Users Guide for LATEXtools

Users GuideThis guide presents the LATEXtools package of Matlab routines, designed for planning and performing oceanographic cruises with a Lagrangian sampling strategy

Impacts of meso-to submeso-scale features on the ocean circulation in the Coral Sea

International audienceAs part of the South Pacific subtropical gyre, the encounter of the South Equatorial Current (SEC)with the complex bottom topography and numerous islands of the southwest tropical Pacific resultsinto a series of zonal jets, flowing mainly westward off the tip of archipelagos. Moreover, themesoscale activity at basin scale is dominated by westward-propagating nonlinear eddies, with astrong impact on the ocean circulation, the mixing of water masses and tracers' distribution. Eddy-jet interactions are studied here with the data collected in September 2012 during theBIFURCATION cruise in the Coral Sea, under the auspices of SPICE (Southwest PacIfic OceanCirculation and Climate Experiment). We analyze and explain in situ data with the help of satellite-based remote sensing data (altimetry, SSS, SST, ocean color), and we estimate the mass transportbudget within the Coral Sea. We show that the mesoscale activity is a significant contributor to the0-600m transport estimates (5-10 Sv) and is essential for the interpretation of hydrologicalobservations. A specific mesoscale eddy is identified as responsible for the connection between theNorth Vanuatu Jet (NVJ) and the North Caledonian Jet (NCJ). By using a Lagrangian technique, weare able to confirm the long-term connection between the NVJ and the NCJ through mesoscaleactivity. At a smaller scale, our analysis shows that surface temperature and salinity gradients can beassociated with hydrodynamical submesoscale features depicted by Finite Size LyapunovExponents (FSLE). These structures can also be linked to the presence of diazotroph species, incontrast with the general oligotrophy of the area. This study offers interesting outlooks for the useof FSLE to study the distribution of biogeochemical elements

A Connectivity-Based Eco-Regionalization Method of the Mediterranean Sea

International audienceEcoregionalization of the ocean is a necessary step for spatial management of marine resources. Previous ecoregionalization efforts were based either on the distribution of species or on the distribution of physical and biogeochemical properties. These approaches ignore the dispersal of species by oceanic circulation that can connect regions and isolates others. This dispersal effect can be quantified through connectivity that is the probability, or time of transport between distinct regions. Here a new regionalization method based on a connectivity approach is described and applied to the Mediterranean Sea. This method is based on an ensemble of Lagrangian particle numerical simulations using ocean model outputs at 1/12u resolution. The domain is divided into square subregions of 50 km size. Then particle trajectories are used to quantify the oceanographic distance between each subregions, here defined as the mean connection time. Finally the oceanographic distance matrix is used as a basis for a hierarchical clustering. 22 regions are retained and discussed together with a quantification of the stability of boundaries between regions. Identified regions are generally consistent with the general circulation with boundaries located along current jets or surrounding gyres patterns. Regions are discussed in the light of existing ecoregionalizations and available knowledge on plankton distributions. This objective method complements static regionalization approaches based on the environmental niche concept and can be applied to any oceanic region at any scale

Comportamiento de colzas invernales frente a primaverales en Santa Rosa, La Pampa

El siguiente trabajo se realizó en el campo experimental de la Facultad de Agronomía de la Universidad Nacional de La Pampa, ubicado a 36° 46' de latitud sur, a 64° 16' de longitud oeste y a 210 msnm, en el ciclo 1996/97. El objetivo de este trabajo fue determinar el comportamiento de cultivares invernales frente a los cultivares primaverales que se encuentran actualmente en el mercado con la finalidad de detectar materiales invernales, que cumplan sus requerimientos ambientales en la región y como tales puedan potenciar el rendimiento, y garantizar un mejor comportamiento a frío. Se utilizó un diseño de bloques al azar donde se siguió el comportamiento fenológico de ocho cultivares de colza: Honk (invernal), lndol (invernal precoz), Liberty (invernal semiprecoz), Nolza 541 (primaveral), Nolza 53 (primaveral), Tomado (primaveral semiprecoz) Mari (primaveral semiprecoz), y Volean (primaveral precoz) en tres fechas de siembra. Se encontró que los cultivares invernales sembrados en fechas tempranas presentan un comportamiento igual o superior a los cultivares primaverales, no encontrándose el mismo resultado para fechas de siembra tardías, en donde los cultivares invernales no alcanzan la etapa reproductiva

L'industria dei contenuti digitali in Piemonte : evoluzione e tendenze

Sistema informativo delle attività produttive- Indice #3- Introduzione e sintesi del rapporto. La rilevanza del settore nell'economia contemporanea #5- Il settore dei contenuti digitali in Piemonte #17- Il contributo dei testimoni privilegiati alla discussione sul ruolo del digitale nell'industria dei contenuti in Piemonte #55- Bibliografia #6

Oceanic three-dimensional Lagrangian Coherent Structures: A study of a mesoscale eddy in the Benguela ocean region

