scholarly journals Chlorophyll signatures and nutrient cycles in the Mediterranean Sea: a model sensitivity study to nitrogen and phosphorus atmospheric inputs

2007 ◽  
Vol 4 (2) ◽  
pp. 909-959 ◽  
Author(s):  
M. Pacciaroni ◽  
G. Crispi
Keyword(s):  
Large Scale ◽  
Eastern Mediterranean ◽  
Three Dimensional ◽  
Sensitivity Study ◽  
Nitrogen And Phosphorus ◽  
State Response ◽  
Atmospheric Depositions ◽  
The Mediterranean ◽  
Atmospheric Inputs ◽  
External Loads

Abstract. In this work, the relative importance of nitrogen and phosphorus, considered as external loads, on Mediterranean biogeochemical cycles is evaluated. Biomass concentrations are analysed considering the steady state response of the three-dimensional ECHYM model to three nitrogen and phosphorus atmospheric depositions, considered as continuous in time. After reaching stationary evolutions, chlorophyll surficial maps and vertical transects are compared with existing datasets, showing a good agreement at their large scale sampling. The distributions of nutrients within the biochemical compartments are analysed, highlighting, inside the Mediterranean oligotrophic environment, the role played by ultraplankton, the smaller phytoplankton compartment. For all the three different atmospheric loads, western primary production estimation is about twice than that in the eastern basin, while western secondary production is about three times the eastern one. This numerical exercise suggests that the Eastern Mediterranean, cycling at low nutrient sill, is eventually pushed toward an higher nutrient depletion, when loading new nitrogen and phosphorus.

scholarly journals Rheological profiles in the Central- Eastern Mediterranean

1997 ◽  
Vol 40 (4) ◽  
Author(s):  
M. Viti ◽  
D. Albarello ◽  
E. Mantovani
Keyword(s):  
Heat Flow ◽  
Large Scale ◽  
Eastern Mediterranean ◽  
Mediterranean Area ◽  
Geological Time ◽  
Western Turkey ◽  
Geological Time Scale ◽  
Total Strength ◽  
The Mediterranean ◽  
Wet Rocks

Seismological investigations have provided an estimate of the gross structnral features of the crust/upper mantle system in the Mediterranean area. However, this information is only representative of the short-term me- chanical behaviour of rocks and cannot help us to understand slow deformations and related tectonic processes on the geological time scale. In this work strength envelopes for several major structural provinces of the Mediterranean area have been tentatively derived from seismological stratification and heat flow data, on the assumption of constant and uniforrn strain rate (10-16 S-1), wet rocks and conductive geotherm. It is also shown how the uncertainties in the reconstruction of thermal profiles can influence the main rheological prop- erties of the lithosphere, as thickness and total strength. The thickest (50-70 km) and strongest mechanical lithospheres correspond to the coldest zones (with heat flow lower than or equal to 50 mW m-2), i.e., the Io- nian and Levantine mesozoic basins, the Adriatic and Eurasian foreland zones and NW Greece. Heat flows larger than 65 mW m-2, generally observed in extensional zones (Tyrrhenian, Sicily Channel, Northern Aegean, Macedonia and Western Turkey), are mostly related to mechanical lithospheres thinner than 20 km. The characteristics of strength envelopes, and in particular the presence of soft layers in the crust, suggest a reasonable interpretation of some large-scale features which characterize the tectonic evolution of the Central- Eastem Mediterranean.

scholarly journals Hidden geographies of the ‘Mediterranean migration crisis’

2020 ◽  
pp. 239965442093590
Author(s):  
Vicki Squire
Keyword(s):  
Social Movement ◽  
Large Scale ◽  
Eastern Mediterranean ◽  
Critical Dimension ◽  
Migration Forms ◽  
Historical Dynamics ◽  
The Mediterranean ◽  
Political Act ◽  
Migration Crisis ◽  
Mediterranean Migration

This article explores the hidden geographies of what has been widely referred to as the ‘Mediterranean migration crisis’ of 2015 and 2016. Specifically, it draws on a large-scale analysis of migratory testimonies from across the central and eastern Mediterranean routes, in order to explore the claims or demands posed to European policy-makers by people on the move. Reflecting on the idea that migration forms a subversive political act that disrupts spatialised inequalities and longer histories of power and violence, the article sets out the argument advanced by scholars of the autonomy of migration approach that migration forms a ‘social movement’ involving subjective acts of escape. It makes the case for a move beyond an abstract account of migration as a social movement, to emphasise the importance of an analysis that unpacks the concrete ways in which multiple ‘nonmovements’ expose the hidden geographies of the so-called ‘crisis’. In so doing, it draws attention to two specific ways in which migration forms a political act. First, the article highlights anti-colonial acts that contest the spatialised inequalities of global migration along with longer-standing historical dynamics of exploitation and dispossession that these implicate. Second, it highlights anti-war acts that reject securitised responses to cross-border migration along with longer-standing spatial and historical dynamics of masculinist violence. While imperceptibility remains a critical dimension of many migratory acts, the article concludes that paying attention to the perceptible claims to justice that subversive political acts of migration involve is crucial in understanding the distinct transformations put into motion by people on the move.

