scholarly journals On Cyclonic Tracks over the Eastern Mediterranean

2010 ◽  
Vol 23 (19) ◽  
pp. 5243-5257 ◽  
Author(s):  
Helena A. Flocas ◽  
Ian Simmonds ◽  
John Kouroutzoglou ◽  
Kevin Keay ◽  
Maria Hatzaki ◽  
...  

Abstract In this study, an updated and extended climatology of cyclonic tracks affecting the eastern Mediterranean region is presented, in order to better understand the Mediterranean climate and its changes. This climatology includes intermonthly variations, classification of tracks according to their origin domain, dynamic and kinematic characteristics, and trend analysis. The dataset used is the 1962–2001, 2.5° × 2.5°, 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40). The identification and tracking of the cyclones was performed with the aid of the Melbourne University algorithm. It was verified that considerable intermonthly variations of track density occur in the eastern Mediterranean, consistent with previous studies for the entire Mediterranean, while further interesting new features have been revealed. The classification of the tracks according to their origin domain reveals that the vast majority originate within the examined area itself, mainly in the Cyprus area and the southeastern Aegean Sea, while the tracks that originate elsewhere most frequently enter from the west. Deeper cyclones follow the southwest track originating from the area between Algeria and the Atlas Mountains. A greater size characterizes the westerly tracks (southwest, northwest, and west), while the northwest tracks propagate faster over the study area. A negative trend of the track frequency was found on an annual basis that can be mostly attributed to the winter months, being associated with variations in the baroclinicity. This negative trend is more prominent for the westerly and northeasterly tracks, as well as for those originating in the northern part of the examined area.

Elements ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 171-176 ◽  
Author(s):  
Paraskevi Nomikou ◽  
Christian Hübscher ◽  
Steven Carey

The Christiana–Santorini–Kolumbo volcanic field in the South Aegean Sea (Greece) is one of the most important in Europe, having produced more than 100 explosive eruptions in the last 400,000 years. Its volcanic centers include the extinct Christiana Volcano and associated seamounts, Santorini caldera with its intracaldera Kameni Volcano, Kolumbo Volcano, and 24 other submarine cones of the Kolumbo chain. Earthquakes, volcanic eruptions, submarine mass wasting, neotectonics and gas releases from these centers pose significant geohazards to human populations and infrastructures of the Eastern Mediterranean region. Defining the geological processes and structures that contribute to these geohazards will provide an important framework to guide future monitoring and research activities aimed at hazard mitigation.


2020 ◽  
Author(s):  
Shuang Zhang ◽  
Christina Manning ◽  
Christopher Satow ◽  
Simon J Armitage ◽  
Simon Blockley

<p>The Eastern Mediterranean is an important region for understanding the late Quaternary, as there is evidence for a complex pattern of climatic and environmental change, influenced by orbital forcing and complex feedback mechanisms (Rohling et al., 2013). It is also a key region for examining the dispersal of humans out of Africa. Consequently, it is important to develop robust chronologies for palaeoclimatic, environmental and archaeological records in the region, to allow synchronisation, comparison and hypothesis testing. Tephrochronology is a vital tool for correlating such records, but the fine detail of the Eastern Mediterranean tephra depositional history is not yet well defined. Part of the problem relates to a lack of cryptotephra (non-visible ash) studies on long stratigraphic records. It is well known from the Atlantic and Central Mediterranean that cryptotephra studies can significantly improve tephra inventories, and constrain the relationship between key tephra markers and important environmental transitions. Another key problem for the region is that for distal tephra there is a relatively limited geochemical database from different volcanic centres, especially in terms of trace element compositions. One important method for addressing this problem is to develop detailed tephrostratigraphic records and tephra geochemical inventories from long sediment sequences (e.g. Bourne et al., 2010; Satow et al., 2015).</p><p>Here we present the first marine crypto-tephrostratigraphy from the Levantine Sea, covering approximately the last ~200,000 years, from a long marine core (MD81-LC31). The new data for the core include tephra shard concentrations, major and trace element geochemistry, correlations to the eruptive record of the Aegean and Anatolian volcanic centres, and new radiometric age information. Our new data is compared to existing chronological information from LC-31, including sedimentological, geochemical, paleomagnetic and radiocarbon evidence. Our data helps to refine the chronology for this important record and will underpin ongoing studies into the detail of palaeoceanographic and environmental change in the region.</p><p> </p><p>Bourne, A.J., Lowe, J.J., Trincardi, F. et al. 2010. Distal tephra record for the last ca 105,000 years from core PRAD 1-2 in the central Adriatic Sea: implications for marine tephrostratigraphy. Quaternary Science Reviews, 29(23-24), 3079-3094.</p><p>Rohling, E.J., Grant, K.M., Roberts, A.P. et al. 2013. Paleoclimate variability in the Mediterranean and Red Sea regions during the last 500,000 years: implications for hominin migrations. Current Anthropology, 54(S8), S183-S201.</p><p>Satow, C., Tomlinson, E.L., Grant, K.M. et al. 2015. A new contribution to the Late Quaternary tephrostratigraphy of the Mediterranean: Aegean Sea core LC21. Quaternary Science Reviews, 117, 96-112.</p>


2009 ◽  
Vol 9 (4) ◽  
pp. 1299-1306 ◽  
Author(s):  
A. Papadopoulos ◽  
P. Katsafados

