scholarly journals Relative dispersion in the South Western Mediterranean as derived from satellite-tracked surface drifting buoys

2017 ◽  
Author(s):  
Maher Bouzaiene ◽  
Milena Menna ◽  
Pierre-Marie Poulain ◽  
Dalila Elhmaidi
Keyword(s):  
Power Laws ◽  
Western Mediterranean ◽  
Linear Increase ◽  
Chaotic Advection ◽  
Relative Dispersion ◽  
Second Phase ◽  
The South ◽  
The Third ◽  
Initial Separation ◽  
Relative Diffusivity

Abstract. Relative dispersion (D2) in the South Western Mediterranean is analyzed using surface drifter pairs deployed during the period from 1986 to 2016. The results show the existence of four well-known regimes. The first regime, characterized by an exponential increment of the relative dispersion (Lundgren or exponential regime), corresponds to the chaotic advection at small scales and small separation distances, lasts for a few days. In the second regime, extending from 1.5 to roughly 7 days, for scales between 25 and 57 km and 1–3 km of initial distance, D2 increases as time cubed (Richardson regime). The third regime occurs for initial distances of 5–10 km and times of 1.5–13 days; D2 increases quadratically with time (Ballistic regime). The forth regime corresponds to time scales larger than 34 days for initial distances of 1–3 km and to 23 days for 35–40 km with a linear increase in time of D2 (Rayleigh or diffusive regime). The relative diffusivity and characteristic dispersion time exhibit three different phases based on the initial pair separations and corresponding with Lundgren, Richardson and Rayleigh regimes, respectively. In the first phase (enstrophy cascade range) the diffusivity is ~ D2 for distances smaller than 15 km and initial separation distances between 5 km and 10 km, and also for distances smaller than 40 km for initial separation distances between 35 km and 40 km; characteristic dispersion time is constant. In the second phase (inverse energy cascade), the diffusivity and characteristic dispersion time increase with growing distances following the 4/3 and 2/3 power laws, respectively, for scale ranging between 3 and 15 km and for initial distances smaller than 3 km. The third phase occurs for distance larger than 55 km, all pair velocities are uncorrelated and both relative diffusivity and characteristic dispersion time are approximately constants.

scholarly journals Turbulent dispersion properties from a model simulation of the western Mediterranean

2013 ◽  
Vol 10 (4) ◽  
pp. 1099-1125
Author(s):  
H. Nefzi ◽  
D. Elhmaidi ◽  
X. Carton
Keyword(s):  
Time Scale ◽  
Model Simulation ◽  
Western Mediterranean ◽  
Turbulent Dispersion ◽  
Chaotic Advection ◽  
Relative Dispersion ◽  
Integral Time Scale ◽  
Dispersion Properties ◽  
Integral Time ◽  
Relative Diffusivity

Abstract. Using a high resolution primitive equation model of the western Mediterranean Sea, we analyzed the dispersion properties of a set of homogeneously distributed, passive particle pairs. These particles were initially separated by different distances D0 (D0 = 5.55, 11.1 and 16.5 km), and were seeded in the model at initial depths of 44 and 500 m. This realistic ocean model, which reproduces the main features of the regional circulation, puts in evidence the three well-known regimes of relative dispersion. The first regime due to the chaotic advection at small scales, lasts only a few days (3 days at 44 m depth, a duration comparable with the integral time scale) and the relative dispersion is then exponential. In the second regime, extending from 3 to 20 days, the relative dispersion has a power law tα where α tends to 3 as D0 becomes small. In the third regime, a linear growth of the relative dispersion is observed starting from the twentieth day. For the relative diffusivity, the D2 growth is followed by the Richardson regime D4/3. At large scales, where particle velocities are decorrelated, the relative diffusivity is constant. At 500 m depth, the integral time scale increases (> 4 days) and the intermediate regime becomes narrower than that at 44 m depth due to weaker effect of vortices (this effect decreases with depth). The turbulent properties become less intermittent and more homogeneous and the Richardson law takes place.

scholarly journals Turbulent dispersion properties from a model simulation of the western Mediterranean Sea

Ocean Science ◽  
2014 ◽  
Vol 10 (2) ◽  
pp. 167-175
Author(s):  
H. Nefzi ◽  
D. Elhmaidi ◽  
X. Carton
Keyword(s):  
Mediterranean Sea ◽  
Model Simulation ◽  
Western Mediterranean ◽  
Ocean Model ◽  
Turbulent Dispersion ◽  
Chaotic Advection ◽  
Relative Dispersion ◽  
Dispersion Properties ◽  
Western Mediterranean Sea ◽  
Relative Diffusivity