scholarly journals How to Record Current Events like an Archaeologist

2021 ◽  
pp. 1-8
Author(s):  
Matthew Magnani ◽  
Anatolijs Venovcevs ◽  
Stein Farstadvoll ◽  
Natalia Magnani
Keyword(s):  
Material Culture ◽  
Large Scale ◽  
Three Dimensional ◽  
Social Phenomena ◽  
Field Methods ◽  
State Response ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Current Events

ABSTRACT This article shows how to record current events from an archaeological perspective. With a case study from the COVID-19 pandemic in Norway, we provide accessible tools to document broad spatial and behavioral patterns through material culture as they emerge. Stressing the importance of ethical engagement with contemporary subjects, we adapt archaeological field methods—including geolocation, photography, and three-dimensional modeling—to analyze the changing relationships between materiality and human sociality through the crisis. Integrating data from four contributors, we suggest that this workflow may engage broader publics as anthropological data collectors to describe unexpected social phenomena. Contemporary archaeological perspectives, deployed in rapid response, provide alternative readings on the development of current events. In the presented case, we suggest that local ways of coping with the pandemic may be overshadowed by the materiality of large-scale corporate and state response.

scholarly journals Precipitation climatology over Mediterranean Basin from ten years of TRMM measurements

2008 ◽  
Vol 17 ◽  
pp. 87-91 ◽  
Author(s):  
A. V. Mehta ◽  
S. Yang
Keyword(s):  
Mediterranean Sea ◽  
Rainy Season ◽  
Mediterranean Region ◽  
Large Scale ◽  
Eastern Mediterranean ◽  
Tropical Rainfall Measuring Mission ◽  
Western Mediterranean ◽  
Sea Temperature ◽  
Maximum Rainfall ◽  
The Mediterranean

Abstract. Climatological features of mesoscale rain activities over the Mediterranean region between 5° W–40° E and 28° N–48° N are examined using the Tropical Rainfall Measuring Mission (TRMM) 3B42 and 2A25 rain products. The 3B42 rainrates at 3-hourly, 0.25°×0.25° spatial resolution for the last 10 years (January 1998 to July 2007) are used to form and analyze the 5-day mean and monthly mean climatology of rainfall. Results show considerable regional and seasonal differences of rainfall over the Mediterranean Region. The maximum rainfall (3–5 mm day−1) occurs over the mountain regions of Europe, while the minimum rainfall is observed over North Africa (~0.5 mm day−1). The main rainy season over the Mediterranean Sea extends from October to March, with maximum rainfall occurring during November–December. Over the Mediterranean Sea, an average rainrate of ~1–2 mm day−1 is observed, but during the rainy season there is 20% larger rainfall over the western Mediterranean Sea than that over the eastern Mediterranean Sea. During the rainy season, mesoscale rain systems generally propagate from west to east and from north to south over the Mediterranean region, likely to be associated with Mediterranean cyclonic disturbances resulting from interactions among large-scale circulation, orography, and land-sea temperature contrast.

scholarly journals Trends in Mediterranean gridded temperature extremes and large-scale circulation influences

2011 ◽  
Vol 11 (8) ◽  
pp. 2199-2214 ◽  
Author(s):  
D. Efthymiadis ◽  
C. M. Goodess ◽  
P. D. Jones
Keyword(s):  
Large Scale ◽  
Eastern Mediterranean ◽  
Temperature Extremes ◽  
Global Trends ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Rate Of Increase ◽  
The Mediterranean ◽  
Large Scale Atmospheric Circulation ◽  
Cold Extremes

Abstract. Two recently-available daily gridded datasets are used to investigate trends in Mediterranean temperature extremes since the mid-20th century. The underlying trends are found to be generally consistent with global trends of temperature and their extremes: cold extremes decrease and warm/hot extremes increase. This consistency is better manifested in the western part of the Mediterranean where changes are most pronounced since the mid-1970s. In the eastern part, a cooling is observed, with a near reversal in the last two decades. This inter-basin discrepancy is clearer in winter, while in summer changes are more uniform and the west-east difference is restricted to the rate of increase of warm/hot extremes, which is higher in central and eastern parts of the Mediterranean over recent decades. Linear regression and correlation analysis reveals some influence of major large-scale atmospheric circulation patterns on the occurrence of these extremes – both in terms of trend and interannual variability. These relationships are not, however, able to account for the most striking features of the observations – in particular the intensification of the increasing trend in warm/hot extremes, which is most evident over the last 15–20 yr in the Central and Eastern Mediterranean.