Abstract. The POSEIDON weather forecasting system became operational at the Hellenic Centre for Marine Research (HCMR) in October 1999. The system with its nesting capability provided 72-h forecasts in two different model domains, i.e. 25- and 10-km grid spacing. The lower-resolution domain covered an extended area that included most of Europe, Mediterranean Sea and N. Africa, while the higher resolution domain focused on the Eastern Mediterranean. A major upgrade of the system was recently implemented in the framework of the POSEIDON-II project (2005–2008). The aim was to enhance the forecasting skill of the system through improved model parameterization schemes and advanced numerical techniques for assimilating available observations to produce high resolution analysis fields. The configuration of the new system is applied on a horizontal resolution of 1/20°×1/20° (~5 km) covering the Mediterranean basin, Black Sea and part of North Atlantic providing up to 5-day forecasts. This paper reviews and compares the current with the previous weather forecasting systems at HCMR presenting quantitative verification statistics from the pre-operational period (from mid-November 2007 to October 2008). The statistics are based on verification against surface observations from the World Meteorological Organization (WMO) network across the Eastern Mediterranean region. The results indicate that the use of the new system can significantly improve the weather forecasts.


2020 ◽  
Author(s):  
Matthew Herman ◽  
Rob Govers ◽  
Lukas van de Wiel ◽  
Nicolai Nijholt

<p>The Aegean Sea region sits in a complex deformation zone between the African, Eurasian, and Anatolian plates. It contains the Hellenic subduction zone, where African oceanic lithosphere descends under the Aegean Sea. The subducting slab may be torn or fragmented at both its eastern (Pliny-Strabo zone) and western (Kefalonia fault) edges. The overriding Aegean Sea is cut by numerous active normal faults accommodating north-south extension. On top of this, the collision of Arabia with Anatolia farther east drives Anatolia and the connected Aegean Sea westward, resulting in the left lateral North Anatolian fault (and its extension into the Aegean), as well as greater relative velocities between the subducting slab and the overriding plate. These geodynamic processes and geological features all affect the present-day kinematics of the Aegean region.</p><p>Surface velocities measured at Global Navigation Satellite System stations throughout the Aegean provide important constraints on these underlying geodynamic forces. Previous studies have attributed the surface motions to some combination of plate boundary interactions, lateral variations in gravitational potential energy (GPE), subduction and slab tearing, internal faulting, and mantle tractions. The expected imprint of these processes also varies with the rheology of the lithosphere. Up to this point, there has been little effort to systematically evaluate the relative contributions of these different forces. In this study, we implement a Markov Chain Monte Carlo approach to efficiently and precisely determine the likely values and uncertainties of these geodynamic forces and the lithospheric rheology. We also identify trade-offs between processes that produce similar surface signals.</p><p>Preliminary results indicate that the dominant imprint on surface velocities comes from the southwestward rollback of the Hellenic slab and the westward escape of Anatolia. Although lateral variations in GPE also have an effect on the velocities, these are generally less important than slab rollback and Anatolian escape. At a lithospheric scale, the North Anatolian fault has little shear resistance to allow a relatively sharp velocity transition across it. Including resistive tractions on intraplate faults within the Aegean Sea has a smaller effect on the modeled velocity field. By using the velocity field to guide a statistical analysis of the geodynamic drivers, we have been able to better constrain the primary drivers of deformation in the eastern Mediterranean.</p>


Author(s):  
I.G.C. Kerr ◽  
J.M. Williams ◽  
W.D. Ross ◽  
J.M. Pollard

The European rabbit (Oryctolagus cuniculus) introduced into New Zealand in the 183Os, has consistently flourished in Central Otago, the upper Waitaki, and inland Marlborough, all areas of mediterranean climate. It has proved difficult to manage in these habitats. The 'rabbit problem' is largely confined to 105,000 ha of low producing land mostly in semi arid areas of Central Otago. No field scale modifications of the natural habitat have been successful in limiting rabbit numbers. The costs of control exceed the revenue from the land and continued public funding for control operations appears necessary. A system for classifying land according to the degree of rabbit proneness is described. Soil survey and land classification information for Central Otago is related to the distribution and density of rabbits. This intormation can be used as a basis for defining rabbit carrying capacity and consequent land use constraints and management needs. It is concluded that the natural rabbit carrying capacity of land can be defined by reference to soil survey information and cultural modification to the natural vegetation. Classification of land according to rabbit proneness is proposed as a means of identifying the need for, and allocation of, public funding tor rabbit management. Keywords: Rabbit habitat, rabbit proneness, use of rabbit prone land.


Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 503
Author(s):  
Ali Rostami ◽  
Seyed Mohammad Riahi ◽  
Vahid Fallah Omrani ◽  
Tao Wang ◽  
Andreas Hofmann ◽  
...  

Toxascaris leonina is an ascaridoid nematode of dogs and cats; this parasite affects the health of these animals. This study estimated the global prevalence of Ta. leonina infection in dogs and cats using random effects meta-analysis as well as subgroup, meta-regression and heterogeneity analyses. The data were stratified according to geographical region, the type of dogs and cats and environmental variables. A quantitative analysis of 135 published studies, involving 119,317 dogs and 25,364 cats, estimated prevalence rates of Ta. leonina in dogs and cats at 2.9% and 3.4%, respectively. Prevalence was highest in the Eastern Mediterranean region (7.2% for dogs and 10.0% for cats) and was significantly higher in stray dogs (7.0% vs. 1.5%) and stray cats (7.5% vs. 1.8%) than in pets. The findings indicate that, worldwide, ~26 million dogs and ~23 million cats are infected with Ta. leonina; these animals would shed substantial numbers of Ta. leonina eggs into the environment each year and might represent reservoirs of infection to other accidental or paratenic hosts. It is important that populations of dogs and cats as well as other canids and felids be monitored and dewormed for Ta. leonina and (other) zoonotic helminths.


Sign in / Sign up

Export Citation Format

Share Document