Abstract. Using a high-resolution primitive equation model of the western Mediterranean Sea, we analyzed the dispersion properties of a set of homogeneously distributed, passive particle pairs. These particles were initially separated by different distances D0 (D0 = 5.55, 11.1 and 16.65 km), and were seeded in the model at initial depths of 44 and 500 m. This realistic ocean model, which reproduces the main features of the regional circulation, puts into evidence the three well-known regimes of relative dispersion. The first regime due to the chaotic advection at small scales lasts only a few days (3 days at 44 m depth, a duration comparable with the integral timescale), and the relative dispersion is then exponential. In the second regime, extending from 3 to 20 days, the relative dispersion has a power law tα where α tends to 3 as D0 becomes small. In the third regime, a linear growth of the relative dispersion is observed starting from the twentieth day. For the relative diffusivity, the D2 growth is followed by the Richardson regime D4/3. At large scales, where particle velocities are decorrelated, the relative diffusivity is constant. At 500 m depth, the integral timescale increases (> 4 days) and the intermediate regime becomes narrower than that at 44 m depth due to the weaker effect of vortices (this effect decreases with depth). The turbulent properties become less intermittent and more homogeneous and the Richardson law takes place.

New South African Review 3: The second phase – tragedy or farce? (John Daniel, Prishani Naidoo, Devan Pillay and Roger Southall, eds)

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Dirk Kotzé
Keyword(s):  
South Africa ◽  
South African ◽  
Social Practice ◽  
New South ◽  
Second Phase ◽  
Human Sciences ◽  
The South ◽  
Negotiated Settlement ◽  
The Third ◽  
Direct Competition

As the title indicates this publication is the third issue in a series of reviews. The first issue was subtitled 2010: Development or decline? (2010) and the second was New paths, old promises? (2011). These publications are edited in the Department of Sociology at Wits University as part of its Strategic Planning and Allocation of Resources Committee (SPARC) Programme. The series is intended to be a revival of the South African Review edited by the South African Research Service and published by Ravan Press in the 1980s and early 1990s. Arguably one of the best known of these series was issue seven edited by Steven Friedman and Doreen Atkinson, The Small Miracle: South Africa's negotiated settlement (1994). The latest publication should also be seen as direct competition for the Human Sciences Research Council's (HSRC) regular publication, State of the Nation. The New South African Review 3 is organised into four parts, namely Party, Power and Class; Ecology, Economy and Labour; Public Policy and Social Practice; and South Africa at Large. The four editors introduce each of the sections, consisting of 16 chapters in total. Thebook's format appears to be that of a yearbook but it is not linked to a specific year. It is therefore not in the same category as for example the South African Institute of Race Relations' annual South Africa Survey. The Review is organised around a theme, albeit very general in its formulation, and in the case of the third issue it is also not applicable to all its chapters. At the same time, though, it is not a yearbook as the choice of chapters and their foci are on the latest developments. 

Lagrangian Dispersion Characteristics in The Western Mediterranean

2018 ◽  
Vol 76 (5) ◽  
pp. 139-161 ◽  
Author(s):  
Maher Bouzaiene ◽  
Milena Menna ◽  
Pierre-Marie Poulain ◽  
Dalila Elhmaidi
Keyword(s):  
Separation Distance ◽  
Western Mediterranean ◽  
Small Time ◽  
Ocean Dynamics ◽  
Surface Velocity ◽  
Relative Dispersion ◽  
Dispersion Characteristics ◽  
Flow Topology ◽  
Initial Separation ◽  
Surface Drifters

Dispersion characteristics in the Western Mediterranean are analyzed using data from Coastal Ocean Dynamics Experiment (CODE) and Surface Velocity Program (SVP) surface drifters deployed in the period 1986–2017. Results are presented in terms of absolute dispersion A2 (mean-squared displacement of drifter individuals) and of relative dispersion (D2; mean square separation distance of drifter pairs). Moreover, the dispersion characteristics are estimated for different initial separation distances (D0) between particles: smaller, larger, or comparable with the internal Rossby radius of deformation. Results show the presence of a quasiballistic regime for absolute dispersion at small time scales and the nonlocal relative dispersion regime related to the submesoscale activities for scales smaller than the internal Rossby radius. At intermediate times, two anomalous absolute dispersion regimes (elliptic and hyperbolic regimes) related with the flow topology are observed, although the relative dispersion involves the Richardson and shear/ballistic regimes only for D0 smaller than the Rossby radius. During the subsequent 20–30 days, absolute dispersion shows quasirandom walk regime and relative dispersion follows the diffusive regime for scales larger than 100 km for which pair velocities are uncorrelated.