scholarly journals Hydrographic situation during cruise M84/3 and P414 (spring 2011) in the Mediterranean Sea

2013 ◽  
Vol 10 (6) ◽  
pp. 2399-2432 ◽  
Author(s):  
D. Hainbucher ◽  
A. Rubino ◽  
V. Cardin ◽  
T. Tanhua ◽  
K. Schroeder ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Large Scale ◽  
Water Mass ◽  
Eastern Mediterranean ◽  
Physical Parameters ◽  
Strait Of Gibraltar ◽  
Mass Properties ◽  
The Mediterranean ◽  
Geostrophic Velocities ◽  
Lebanese Coast

Abstract. Hydrography and large scale circulation observed in the Mediterranean Sea during the M84/3 and P414 cruises (April and June 2011, respectively) are presented. In contrast to most of the recent expeditions, which were limited to special areas of the basin, these two cruises, especially the M84/3, offered the opportunity of delineating a quasi-synoptic picture of the distribution of the relevant physical parameters through the whole Mediterranean. A section was observed from the Lebanese coast up to the Strait of Gibraltar. The focus of our analysis are the water mass properties, also in the context of the recently observed variability, and a comparison between the velocity fields observed using a vessel-mounted ADCP and those calculated from the observed density fields. Overall, a distribution of temperature, salinity, and geostrophic velocities emerges, which seems far from that observed before the beginning of the so-called "Eastern Mediterranean Transient", a major climatic shift in the hydrography and circulation of the Mediterranean Sea occurred at the end of 1980s. Here, our focus is a discussion of the observed water mass properties analysed through T–S diagrams and through an Optimum Multiparameter (OMP) analysis. Additionally, ADCP velocities are compared to geostrophic calculations.

On the measurement of the turbulent diffusivity of a large-scale magnetic field

2013 ◽  
Vol 717 ◽  
pp. 347-360 ◽  
Author(s):  
S. M. Tobias ◽  
F. Cattaneo
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Laboratory Experiments ◽  
Three Dimensional ◽  
Effective Diffusivity ◽  
Dimensional System ◽  
Two Dimensional ◽  
Electrically Conducting ◽  
State Response ◽  
Large Scale Magnetic Field

AbstractWe argue that a method developed by Ångström (Ann. Phys. Chem., vol. 114, 1861, pp. 513–530) to measure the thermal conductivity of solids can be adapted to determine the effective diffusivity of a large-scale magnetic field in a turbulent electrically conducting fluid. The method consists of applying an oscillatory source and measuring the steady-state response. We illustrate this method in a two-dimensional system. This geometry is chosen because it is possible to compare the results with independent methods that are restricted to two-dimensional flows. We describe two variants of this method: one (the ‘turbulent Ångström method’) that is better suited to laboratory experiments and a second (the ‘method of oscillatory sines’) that is effective for numerical experiments. We show that, if correctly implemented, all methods agree. Based on these results we argue that these methods can be extended to three-dimensional numerical simulations and laboratory experiments.

scholarly journals ​Impact of changes in rivers inputs during the last decades on the biogeochemistry of the eastern Mediterranean basin

2020 ◽  
Author(s):  
Rémi Pagès ◽  
Melika Baklouti ◽  
Nicloas Barrier ◽  
Camille Richon ◽  
Jean-Claude Dutay ◽  
...  
Keyword(s):  
Surface Layer ◽  
Mediterranean Sea ◽  
Mediterranean Basin ◽  
Large Scale ◽  
Eastern Mediterranean ◽  
Phosphate Availability ◽  
Eastern Mediterranean Basin ◽  
The Mediterranean ◽  
Long Term Impact ◽  
First Time

<p>The Mediterranean Sea (MS) is a semi-enclosed sea characterized by a zonal west-east gradient of oligotrophy, where microbial growth is controlled by phosphate availability in most situations. External inputs of nutrients including Gibraltar inputs, river inputs and atmospheric deposition are therefore of major importance for the biogeochemistry of the MS. The latter has long been considered to be driven mainly by nutrient exchanges at Gibraltar. However, recent studies indicate that river inputs significantly affect nutrients concentrations in the Mediterranean Sea, although their resulting impact on its biogeochemistry remains poorly understood. In this study, our aim was to help fill this knowledge gap by addressing the large-scale and long-term impact of variations in river inputs on the biogeochemistry of the Mediterranean Sea over the last decades, using a coupled physical- biogeochemical 3D model (NEMO-MED12/Eco3M-Med). As a first result, it has been shown by the model that the strong diminution (60%) of phosphate (PO4) in river inputs into the Mediterranean Sea since the end of the 1980s induced a significant lowering of PO4 availability in the sub-surface layer of the Eastern Mediterranean Basin (EMB). One of the main consequences of PO4 diminution is the rise, never previously documented, of dissolved organic carbon (DOC) concentrations in the surface layer (by 20% on average over the EMB). Another main result concerns the gradual deepening of the top of the phosphacline during the period studied, thus generating a shift between the top of the nitracline and the top of the phosphacline in the EMB. This shift has already been observed in situ and documented in literature, but we propose here a new explanation for its occurrence in the EMB. The last main result is the evidence of the decline in abundance and the reduction of size of copepods calculated by the model over the years 1985–2010, that could partially explain the reduction in size of anchovy and sardine recently recorded in the MS. In this study, it is shown for the first time that the variations in river inputs that occurred in the last decades may have significantly altered the biogeochemical cycles of two key elements (P and C), in particular in the EMB.</p>

