Acoustic Doppler Current Profiler) current meter connected to an elastic beacon were used to carry out a multiple-year characterization of the wave field of the Gulf of Naples (south-eastern Tyrrhenian Sea, western Mediterranean). The aim of the work was to create a climatology of the study area and to demonstrate the potential of an integrated platform for coastal studies. The patterns recorded by the different instruments were in agreement with the wave climatology of the southern Tyrrhenian Sea as well as with previous scores for the same area. The results presented in this work also highlight seasonal and interannual consistency in the wave patterns for each site. In a wider context, this study demonstrates the potential of HF radars as long-term monitoring tools of the wave field in coastal basins, and supports the development of integrated observatories to address large-scale scientific challenges such as coastal ocean dynamics and the impact of global change on the local dynamics.

Structures megametriques et evolution de la mer Tyrrhenienne et des zones perityrrheniennes

1962 ◽  
Vol S7-IV (5) ◽  
pp. 760-773 ◽  
Author(s):  
Claude Grandjacquet
Keyword(s):  
Large Scale ◽  
Middle Miocene ◽  
Southern Italy ◽  
Western Mediterranean ◽  
Tyrrhenian Sea ◽  
African Continent ◽  
Lower Eocene ◽  
Structural History ◽  
History Of

Abstract A large view of the evolution and structural history of the Tyrrhenian sea and bordering areas suggests that towards the end of the Permian distensions occurring in the western Mediterranean resulted in the opening of a passage to the Atlantic. Lower Eocene deformations along the Sicilian-Tunisian front were either due to local marginal disequilibrium or to the northern drift of the African continent. Oligocene emergence is evident in the Apennines and in Calabria through the existence of widespread hiatuses and by bauxitic and ferruginous beds. Large scale Oligocene movements brought the African continent to its maximum proximity with Europe. It was in the same period that the clay scaglia and flysch nappes began sliding in Tuscany although the movement of Calabrian nappes in southern Italy did not occur until the lower and middle Miocene.

scholarly journals Surface transport of DOC acts as a trophic link among Mediterranean sub-basins

2018 ◽  
Author(s):  
Chiara Santinelli ◽  
Roberto Iacono ◽  
Ernesto Napolitano ◽  
Maurizio Ribera d'Alcalá
Keyword(s):  
Integrated Approach ◽  
Atlantic Water ◽  
Western Mediterranean ◽  
Global Ocean ◽  
Tyrrhenian Sea ◽  
Surface Transport ◽  
Trophic Link ◽  
Western Mediterranean Sea ◽  
Surface Circulation ◽  
The Impact

Abstract. Characterizing carbon cycling and redistribution in the ocean is an important issue for Mankind, because it may affect key ecosystem services, e.g., support to climate system and food provision. In this paper, using an integrated approach, we explore the impact of the surface circulation on carbon dynamics in the Western Mediterranean Sea, where strong inter-basin differences in primary production do exist. Detailed information on the surface circulation, derived from high-resolution model simulations, is combined with the analysis of accurate, repeated dissolved organic carbon (DOC) data. Our work indicates that the advection of the Atlantic Water acts as a trophic link between the Algerian Basin and the Tyrrhenian Sea, determining a flux of 8.8–37.9 × 1012 g DOC yr−1 into the basin. Thus, surface transport of DOC can redistribute chemical energy among regions with different trophic regimes. We hypothesize that this overlooked mechanism plays an important role also in the global ocean.

scholarly journals How Momentum Coupling Affects SST Variance and Large-Scale Pacific Climate Variability in CESM

2018 ◽  
Vol 31 (7) ◽  
pp. 2927-2944 ◽  
Author(s):  
Sarah M. Larson ◽  
Daniel J. Vimont ◽  
Amy C. Clement ◽  
Ben P. Kirtman
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Ocean Dynamics ◽  
Easterly Wind ◽  
Tropical Forcing ◽  
Freshwater Fluxes ◽  
The Pacific ◽  
Anomalous Wind ◽  
Momentum Coupling ◽  
The Impact

