Time-clustering of wave storms in the Mediterranean Sea

Abstract. In this contribution we identify storm time-clustering in the Mediterranean Sea through the analysis of the spatial distribution of the Allan Factor. This parameter is evaluated from long time series of wave height provided by means of oceanographic buoy measurements and hindcast re-analysis spanning in the period 1979–2014 and characterized by a horizontal resolution of about 0.1 degree in longitude and latitude and a temporal sampling of one hour (Mentaschi et a., 2015). Results reveal clustering mainly for two distinct ranges of time scales. The first range of time scales (12 hrs to 50 days) is associated to sequences of storms generated by the persistence of the same meteorological system. The second range, associated to timescales beteween 50 and 100 days, reveals seasonal fluctuations. Transitional regimes are present at some locations in the basin. The spatial distribution of the Allan Factor reveals that the clustering at smaller time scales is present in the North-West of the Mediterranean, while clustering at larger scales is observed in the whole basin. This analysis is believed to be important to assess the local increased flood and coastal erosion risks due to storm clustering.

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Time clustering of wave storms in the Mediterranean Sea

Natural Hazards and Earth System Science ◽

10.5194/nhess-17-505-2017 ◽

2017 ◽

Vol 17 (3) ◽

pp. 505-514 ◽

Cited By ~ 4

Author(s):

Giovanni Besio ◽

Riccardo Briganti ◽

Alessandro Romano ◽

Lorenzo Mentaschi ◽

Paolo De Girolamo

Keyword(s):

Spatial Distribution ◽

Mediterranean Sea ◽

Horizontal Resolution ◽

Comprehensive Analysis ◽

North West ◽

Temporal Sampling ◽

The North ◽

Allan Factor ◽

Long Time ◽

The Mediterranean

Abstract. In this contribution we identify storm time clustering in the Mediterranean Sea through a comprehensive analysis of the Allan factor. This parameter is evaluated from a long time series of wave height provided by oceanographic buoy measurements and hindcast reanalysis of the whole basin, spanning the period 1979–2014 and characterized by a horizontal resolution of about 0.1° in longitude and latitude and a temporal sampling of 1 h Mentaschi et al. (2015). The nature of the processes highlighted by the AF and the spatial distribution of the parameter are both investigated. Results reveal that the Allan factor follows different curves at two distinct timescales. The range of timescales between 12 h to 50 days is characterized by a departure from the Poisson distribution. For timescales above 50 days, a cyclic Poisson process is identified. The spatial distribution of the Allan factor reveals that the clustering at smaller timescales is present to the north-west of the Mediterranean, while seasonality is observed across the whole basin. This analysis is believed to be important for assessing the local increased flood and coastal erosion risks due to storm clustering.

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From 1/4° to 1/8°: Influence of Spatial Resolution on Eddy Detection Using Altimeter Data

Remote Sensing ◽

10.3390/rs14010149 ◽

2021 ◽

Vol 14 (1) ◽

pp. 149

Author(s):

Yinuo Wang ◽

Xiaoyan Chen ◽

Guiyan Han ◽

Pingping Jin ◽

Jie Yang

Keyword(s):