Listening for the “Still Small Voice” of Mendelssohn’s Domestic Elijah

2015 ◽  
Vol 32 (1) ◽  
pp. 40-77
Author(s):  
Peter Mercer-Taylor
Keyword(s):  
Second Phase ◽  
Divine Presence ◽  
Final Phase ◽  
Public And Private ◽  
The Public ◽  
The Third ◽  
Interpretive Approach ◽  
Will To Live ◽  
Three Phases

The notion that there might be autobiographical, or personally confessional, registers at work in Mendelssohn’s 1846 Elijah has long been established, with three interpretive approaches prevailing: the first, famously advanced by Prince Albert, compares Mendelssohn’s own artistic achievements with Elijah’s prophetic ones; the second, in Eric Werner’s dramatic formulation, discerns in the aria “It is enough” a confession of Mendelssohn’s own “weakening will to live”; the third portrays Elijah as a testimonial on Mendelssohn’s relationship to the Judaism of his birth and/or to the Christianity of his youth and adulthood. This article explores a fourth, essentially untested, interpretive approach: the possibility that Mendelssohn crafts from Elijah’s story a heartfelt affirmation of domesticity, an expression of his growing fascination with retiring to a quiet existence in the bosom of his family. The argument unfolds in three phases. In the first, the focus is on that climactic passage in Elijah’s Second Part in which God is revealed to the prophet in the “still small voice.” The turn from divine absence to divine presence is articulated through two clear and powerful recollections of music that Elijah had sung in the oratorio’s First Part, a move that has the potential to reconfigure our evaluation of his role in the public and private spheres in those earlier passages. The second phase turns to Elijah’s own brief sojourn into the domestic realm, the widow’s scene, paying particular attention to the motivations that may have underlain the substantial revisions to the scene that took place between the Birmingham premiere and the London premiere the following year. The final phase explores the possibility that the widow and her son, the “surrogate family” in the oratorio, do not disappear after the widow’s scene, but linger on as “para-characters” with crucial roles in the unfolding drama.

PENERAPAN MODEL QUANTUM LEARNING UNTUK MENINGKATKAN HASIL BELAJAR AUTOCAD SISWA KELAS X TEKNIK PEMESINAN SMK NEGERI 1 STABAT

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Abdul Hasan Saragih
Keyword(s):  
Positive Response ◽  
Phase 1 ◽  
First Grade ◽  
Learning Model ◽  
Second Phase ◽  
Phase 2 ◽  
Phase 3 ◽  
The Third ◽  
Third Phase ◽  
Quantum Learning

This classroom research was conducted on the autocad instructions to the first grade of mechinary class of SMK Negeri 1 Stabat aiming at : (1) improving the student’ archievementon autocad instructional to the student of mechinary architecture class of SMK Negeri 1 Stabat, (2) applying Quantum Learning Model to the students of mechinary class of SMK Negeri 1 Stabat, arising the positive response to autocad subject by applying Quantum Learning Model of the students of mechinary class of SMK Negeri 1 Stabat. The result shows that (1) by applying quantum learning model, the students’ achievement improves significantly. The improvement ofthe achievement of the 34 students is very satisfactory; on the first phase, 27 students passed (70.59%), 10 students failed (29.41%). On the second phase 27 students (79.41%) passed and 7 students (20.59%) failed. On the third phase 30 students (88.24%) passed and 4 students (11.76%) failed. The application of quantum learning model in SMK Negeri 1 Stabat proved satisfying. This was visible from the activeness of the students from phase 1 to 3. The activeness average of the students was 74.31% on phase 1,81.35% on phase 2, and 83.63% on phase 3. (3) The application of the quantum learning model on teaching autocad was very positively welcome by the students of mechinary class of SMK Negeri 1 Stabat. On phase 1 the improvement was 81.53% . It improved to 86.15% on phase 3. Therefore, The improvement ofstudent’ response can be categorized good.