The contribution of buoyancy (thermal + freshwater fluxes) versus momentum (wind driven) coupling to SST variance in climate models is a longstanding question. Addressing this question has proven difficult because a gap in the model hierarchy exists between the fully coupled (momentum + buoyancy + ocean dynamics) and slab–mixed layer ocean coupled (thermal with no ocean dynamics) versions. The missing piece is a thermally coupled configuration that permits anomalous ocean heat transport convergence decoupled from the anomalous wind stress. A mechanically decoupled model configuration is provided to fill this gap and diagnose the impact of momentum coupling on SST variance in NCAR CESM. A major finding is that subtropical SST variance increases when momentum coupling is disengaged. An “opposing flux hypothesis” may explain why the subtropics (midlatitudes) experience increased (reduced) variance without momentum coupling. In a subtropical easterly wind regime, Ekman fluxes [Formula: see text] oppose thermal fluxes [Formula: see text], such that when the air and sea are mechanically decoupled [Formula: see text], [Formula: see text] variance increases. As a result, SST variance increases. In a midlatitude westerly regime where [Formula: see text] and [Formula: see text] typically reinforce each other, SST variance is reduced. Changes in mean surface winds with climate change could impact the [Formula: see text] and [Formula: see text] covariance relationships. A by-product of mechanically decoupling the model is the absence of ENSO variability. The Pacific decadal oscillation operates without momentum coupling or tropical forcing, although the pattern is modified with enhanced (reduced) variability in the subtropics (midlatitudes). Results show that Ekman fluxes are an important component to tropical, subtropical, and midlatitude SST variance.

scholarly journals Mapping altimetry in the forthcoming SWOT era by back-and-forth nudging a one-layer quasi-geostrophic model

2020 ◽  
Author(s):  
Florian Le Guillou ◽  
Sammy Metref ◽  
Emmanuel Cosme ◽  
Julien Le Sommer ◽  
Clément Ubelmann ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Large Scale ◽  
Model Simulation ◽  
Interpolation Method ◽  
Ocean Dynamics ◽  
Optimal Interpolation ◽  
Small Scale ◽  
Altimetric Data ◽  
The Impact ◽  
Mean Square Errors

AbstractDuring the past 25 years, altimetric observations of the ocean surface from space have been mapped to provide two dimensional sea surface height (SSH) fields which are crucial for scientific research and operational applications. The SSH fields can be reconstructed from conventional altimetric data using temporal and spatial interpolation. For instance, the standardDUACS products are created with an optimal interpolation method which is effective for both low temporal and low spatial resolution. However, the upcoming next-generation SWOT mission will provide very high spatial resolution but with low temporal resolution.The present paper makes the case that this temporal-spatial discrepancy induces the need for new advanced mapping techniques involving information on the ocean dynamics. An algorithm is introduced, dubbed the BFN-QG, that uses a simple data assimilation method, the back-and-forth nudging, to interpolate altimetric data while respecting quasigeostrophic dynamics. The BFN-QG is tested in an observing system simulation experiments and compared to the DUACS products. The experiments consider as reference the high-resolution numerical model simulation NATL60 from which are produced realistic data: four conventional altimetric nadirs and SWOT data. In a combined nadirs and SWOT scenario, the BFN-QG substantially improves the mapping by reducing the root-mean-square errors and increasing the spectral effective resolution by 40km. Also, the BFN-QG method can be adapted to combine large-scale corrections from nadirs data and small-scale corrections from SWOT data so as to reduce the impact of SWOT correlated noises and still provide accurate SSH maps.

scholarly journals Assessing the impact of SSTs on a simulated medicane using ensemble simulations

2018 ◽  
Author(s):  
Robin Noyelle ◽  
Uwe Ulbrich ◽  
Nico Becker ◽  
Edmund P. Meredith
Keyword(s):  
Climate Model ◽  
Regional Climate ◽  
Western Mediterranean ◽  
Tyrrhenian Sea ◽  
Western Mediterranean Basin ◽  
Minor Influence ◽  
Climate Model Simulations ◽  
Upper Level ◽  
A Minor ◽  
The Impact