Mediterranean Sea ◽

Spatial Resolution ◽

Propagation Distance ◽

Altimeter Data ◽

The South ◽

North West ◽

Temporal Sampling ◽

The North ◽

The Mediterranean ◽

Eddy Detection

A substantial portion of ocean eddies, especially small ones, may be missed due to insufficient spatial or temporal sampling by satellite altimetry. In order to illustrate the influence of spatial resolution on eddy detection, this study provides a comparison of eddy identification, tracking, and analysis between two sets of merged altimeter data with spatial resolutions of 1/4° and 1/8°. One main study area (the Mediterranean Sea), and three confirmatory areas (the South-China Sea, the North-West Pacific, and the South-East Pacific) are chosen. The results show that the number and density of eddies captured by the 1/8° data are about twice as much as those captured by the 1/4° data, while the ratios of corresponding eddy parameters, i.e., radius, amplitude, (eddy kinetic energy (EKE)) are about 0.6–0.8 (1.3) for the two datasets (1/8° ÷ 1/4°). Long-term eddy tracking (1993–2018) is conducted in the Mediterranean Sea, indicating that the improvement in spatial resolution will increase the observed values of both the lifetime and the propagation distance of robust eddies. The number of eddies identified using the 1/4° data only accounts for ~30% to 60% of those identified using the 1/8° data. However, for eddies that can be detected using the two datasets, ~5% to 10% present errors (i.e., confusion). In comparison between the four regions, we find that for the enclosed seas with complex conditions, the increase in spatial resolution may lead to more significant improvements in the efficiency and accuracy of eddy detection.

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Bioluminescence and fluorescence of three sea pens in the north-west Mediterranean sea

10.1101/2020.12.08.416396 ◽

2020 ◽

Author(s):

Warren R Francis ◽

Anaïs Sire de Vilar

Keyword(s):

Mediterranean Sea ◽

Dark Adaptation ◽

Fluorescence Spectra ◽

Green Light ◽

Emission Spectra ◽

North West ◽

The North ◽

Light Production ◽

Long Time ◽

Basic Parameters

AbstractBioluminescence of Mediterranean sea pens has been known for a long time, but basic parameters such as the emission spectra are unknown. Here we examined bioluminescence in three species of Pennatulacea, Pennatula rubra, Pteroeides griseum, and Veretillum cynomorium. Following dark adaptation, all three species could easily be stimulated to produce green light. All species were also fluorescent, with bioluminescence being produced at the same sites as the fluorescence. The shape of the fluorescence spectra indicates the presence of a GFP closely associated with light production, as seen in Renilla. Our videos show that light proceeds as waves along the colony from the point of stimulation for all three species, as observed in many other octocorals. Features of their bioluminescence are strongly suggestive of a “burglar alarm” function.

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New Data on the Biology and Fisheries of the Threatened Palinurus elephas (Fabricius, 1787) (Decapoda, Achelata, Palinuridae) from the North-West Aegean Sea, Greece

Water ◽

10.3390/w12092390 ◽

2020 ◽

Vol 12 (9) ◽

pp. 2390

Author(s):

Thodoros E. Kampouris ◽

Drosos Koutsoubas ◽

Debora Milenkova ◽

Georgios Economidis ◽

Stylianos Tamvakidis ◽

...

Keyword(s):

Mediterranean Sea ◽

Eastern Mediterranean ◽

Spiny Lobster ◽

Aegean Sea ◽

North West ◽

The North ◽

Coastal Species ◽

The Mediterranean ◽

Species Specific ◽

Palinurus Elephas

The European spiny lobster Palinurus elephas is a vulnerable species that inhabits and is harvested in the Mediterranean Sea and the adjacent Atlantic waters. The fisheries associated with the spiny lobster are mainly conducted with tangle nets, trammel nets, pots, and creels. The fishing pressure has greatly reduced their numbers, changing them from a common shallow coastal species to a largely remnant population. The relative research on the species’ biology and fisheries from the eastern Mediterranean Sea is almost absent. The fishery along the Chalkidiki Peninsula, Greece, is multispecies, and fishing is conducted by a small number of artisanal fishermen mainly using trammel nets. The lobster stock—both spiny and clawed lobsters—declined significantly during the late 1980s and early 1990s, later than most cases in the Mediterranean Sea. However, data regarding the nature and status of the fishery associated with the spiny lobster in Greece are lacking. Data regarding the characteristics of the spiny regional fishery were obtained by interviews and questionnaires. Additionally, fishery surveys were conducted during the main lobster fishing season from 1 May 2017 to 31 August 2017. Sixteen species were identified (15 finfish species and one invertebrate species) as targeted. In total, 79 spiny lobsters were sampled in this study; the population’s sex ratio significantly diverts from the theoretical 1:1 (χ2 = 4.57; p < 0.05), and males were dominant. Both male and female individuals demonstrate negative allometric growth profiles. In addition, no significant differences were observed between sexes. In Greece, thus far, the knowledge and information are sporadic, limited, and/or species-specific, most of which regard finfish fisheries. Furthermore, the national legislation is rather complicated—or too generalized—thus creating great uncertainties. The in-depth knowledge and experience of fishermen should be further acknowledged and utilized, and wider collaborations among scientists, practitioners, and policy-makers should be established. The present study poses some thoughts on the effectiveness of the recent EU Landing Obligation and its contribution to the potential restoration of the species.