CONDITIONS FAVOURABLE FOR PROTECTION THE MARINE SHORE OF THE VISTULA SPIT AND SAMBIAN PENINSULA (THE BATIC SEA, KALININGRAD OBLAST) BY OFFSHORE DISPOSAL OF DREDGED MATERIAL

2017 ◽  
Author(s):  
Andrei Sokolov ◽  
Andrei Sokolov ◽  
Boris Chubarenko ◽  
Boris Chubarenko
Keyword(s):  
Dredged Material ◽  
Vistula Lagoon ◽  
Shore Protection ◽  
The South ◽  
The Third ◽  
Dumping Site ◽  
The North ◽  
Kaliningrad Oblast ◽  
Wind Actions ◽  
The Vistula Lagoon

Three dumping sites located at the south-eastern part of the Baltic Sea (Kaliningrad Oblast) at shallow depths are considered. The first one is located to the south of the Vistula Lagoon inlet in front of a permanently eroded open marine shore segment. The second one is located to the north of the Vistula Lagoon inlet, and is used now for disposing of dredged material extracted from the Kaliningrad Seaway Canal. The third dumping site is located near the northern shore of the Sambian Peninsula to the east of the Cape Gvardeijski and assigned for disposing the dredged material extracted from the fairway to the Pionerskij Port located nearby. The last site is planned to be used for disposing of dredged material from the future port that should be constructed there before the beginning of the FIFA World Cup 2018. All three dumping sites are located not far from the eroded segments of the shore. The question behind the study is: would it possible that disposed material will naturally transported from the damping site to the shore and accumulate there to protect it from erosion? A numerical hydrodynamic-transport 3D model (MIKE) was used to model sediment transport under different wind actions. The winds with the speed stronger than 15 m/s complete wash out disposed material from the dumping site and spreading it over the wide area with a negligible layer thickness. Winds of about 7-10 m/s transport material along the shore at a distance of few kilometers that may be useful for shore protection. The first location of the dumping site (to the south of the Vistula Lagoon inlet) looks very ineffective for potential protection the shore nearby. At the other hand, the second and especially the third locations are favorable for transport of disposed material to the shore, the most favorable conditions are at onshore or alongshore currents.

CONDITIONS FAVOURABLE FOR PROTECTION THE MARINE SHORE OF THE VISTULA SPIT AND SAMBIAN PENINSULA (THE BATIC SEA, KALININGRAD OBLAST) BY OFFSHORE DISPOSAL OF DREDGED MATERIAL

2017 ◽  
Author(s):  
Andrei Sokolov ◽  
Andrei Sokolov ◽  
Boris Chubarenko ◽  
Boris Chubarenko
Keyword(s):  
Dredged Material ◽  
Vistula Lagoon ◽  
Shore Protection ◽  
The South ◽  
The Third ◽  
Dumping Site ◽  
The North ◽  
Kaliningrad Oblast ◽  
Wind Actions ◽  
The Vistula Lagoon

Three dumping sites located at the south-eastern part of the Baltic Sea (Kaliningrad Oblast) at shallow depths are considered. The first one is located to the south of the Vistula Lagoon inlet in front of a permanently eroded open marine shore segment. The second one is located to the north of the Vistula Lagoon inlet, and is used now for disposing of dredged material extracted from the Kaliningrad Seaway Canal. The third dumping site is located near the northern shore of the Sambian Peninsula to the east of the Cape Gvardeijski and assigned for disposing the dredged material extracted from the fairway to the Pionerskij Port located nearby. The last site is planned to be used for disposing of dredged material from the future port that should be constructed there before the beginning of the FIFA World Cup 2018. All three dumping sites are located not far from the eroded segments of the shore. The question behind the study is: would it possible that disposed material will naturally transported from the damping site to the shore and accumulate there to protect it from erosion? A numerical hydrodynamic-transport 3D model (MIKE) was used to model sediment transport under different wind actions. The winds with the speed stronger than 15 m/s complete wash out disposed material from the dumping site and spreading it over the wide area with a negligible layer thickness. Winds of about 7-10 m/s transport material along the shore at a distance of few kilometers that may be useful for shore protection. The first location of the dumping site (to the south of the Vistula Lagoon inlet) looks very ineffective for potential protection the shore nearby. At the other hand, the second and especially the third locations are favorable for transport of disposed material to the shore, the most favorable conditions are at onshore or alongshore currents.

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