Search results for "MARINE"

Spatio-temporal behaviour of the deep chlorophyll maximum in Mediterranean Sea: Development of a stochastic model for picophytoplankton dynamics

2013

In this paper, by using a stochastic reaction-diffusion-taxis model, we analyze the picophytoplankton dynamics in the basin of the Mediterranean Sea, characterized by poorly mixed waters. The model includes intraspecific competition of picophytoplankton for light and nutrients. The multiplicative noise sources present in the model account for random fluctuations of environmental variables. Phytoplankton distributions obtained from the model show a good agreement with experimental data sampled in two different sites of the Sicily Channel. The results could be extended to analyze data collected in different sites of the Mediterranean Sea and to devise predictive models for phytoplankton dynam…

Systems tracts and depositional sequences in a carbonate setting: a study of continuous outcrops from platform to basin at the scale of seismic lines

1991

Abstract The application of sequence stratigraphy concepts to carbonates is feasible and this paper presents an example of its successful application. The continuity and lateral extent of outcropping sedimentary sections observed at the scale of a seismic line from platform to basin in the Southern Vercors Plateau (western Alps, France) confirm the validity of sequence stratigraphy concepts when applied to carbonate depositional systems. From the stratal patterns displayed in outcrop, we determined that carbonate lowstand systems tracts are major components in the basin, even in the deep pelagic realm. Transgressive and highstand systems tracts are very thin, a response to starvation. In co…

Support for a Vraconnian Stage between the Albian sensu stricto and the Cenomanian (Cretaceous System)

2008

The geological scale for the middle Cretaceous currently used throughout the world was proposed by Alcide d'Orbigny in the XIXth century between the years 1842 and 1847 and establishes the succession of stages as Albian, Cenomanian and Turonian. In 1868 Renevier proposed that a supplemental chronostratigraphic division be intercalated between the Albian and the Cenomanian: the Vraconnian stage. This term was not generally accepted and after a period when it was referred to by Breistroffer (1936) as a substage constituting the upper part of the Albian, as an equivalent of the Stoliczkaia dispar ammonite Zone, its abandonment was "recommended" by the Conference on the Lower Cretaceous held in…

Effect of Wind Turbulence on Extreme Load Analysis of an Offshore Wind Turbine

2019

Abstract Evaluation of dynamic responses under extreme environmental conditions is important for the structural design of offshore wind turbines. Previously, a modified environmental contour method has been proposed to estimate extreme responses. In the method, the joint distribution of environmental variables near the cut-out wind speed is used to derive the critical environmental conditions for a specified return period, and the turbulence intensity (TI) of wind is assumed to be a deterministic value. To address more realistic wind conditions, this paper considers the turbulence intensity as a stochastic variable and investigates the impact on the modified environmental contour. Aerodynam…

Assessment of the embodied energy for manufacturing and laying a submarine outfall pipeline

2008

The Life Cycle Assessment (LCA) methodology was applied to a submarine outfall pipeline intended for the disposal of treated MWW in the South Tyrrhenian Sea, on Western Coast of Sicily. The pipe serves 115 thousands inhabitants; it is 3,1 km long with an outer diameter of 800 mm and is allocated in a submarine trench down to 18 m bsl. The pipe ends with a multiport diffuser with outer diameter 500 mm. The whole pipeline is made in HDPE and is statically stabilized by cast iron rings and concrete anchor blocks. From the detailed constructive project of the pipeline the most relevant items involved were drawn and the most important ones were selected, both as materials employed and as laying …

Shallow submarine gas manifestations in the Aegean Sea: preliminary catalogue and geochemical characterization

2017

The Aegean area, like other regions of intense geodynamic activity, is characterised by extensive geogenic degassing. Gas manifestations widespread on land are also very frequent underwater. The present study aims at producing a first catalogue of these manifestations together with the geochemical characterization of the emitted gases. Sixty-one samples at 21 different sites have been collected by diving up to 15 m depth, mainly along the south Aegean active volcanic arc (SAAVA). The sites displayed very different gas fluxes. Most of them showed a very sluggish gas bubbling while a few had spatially large and strong bubbling. The most intense manifestation has been found at Kos Island along…

Inhibition of B2 receptor internalization delays its dephosphorylation

1997

Sea surges at Monaco and Nice: present-day and future variability (1998-2100).

2018

Sea surges arerapid increase of the level of the sea under atmospheric conditions that could lead to coastal submersion havingstrong impacts especially for coastal towns of the French Riviera such as Nice and the principality of Monaco.Interannual variability of the highest surges at Monaco is robustly simulates by a linear regression usingbarometric conditions over [3-10°E]-[40-45°N] as a predictor. According to 15 global circulation models,highest surges at Monaco could stay stationary for two different climate change scenarios (RCP4.5 andRCP8.5).

Parametric Design of Sailing Hull Shapes

2006

The author presents an original algorithm aimed at automatically generating the hull shape of a sailing yacht starting from an initial set of parameters. The procedure consists of two steps. First one keel line and a Designed Water Line (DWL in the following) are faired according to a set of parameters, say length of water line, canoe body draft, stem angle and some adimensional coefficients. This information is then used to fair the hull surface, which must in turn fulfil more prerequisites (parameters like displaty cement, floatation area and related coefficients). The hull is defined by means of a B-spline surface, the fairing of which is ensured by allowing for all the imposed objective…

Europe's offshore winds assessed with synthetic aperture radar, ASCAT and WRF

2020

Europe's offshore wind resource mapping is part of the New European Wind Atlas (NEWA) international consortium effort. This study presents the results of analysis of synthetic aperture radar (SAR) ocean wind maps based on Envisat and Sentinel-1 with a brief description of the wind retrieval process and Advanced Scatterometer (ASCAT) ocean wind maps. The wind statistics at 10 and 100 m above mean sea level (a.m.s.l.) height using an extrapolation procedure involving simulated long-term stability over oceans are presented for both SAR and ASCAT. Furthermore, the Weather Research and Forecasting (WRF) offshore wind atlas of NEWA is presented. This has 3 km grid spacing with data …