The Role of Zonally Averaged Climate Change in Contributing to Intermodel Spread in CMIP5 Predicted Local Precipitation Changes

2020 ◽  
Vol 33 (3) ◽  
pp. 1141-1154 ◽  
Author(s):  
Chaim I. Garfinkel ◽  
Ori Adam ◽  
Efrat Morin ◽  
Yehoudah Enzel ◽  
Eilat Elbaum ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Large Scale ◽  
Eastern Mediterranean ◽  
The United States ◽  
Hadley Cell ◽  
Cmip5 Models ◽  
Upper Troposphere ◽  
The Mediterranean ◽  
Precipitation Changes ◽  
Tropical Upper Troposphere

AbstractWhile CMIP5 models robustly project drying of the subtropics and more precipitation in the tropics and subpolar latitudes by the end of the century, the magnitude of these changes in precipitation varies widely across models: for example, some models simulate no drying in the eastern Mediterranean while others simulate more than a 50% reduction in precipitation relative to the model-simulated present-day value. Furthermore, the factors leading to changes in local subtropical precipitation remain unclear. The importance of zonal-mean changes in atmospheric structure for local precipitation changes is explored in 42 CMIP5 models. It is found that up to half of the local intermodel spread over the Mediterranean, northern Mexico, East Asia, southern Africa, southern Australia, and southern South America is related to the intermodel spread in large-scale processes such as the magnitude of globally averaged surface temperature increases, Hadley cell widening, polar amplification, stabilization of the tropical upper troposphere, or changes in the polar stratosphere. Globally averaged surface temperature increases account for intermodel spread in land subtropical drying in the Southern Hemisphere but are not important for land drying adjacent to the Mediterranean. The factors associated with drying over the eastern Mediterranean and western Mediterranean differ, with stabilization of the tropical upper troposphere being a crucial factor for the former only. Differences in precipitation between the western and eastern Mediterranean are also evident on interannual time scales. In contrast, the global factors examined here are unimportant over most of the United States, and more generally over the interior of continents. Much of the rest of the spread can be explained by variations in local relative humidity, a proxy also for zonally asymmetric circulation and thermodynamic changes.

scholarly journals Hydrographic situation during cruise M84/3 and P414 (spring 2011) in the Mediterranean Sea

Ocean Science ◽  
2014 ◽  
Vol 10 (4) ◽  
pp. 669-682 ◽  
Author(s):  
D. Hainbucher ◽  
A. Rubino ◽  
V. Cardin ◽  
T. Tanhua ◽  
K. Schroeder ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Large Scale ◽  
Eastern Mediterranean ◽  
Acoustic Doppler Current Profiler ◽  
Velocity Fields ◽  
Physical Parameters ◽  
Large Scale Circulation ◽  
Modes Of Variability ◽  
Current Profiler ◽  
The Mediterranean

Abstract. Aspects of hydrography and large-scale circulation observed in the Mediterranean Sea during the M84/3 and P414 cruises (April and June 2011, respectively) are presented. In contrast to most of the recent expeditions, which were limited to special areas of the basin, these two cruises, especially the M84/3, offered the opportunity of delineating a quasi-synoptic picture of the distribution of the relevant physical parameters along a section extending through the whole Mediterranean, from the Lebanese coast up to the Strait of Gibraltar. The foci of our analysis are the observed water mass properties and velocity fields. The first are investigated through T–S diagrams and an optimum multiparameter (OMP) analysis and the results are discussed also in the context of recently identified modes of variability; the second are studied by comparing the velocity fields observed using a vessel-mounted Acoustic Doppler Current Profiler and those calculated from the observed density fields. Overall, a distribution of temperature, salinity and geostrophic velocities emerges, which is far from that observed before the beginning of the so-called "Eastern Mediterranean Transient", a major climatic shift in the hydrography and circulation of the Mediterranean Sea which began at the end of the 1980s. The picture which emerges helps to further address the complexity of long-term evolution of hydrography and large-scale circulation of the Mediterranean Sea.

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