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First record of Dipolydora blakei (Annelida: Spionidae) from Europe: Greece, Mediterranean Sea

Mediterranean Marine Science ◽

10.12681/mms.322 ◽

2013 ◽

Vol 14 (1) ◽

pp. 19 ◽

Cited By ~ 1

Author(s):

V. I. RADASHEVSKY ◽

N. SIMBOURA

Keyword(s):

New England ◽

Mediterranean Sea ◽

Coastal Waters ◽

Aegean Sea ◽

First Record ◽

Ionian Sea ◽

North West ◽

The North ◽

The Mediterranean ◽

Of Greece

The spionid polychaete Dipolydora blakei is identified from benthic samples collected in the Aegean Sea off Chalkis and the Ionian Sea off Kalamitsi, both on the coast of Greece. Adults of D. blakei are characterized by having the falcate spines of chaetiger 5 with a large lateral tooth and bristles on the convex side of a long and pointed main fang, awl-like spines in posterior notopodia, branchiae beginning from chaetiger 7 and a pygidium with two lateral lobes. This is the first report of the species from the Mediterranean Sea and European waters and the second record (after one from Brazil) outside its type locality in deep-water off New England in the north-west Atlantic Ocean. The morphology of the Greek specimens is described and illustrated and diagnostic characters of the species are discussed. The origin of these specimens in the coastal waters of Greece is uncertain and the species is considered as cryptogenic in the Mediterranean Sea. An identification key to Dipolydora species with bristle-topped falcate spines in chaetiger 5 known from the Mediterranean Sea and European waters is provided.

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Relationship Between Aromatic Hydrocarbons and Pelagic Tar in the Mediterranean Sea, 1974–75

Environmental Conservation ◽

10.1017/s0376892900006354 ◽

1978 ◽

Vol 5 (4) ◽

pp. 295-297 ◽

Cited By ~ 3

Author(s):

Adam Zsolnay ◽

Byron F. Morris ◽

James N. Butler

Keyword(s):

Aromatic Hydrocarbon ◽

Mediterranean Sea ◽

Aromatic Hydrocarbons ◽

Sargasso Sea ◽

The Baltic Sea ◽

Detailed Report ◽

North West ◽

The North ◽

The Mediterranean ◽

The Baltic

During the winter of 1974–75, both tar and aromatic hydrocarbons were sampled in the Mediterranean Sea. A detailed report of the tar findings were given in a previous paper (Morris et al., 1975). Aromatic hydrocarbon concentrations at a depth of 1 m averaged 167 ng/1 (expressed as phenanthrene equivalents). This is only about 60% as great as the average aromatic hydrocarbon concentration found in the Baltic Sea, but is 5 times greater than what was found in the north-west Atlantic—including the Sargasso Sea (Zsolnay, 1977).No relationship was found between tar and aromatic hydrocarbon concentrations. This would indicate that the concentration of the latter is dependent upon other factors—such as the presence of other organic compounds that are capable of keeping the hydrophobic hydrocarbons in the water column by ‘solubilization.’

