Search results for " WAVE"
showing 10 items of 2296 documents
A Comparison between Drifter and X-Band Wave Radar for Sea Surface Current Estimation
2016
This paper deals with exploitation of the wave radar system for sea surface current estimation in a coastal zone. In particular, we present the results of the processing of the radar data collected by an X-band marine radar installed in Capo Granitola site, which is located in the south-west part of Sicily, on 15 May 2015. The effectiveness of the data processing is analyzed by comparing the wave radar estimated sea surface current with that provided by the Lagrangian drifters along its movement trajectory. During the measurement campaign, three drifter releases are carried out and for each one the comparison is provided in terms of the mean error and standard deviation. In addition, we rep…
Time domain astronomy with the THESEUS satellite
2021
THESEUS is a medium size space mission of the European Space Agency, currently under evaluation for a possible launch in 2032. Its main objectives are to investigate the early Universe through the observation of gamma-ray bursts and to study the gravitational waves electromagnetic counterparts and neutrino events. On the other hand, its instruments, which include a wide field of view X-ray (0.3-5 keV) telescope based on lobster-eye focussing optics and a gamma-ray spectrometer with imaging capabilities in the 2-150 keV range, are also ideal for carrying out unprecedented studies in time domain astrophysics. In addition, the presence onboard of a 70 cm near infrared telescope will allow simu…
Insolation cycles as a major control equatorial Indian Ocean primary production
1997
Analysis of a continuous sedimentary record taken in the Maldives indicates that strong primary production fluctuations (70 to 390 grams of carbon per square meter per year) have occurred in the equatorial Indian Ocean during the past 910,000 years. The record of primary production is coherent and in phase with the February equatorial insolation, whereas it shows diverse phase behavior with δ 18 O, depending on the orbital frequency (eccentricity, obliquity, or precession) examined. These observations imply a direct control of productivity in the equatorial oceanic system by insolation. In the equatorial Indian Ocean, productivity is driven by the wind intensity of westerlies, which is rel…
Direct and transgenerational effects of an experimental heat wave on early life stages in a freshwater snail
2018
AbstractGlobal climate change imposes a serious threat to natural populations of many species. Estimates of the effects of climate change-mediated environmental stresses are, however, often based only on their direct effects on organisms, and neglect the potential transgenerational effects. We investigated whether high temperature (i.e. an experimental heat wave) that is known to reduce performance of adultLymnaea stagnalissnails affects their offspring through maternal effects. Specifically, we tested whether eggs and hatched juveniles are affected by maternal thermal environment, and how strong these effects are compared with direct effects of temperature on offspring. We examined the eff…
Coupling agent-based with equation-based models to study spatially explicit megapopulation dynamics
2018
International audience; The incorporation of the spatial heterogeneity of real landscapes into population dynamics remains extremely difficult. We propose combining equation-based modelling (EBM) and agent-based modelling (ABM) to overcome the difficulties classically encountered. ABM facilitates the description of entities that act according to specific rules evolving on various scales. However, a large number of entities may lead to computational difficulties (e.g., for populations of small mammals, such as voles, that can exceed millions of individuals). Here, EBM handles age-structured population growth, and ABM represents the spreading of voles on large scales. Simulations applied to t…
Improving the analysis of biogeochemical patterns associated with internal waves in the strait of Gibraltar using remote sensing images
2018
High Amplitude Internal Waves (HAIWs) are physical processes observed in the Strait of Gibraltar (the narrow channel between the Atlantic Ocean and the Mediterranean Sea). These internal waves are generated over the Camarinal Sill (western side of the strait) during the tidal outflow (toward the Atlantic Ocean) when critical hydraulic conditions are established. HAIWs remain over the sill for up to 4 h until the outflow slackens, being then released (mostly) towards the Mediterranean Sea. These have been previously observed using Synthetic Aperture Radar (SAR), which captures variations in surface water roughness. However, in this work we use high resolution optical remote sensing, with the…
Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave su…
2021
The authors acknowledge COST Action ES 1105 "CYANOCOST Cyanobacterial blooms and toxins in water resources: Occurrence impacts and management" and COST Action Global Change Biology ES 1201 NETLAKE -Networking Lake Observatories in Europe" for contributing to this study through networking and knowledge sharing with European experts in the field. We acknowledge the members of the Global Lake Ecological Observatory Network (GLEON) for their collaborative spirit and enthusiasm that inspired the grassroots effort of the EMLS. E.M. was supported by a grant from the Swiss State Secretariat for Education, Research and Innovation to Bas Ibelings and by supplementary funding from University of Geneva…
Self-organized dynamics in spatially structured populations
2001
Self-organization and pattern formation represent the emergence of order in temporal and spatial processes. Self-organization in population ecology is gaining attention due to the recent advances concerning temporal fluctuations in the population size of dispersal-linked subunits. We shall report that spatially structured models of population renewal promote the emergence of a complex power law order in spatial population dynamics. We analyse a variety of population models showing that self-organization can be identified as a temporal match in population dynamics among local units, and how the synchrony changes in time. Our theoretical results are concordant with analyses of population data…
An experimental heat wave changes immune defense and life history traits in a freshwater snail
2013
The predicted increase in frequency and severity of heat waves due to climate change is expected to alter disease dynamics by reducing hosts' ability to resist infections. This could take place via two different mechanisms: (1) through general reduction in hosts' performance under harsh environmental conditions and/or (2) through altered resource allocation that reduces expression of defense traits in order to maintain other traits. We tested these alternative hypotheses by measuring the effect of an experimental heat wave (25 vs. 15°C) on the constitutive level of immune defense (hemocyte concentration, phenoloxidase [PO]‐like activity, antibacterial activity of hemolymph), and life histor…
Sea water desalination and energy consumption: A case study of wave energy converters (WEC) to desalination applications in sicily
2016
Recent studies about interactions among energy and water are considered as a new field of research. As almost all energy generation processes require significant amounts of water, and water requires energy for treatment and transport, so these two resources are inextricably linked. The main aim of this work is a presentation of the use of renewable energy for desalination plants in Sicily: in particular exploitation of wave energy into electrical energy necessary for water treatment. Desalination is the most energy intensive water treatment technology but it could be solution for many problems in water supply for areas with chronic debt of water. The aim of this work is a description of a s…