Abstract. The sensitivity of the October 1996 medicane in the western Mediterranean basin to sea surface temperatures (SSTs) is investigated via 24-member ensembles of regional climate model simulations. Eleven ensembles are created by uniformly changing SSTs in a range of −4 K to +6 K from the observed field, with a 1 K step. By using a modified phase space diagram and a simple compositing method, it is shown that the SST state has a minor influence on the tracks of the cyclones, but a strong influence on their intensities. Increased SSTs lead to greater probabilities of tropical transitions, to stronger low- and upper-level warm cores, and to lower pressure minima. The tropical transition occurs sooner and lasts longer, which enables a greater number of transitioning cyclones to survive landfall over Sardinia and to re-intensify in the Tyrrhenian Sea. The results demonstrate that SSTs influence the intensity of fluxes from the sea, which leads to greater convective activity before the storms reach their maturity. These results suggest that the processes at steady-state for medicanes are very similar to tropical cyclones.

scholarly journals Profiling float observation of thermohaline staircases in the western Mediterranean Sea and impact on nutrient fluxes

2020 ◽  
Vol 17 (13) ◽  
pp. 3343-3366
Author(s):  
Vincent Taillandier ◽  
Louis Prieur ◽  
Fabrizio D'Ortenzio ◽  
Maurizio Ribera d'Alcalà ◽  
Elvira Pulido-Villena
Keyword(s):  
Mediterranean Sea ◽  
Nutrient Enrichment ◽  
Large Scale ◽  
Western Mediterranean ◽  
Salt Flux ◽  
Tyrrhenian Sea ◽  
Profiling Float ◽  
Western Mediterranean Sea ◽  
Deep Waters ◽  
Density Ratios

Abstract. In the western Mediterranean Sea, Levantine intermediate waters (LIW), which circulate below the surface productive zone, progressively accumulate nutrients along their pathway from the Tyrrhenian Sea to the Algerian Basin. This study addresses the role played by diffusion in the nutrient enrichment of the LIW, a process particularly relevant inside step-layer structures extending down to deep waters – structures known as thermohaline staircases. Profiling float observations confirmed that staircases develop over epicentral regions confined in large-scale circulation features and maintained by saltier LIW inflows on the periphery. Thanks to a high profiling frequency over the 4-year period 2013–2017, float observations reveal the temporal continuity of the layering patterns encountered during the cruise PEACETIME and document the evolution of layer properties by about +0.06 ∘C in temperature and +0.02 in salinity. In the Algerian Basin, the analysis of in situ lateral density ratios untangled double-diffusive convection as a driver of thermohaline changes inside epicentral regions and isopycnal diffusion as a driver of heat and salt exchanges with the surrounding sources. In the Tyrrhenian Sea, the nitrate flux across thermohaline staircases, as opposed to the downward salt flux, contributes up to 25 % of the total nitrate pool supplied to the LIW by vertical transfer. Overall, however, the nutrient enrichment of the LIW is driven mostly by other sources, coastal or atmospheric, as well as by inputs advected from the Algerian Basin.

scholarly journals Assessing the impact of sea surface temperatures on a simulated medicane using ensemble simulations

2019 ◽  
Vol 19 (4) ◽  
pp. 941-955 ◽  
Author(s):  
Robin Noyelle ◽  
Uwe Ulbrich ◽  
Nico Becker ◽  
Edmund P. Meredith
Keyword(s):  
Climate Model ◽  
Regional Climate ◽  
Western Mediterranean ◽  
Sea Surface ◽  
Tyrrhenian Sea ◽  
Sea Surface Temperatures ◽  
Surface Temperatures ◽  
Western Mediterranean Basin ◽  
A Minor ◽  
The Impact

Abstract. The sensitivity of the October 1996 Medicane in the western Mediterranean basin to sea surface temperatures (SSTs) is investigated with a regional climate model via ensemble sensitivity simulations. For 11 SST states, ranging from −4 K below to +6 K above the observed SST field (in 1 K steps), 24-member ensembles of the medicane are simulated. By using a modified phase space diagram and a simple compositing method, it is shown that the SST state has a minor influence on the tracks of the cyclones but a strong influence on their intensities. Increased SSTs lead to greater probabilities of tropical transitions, to stronger lower- and upper-level warm cores and to lower pressure minima. The tropical transition occurs sooner and lasts longer, which enables a greater number of transitioning cyclones to survive landfall over Sardinia and re-intensify in the Tyrrhenian Sea. The results demonstrate that SSTs influence the intensity of fluxes from the sea, which leads to greater convective activity before the storms reach their maturity. These results suggest that the processes at steady state for medicanes are very similar to tropical cyclones.