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Impact of air–sea coupling on the climate change signal over the Iberian Peninsula

Climate Dynamics ◽

10.1007/s00382-021-05812-x ◽

2021 ◽

Author(s):

Alba de la Vara ◽

William Cabos ◽

Dmitry V. Sein ◽

Claas Teichmann ◽

Daniela Jacob

Keyword(s):

Climate Change ◽

Iberian Peninsula ◽

Mediterranean Sea ◽

Large Scale ◽

Regional Distribution ◽

Coupled Model ◽

Climate Change Signal ◽

The North ◽

The Mediterranean ◽

The Impact

AbstractIn this work we use a regional atmosphere–ocean coupled model (RAOCM) and its stand-alone atmospheric component to gain insight into the impact of atmosphere–ocean coupling on the climate change signal over the Iberian Peninsula (IP). The IP climate is influenced by both the Atlantic Ocean and the Mediterranean sea. Complex interactions with the orography take place there and high-resolution models are required to realistically reproduce its current and future climate. We find that under the RCP8.5 scenario, the generalized 2-m air temperature (T2M) increase by the end of the twenty-first century (2070–2099) in the atmospheric-only simulation is tempered by the coupling. The impact of coupling is specially seen in summer, when the warming is stronger. Precipitation shows regionally-dependent changes in winter, whilst a drier climate is found in summer. The coupling generally reduces the magnitude of the changes. Differences in T2M and precipitation between the coupled and uncoupled simulations are caused by changes in the Atlantic large-scale circulation and in the Mediterranean Sea. Additionally, the differences in projected changes of T2M and precipitation with the RAOCM under the RCP8.5 and RCP4.5 scenarios are tackled. Results show that in winter and summer T2M increases less and precipitation changes are of a smaller magnitude with the RCP4.5. Whilst in summer changes present a similar regional distribution in both runs, in winter there are some differences in the NW of the IP due to differences in the North Atlantic circulation. The differences in the climate change signal from the RAOCM and the driving Global Coupled Model show that regionalization has an effect in terms of higher resolution over the land and ocean.

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The spatio-temporal distribution of lightning over Israel and the neighboring area and its relation to regional synoptic systems

Natural Hazards and Earth System Science ◽

10.5194/nhess-11-2125-2011 ◽

2011 ◽

Vol 11 (8) ◽

pp. 2125-2135 ◽

Cited By ~ 21

Author(s):

S. Shalev ◽

H. Saaroni ◽

T. Izsak ◽

Y. Yair ◽

B. Ziv

Keyword(s):

Spatial Distribution ◽

Mediterranean Sea ◽

Temporal Distribution ◽

Lightning Activity ◽

Eastern Coast ◽

Synoptic Situation ◽

Lightning Flash ◽

The Mediterranean ◽

Spatio Temporal ◽

Neighboring Area

Abstract. The spatio-temporal distribution of lightning flashes over Israel and the neighboring area and its relation to the regional synoptic systems has been studied, based on data obtained from the Israel Lightning Location System (ILLS) operated by the Israel Electric Corporation (IEC). The system detects cloud-to-ground lightning discharges in a range of ~500 km around central Israel (32.5° N, 35° E). The study period was defined for annual activity from August through July, for 5 seasons in the period 2004–2010. The spatial distribution of lightning flash density indicates the highest concentration over the Mediterranean Sea, attributed to the contribution of moisture as well as sensible and latent heat fluxes from the sea surface. Other centers of high density appear along the coastal plain, orographic barriers, especially in northern Israel, and downwind from the metropolitan area of Tel Aviv, Israel. The intra-annual distribution shows an absence of lightning during the summer months (JJA) due to the persistent subsidence over the region. The vast majority of lightning activity occurs during 7 months, October to April. Although over 65 % of the rainfall in Israel is obtained during the winter months (DJF), only 35 % of lightning flashes occur in these months. October is the richest month, with 40 % of total annual flashes. This is attributed both to tropical intrusions, i.e., Red Sea Troughs (RST), which are characterized by intense static instability and convection, and to Cyprus Lows (CLs) arriving from the west. Based on daily study of the spatial distribution of lightning, three patterns have been defined; "land", "maritime" and "hybrid". CLs cause high flash density over the Mediterranean Sea, whereas some of the RST days are typified by flashes over land. The pattern defined "hybrid" is a combination of the other 2 patterns. On CL days, only the maritime pattern was noted, whereas in RST days all 3 patterns were found, including the maritime pattern. It is suggested that atmospheric processes associated with RST produce the land pattern. Hence, the occurrence of a maritime pattern in days identified as RST reflects an "apparent RST". The hybrid pattern was associated with an RST located east of Israel. This synoptic type produced the typical flash maximum over the land, but the upper-level trough together with the onshore winds it induced over the eastern coast of the Mediterranean resulted in lightning activity over the sea as well, similar to that of CLs. It is suggested that the spatial distribution patterns of lightning may better identify the synoptic system responsible, a CL, an "active RST" or an "apparent RST". The electrical activity thus serves as a "fingerprint" for the synoptic situation responsible for its generation.