We study three dimensional oceanic Lagrangian Coherent Structures (LCSs) in the Benguela region, as obtained from an output of the ROMS model. To do that we first compute Finite-Size Lyapunov exponent (FSLE) fields in the region volume, characterizing mesoscale stirring and mixing. Average FSLE values show a general decreasing trend with depth, but there is a local maximum at about 100 m depth. LCSs are extracted as ridges of the calculated FSLE fields. They present a "curtain-like" geometry in which the strongest attracting and repelling structures appear as quasivertical surfaces. LCSs around a particular cyclonic eddy, pinched off from the upwelling front are also calculated. The LCSs are confirmed to provide pathways and barriers to transport in and out of the eddy

On the influence of coastal mesoscale dynamics on the jellyfish trajectories and distributions

IMAGE DU MOIS AVISO: http://www.aviso.oceanobs.com/en/news/idm/2012/may-2012-jellyfish-on-the-move/print.html ** Résumé de la conférence: http://www.coastalt.eu/files/sandiegoworkshop11/5CA-WS_summary.pdfInternational audienceOceanic mesoscale plays a key role in modulating large-scale circulation, heat fluxes transfer and primary production enhancement. Such hydrodynamic processes are also crucial for jellyfish transport and distribution along the Mediterranean coastal areas. Investigating the relationships between jellyfish distribution and mesoscale hydrodynamic processes therefore provides a rational to understand the influence of such physical structures on the dynamics of regional ecosystems, at the interface between the open ocean and the continental shelf. Nevertheless, the high spatial and temporal variability associated with coastal mesoscale motions makes them difficult to study with sparse in-situ observations. Alternative options rely on developing methodologies based on the combination of multi-sensor platforms in conjunction with numerical simulations. In this respect, we use an advanced Lagrangian particle tracking code developed at LOPB (Marseille, France) to simulate jellyfish trajectories from both a 3D circulation regional model and currents derived from satellite observations. These are obtained by a high resolution altimetric current mapping tools developed at IMEDEA (Majorques, Spain). The large scale signals (~100 km) are removed by subtracting the gridded Sea Level Anomaly maps (AVISO) to improve along track data. In a second step, the residuals are submitted to an objective analysis scheme with correlation scales adjusted to smaller mesoscale and coastal dynamics. Our approach allows us to characterize the main mesoscale features and exchange between the Ligurian Sea and the Gulf of Lion and to infer possible main pathways of jellyfish trajectories

Settling velocity and total ammonia nitrogen leaching from commercial feed and faecal pellets of gilthead seabream (Sparus aurata L. 1758) and seabass (Dicentrarchus labrax L. 1758)

The physico-chemical characteristics of particulate wastes of Sparus aurata and Dicentrarchus labrax were investigted. Changes in dimensions, settling velocity and total ammonia nitrogen (TAN) leached from commercial feed pellets was investigated after soaking. Also, the settling velocity and TAN leached from faecal pellets of these fish were assessed at 15 and 25ºC. The settling velocity of feed pellets was influenced positively by pellet weight and negatively by immersion length as a result of changes in pellet dimensions after soaking. The settling velocity of faecal pellets was determined by pellet weight. The experimental design did not allow identifying any consistent effect of water temperature on settling velocity. TAN leaching over time from feed and faecal pellets was successfully explained by means of a first order kinetic equation. For feed pellets, water temperature significantly affected the speed of the process and the time at which the maximum TAN leached was reached, but did not influence the maximum TAN leached. Leaching was related to feed pellet size, so the smaller the pellet, the higher the leaching. TAN leaching from faecal pellets was greater per unit weight than in feed pellets. However neither water temperature nor fish species influenced on TAN leaching from faeces

Lateral diffusivity coefficients from the dynamics of a SF6 patch in a coastal environment

The dispersion of a patch of the tracer sulfur hexafluoride (SF6) is used to assess the lateral diffusivity in the coastal waters of the western part of the Gulf of Lion (GoL), northwestern Mediterranean Sea, during the Latex10 experiment (September 2010). Immediately after the release, the spreading of the patch is associated with a strong decrease of the SF6 concentrations due to the gas exchange from the ocean to the atmosphere. This has been accurately quantified, evidencing the impact of the strong wind conditions during the first days of this campaign. Few days after the release, as the atmospheric loss of SF6 decreased, lateral diffusivity coefficient at spatial scales of 10 km has been computed using two approaches. First, the evolution of the patch with time was combined with a diffusion-strain model to obtain estimates of the strain rate (γ = 2.5 10- 6 s- 1) and of the lateral diffusivity coefficient (Kh = 23.2 m2s− 1). Second, a steady state model was applied, showing Kh values similar to the previous method after a period of adjustment between 2 and 4.5 days. This implies that after such period, our computation of Kh becomes insensitive to the inclusion of further straining of the patch. Analysis of sea surface temperature satellite imagery shows the presence of a strong front in the study area. The front clearly affected the dynamics within the region and thus the temporal evolution of the patch. Our results are consistent with previous studies in open ocean and demonstrate the success and feasibility of those methods also under small-scale, rapidly-evolving dynamics typical of coastal environments

Multi-platform experiments, numerical simulations and data science techniques for generation of new altimetric products: focus on mesoscale and sub- mesoscale variability (MANATEE – OSTST proposal)

Trabajo presentado en la Ocean Surface Topography Science Team Meeting (OSTST), celebrada online del 19 al 23 de octubre de 2020