scholarly journals The impact of initial spread calibration on the RELO ensemble and its application to Lagrangian dynamics

2013 ◽  
Vol 20 (5) ◽  
pp. 621-641 ◽  
Author(s):  
M. Wei ◽  
G. Jacobs ◽  
C. Rowley ◽  
C. N. Barron ◽  
P. Hogan ◽  
...  
Keyword(s):  
Large Scale ◽  
Spatial Scales ◽  
Ocean Model ◽  
Ocean Dynamics ◽  
Brier Score ◽  
Small Scale ◽  
Naval Research ◽  
Model Forecast ◽  
Single Model ◽  
The Impact

Abstract. A number of real-time ocean model forecasts were carried out successfully at Naval Research Laboratory (NRL) to provide modeling support and numerical guidance to the CARTHE GLAD at-sea experiment during summer 2012. Two RELO ensembles and three single models using NCOM and HYCOM with different resolutions were carried out. A calibrated ensemble system with enhanced spread and reliability was developed to better support this experiment. The calibrated ensemble is found to outperform the un-calibrated ensemble in forecasting accuracy, skill, and reliability for all the variables and observation spaces evaluated. The metrics used in this paper include RMS error, anomaly correlation, PECA, Brier score, spread reliability, and Talagrand rank histogram. It is also found that even the un-calibrated ensemble outperforms the single forecast from the model with the same resolution. The advantages of the ensembles are further extended to the Lagrangian framework. In contrast to a single model forecast, the RELO ensemble provides not only the most likely Lagrangian trajectory for a particle in the ocean, but also an uncertainty estimate that directly reflects the complicated ocean dynamics, which is valuable for decision makers. The examples show that the calibrated ensemble with more reliability can capture trajectories in different, even opposite, directions, which would be missed by the un-calibrated ensemble. The ensembles are applied to compute the repelling and attracting Lagrangian coherent structures (LCSs), and the uncertainties of the LCSs, which are hard to obtain from a single model forecast, are estimated. It is found that the spatial scales of the LCSs depend on the model resolution. The model with the highest resolution produces the finest, small-scale, LCS structures, while the model with lowest resolution generates only large-scale LCSs. The repelling and attracting LCSs are found to intersect at many locations and create complex mesoscale eddies. The fluid particles and drifters in the middle of these tangles are subject to attraction and repulsion simultaneously from these two kinds of LCSs. As a result, the movements of particles near the Deepwater Horizon (DWH) location are severely limited. This is also confirmed by the Lagrangian trajectories predicted by the ensembles.

Records of Oncaeidae (Copepoda) from the Gulf of Naples, with new records of three species of Triconia

2008 ◽  
Vol 88 (7) ◽  
pp. 1407-1415 ◽  
Author(s):  
Iole Di Capua ◽  
Geoff A. Boxshall
Keyword(s):  
New Records ◽  
Small Body ◽  
Western Mediterranean ◽  
Tyrrhenian Sea ◽  
Scanning Electron Micrographs ◽  
Gulf Of Naples ◽  
Western Mediterranean Sea ◽  
Surface Ornamentation ◽  
First Time ◽  
New Discovery

Three species of Oncaeidae, Triconia umerus, T. hawii and T. rufa are reported for the first time in the coastal waters of the Gulf of Naples, Tyrrhenian Sea, western Mediterranean Sea. They were found in meso-zooplankton samples collected in 2004 and were absent from samples collected prior to 2004. Specimens of Triconia umerus and T. hawii were compared with material collected from the type locality (the Red Sea). In order to facilitate identification, brief differential diagnoses, supported by scanning electron micrographs, are presented for the five species of Triconia that have small body size (450 to 600 μm) and co-occur in the upper 50 m of the water column of the Gulf of Naples. Surface ornamentation on the genital double-somite of the female is reported in T. minuta and T. hawii for the first time, but it is difficult to observe using light microscopy and we infer that it has probably been overlooked in these species hitherto. Possible explanations for the new discovery of these species in such a well-studied area are discussed and it is suggested that they represent relatively recent additions to the fauna. A key to the eleven species of Oncaeidae found in the Gulf of Naples is presented.

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