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First record of the Combtooth Blenny, Microlipophrys adriaticus (Steindachner & Kolombatovic, 1883) (Pisces, Blenniidae), for the Italian Ionian Sea

Check List ◽

10.15560/11.3.1646 ◽

2015 ◽

Vol 11 (3) ◽

pp. 1646 ◽

Cited By ~ 1

Author(s):

F. Tiralongo ◽

R. Baldacconi

Keyword(s):

Mediterranean Sea ◽

Black Sea ◽

Adriatic Sea ◽

First Record ◽

The Black Sea ◽

Ionian Sea ◽

Sea Of Marmara ◽

Limited Distribution ◽

The North ◽

The Mediterranean

Microlipophrys adriaticus (Steindachner & Kolombatovic, 1883) is an endemic blenny of the Mediterranean Sea. It is also known from the Sea of Marmara and the Black Sea. However, unlike other species of combtooth blennies, M. adriaticus is a fish with a limited distribution in Adriatic Sea, especially in the north, where it can be common. We report here the first record of this species from the waters of the Ionian Sea.

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Further spreading of the non-indigenous bryozoan Celleporaria brunnea in the Mediterranean Sea: port to port morphological variations

10.7287/peerj.preprints.1592 ◽

2015 ◽

Author(s):

Jasmine Ferrario ◽

Agnese Marchini ◽

Martina Marić ◽

Dan Minchin ◽

Anna Occhipinti-Ambrogi

Keyword(s):

Mediterranean Sea ◽

Western Mediterranean ◽

Indigenous Species ◽

Large Variability ◽

Morphometric Characters ◽

Morphological Variations ◽

The North ◽

Western Mediterranean Sea ◽

The Pacific ◽

The Mediterranean

The Pacific cheilostome bryozoan Celleporaria brunnea (Hincks, 1884), a non-indigenous species already known for the Mediterranean Sea, was recorded in 2013-2014 from nine Italian port localities (Genoa, Santa Margherita Ligure, La Spezia, Leghorn, Viareggio, Olbia, Porto Rotondo, Porto Torres and Castelsardo) in the North-western Mediterranean Sea; in 2014 it was also found for the first time in the Adriatic Sea, in the marina “Kornati”, Biograd na Moru (Croatia). In Italy, specimens of C. brunnea were found in 44 out of 105 samples (48% from harbour sites ad 52% from marinas). These data confirm and update the distribution of C. brunnea in the Mediterranean Sea, and provide evidence that recreational boating is a vector responsible for the successful spread of this species. Previous literature data have shown the existence of differences in orifice and interzooidal avicularia length and width among different localities of the invaded range of C. brunnea. Therefore, measurements of orifice and avicularia were assessed for respectively 30 zooids and 8 to 30 interzooidal avicularia for both Italian and Croatian localities, and compared with literature data, in order to verify the existence of differences in the populations of C. brunnea that could reflect the geographic pattern of its invasion range. Our data show high variability of orifice measures among and within localities: zooids with broader than long orifice coexisted with others displaying longer than broad orifice, or similar values for both length and width. The morphological variation of C. brunnea in these localities, and above all the large variability of samples within single localities or even within colonies poses questions on the reliability of such morphometric characters for inter and intraspecific evaluations.

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