Principle and implementations of a refracto-nephelo-turbidimeter for seawater measurements

International audienceSalinity and turbidity are two important seawater properties in physical oceanography. The study of physical oceanography requires a compact high-resolution in-situ salino-turbidimeter to measure these two parameters in different ocean zones. Refractometry has proved to be an effective method to measure seawater salinity with a high resolution. Previous studies have shown that the transmission and scattering of light in a turbid medium impact the light beam deviation measurements, which makes the combination of salinity and turbidity measurements with the same sample mandatory. In this paper, we analyze the requirements and challenges of a refracto-turbidimeter design from their measurement principles and correlations. According to these requirements, we propose a miniature refracto-nephelo-turbidimeter with a CCD, providing a salinity measurement resolution of 2 mg.kg-1 and a turbidity measurement resolution of 1 % of the measurement range. Based on this refracto-nephelo-turbidimeter, different embodiments are discussed to meet the different requirements for different ocean zones

Study of the origin and correction of compass measurement errors in Doppler current meters

Surface and subsurface currents are two of the Essential Climate Variables (ECVs) defined by the Global Climate Observing System (GCOS). In situ current measurements can be made by Eulerian methods with instruments on moorings fixed in space. These methods require the determination of two metrological quantities: the speed and the direction of the motion. Their measurement and calibration require the determination of reference velocities and the measure of the angular movement of seawater in relation to the measuring device, as well as of the measuring device in relation to a reference direction given by the magnetic North. This reference direction is determined by electronic compasses integrated into current meters and current profilers. Compasses are sensitive to their magnetic environment, and, therefore, to the objects and instruments that surround them. This publication describes experiments conducted with current meters and current profilers to measure the influence of different devices on the accuracy of their compass measurements. It gives some explanations about the origin of measurement errors and proposes solutions to correct or attenuate the defaults in direction measurements and the measured deviations. Correction formulas are given that can be applied to measured data. They allow the reduction of errors of several tens of degrees for data to be within the instrument’s specifications

International Quality-Controlled Ocean Database (IQuOD) v0.1: The Temperature Uncertainty Specification

Ocean temperature observations are crucial for a host of climate research and forecasting activities, such as climate monitoring, ocean reanalysis and state estimation, seasonal-to-decadal forecasts, and ocean forecasting. For all of these applications, it is crucial to understand the uncertainty attached to each of the observations, accounting for changes in instrument technology and observing practices over time. Here, we describe the rationale behind the uncertainty specification provided for all in situ ocean temperature observations in the International Quality-controlled Ocean Database (IQuOD) v0.1, a value-added data product served alongside the World Ocean Database (WOD). We collected information from manufacturer specifications and other publications, providing the end user with uncertainty estimates based mainly on instrument type, along with extant auxiliary information such as calibration and collection method. The provision of a consistent set of observation uncertainties will provide a more complete understanding of historical ocean observations used to examine the changing environment. Moving forward, IQuOD will continue to work with the ocean observation, data assimilation and ocean climate communities to further refine uncertainty quantification. We encourage submissions of metadata and information about historical practices to the IQuOD project and WOD

Développement et essais d'un salinomètre optique

International audienceSalinity is the essential parameter for ocean dynamics studies. Its definition and using in the equations used to calculate the thermodynamic properties of seawater, have been revised in 2010, opening the possibility of new sensors developments. In this context, NOSS (NKE Optical Salinity Sensor) has emerged as one of the first underwater instrument for in situ refractive index measurement in the past years open up the scope of possibilities to access to density parameter. This achievement is the fruit of the cooperation between several institutions and the fruit of several years of developments and trials. NOSS sensor has been designed to be deployed in coastal environment and open-ocean waters up to 2000 m, especially on profiling floats of the Argo network.</p

Role des larves de Lobesia botrana dans la dissemination de la pourriture grise de la vigne

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Transmission of Botrytis cinerea to grapes by grape berry moth larvae

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Role des larves de Lobesia botrana dans la dissemination de la pourriture grise de la vigne

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Mise en evidence de la vection des spores de Botrytis cinerea par les larves de Lobesia botrana

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Association of Botrytis cinerea with grape berry moth larvae

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Velocity Calibration of Doppler Current Profiler Transducers

Doppler current profilers are used in oceanography to measure oceanic circulation but also in hydrology to calculate the flow of rivers. They allow the retrieval of water mass profiles in terms of velocity and direction. Direction is obtained via an electronic compass and tilt sensors, while velocity is obtained by measuring Doppler pulse shifts back-scattered by particles located in water cells allocated along the instrument&rsquo;s measurement range. Current meters are usually tested in towing basins or hydrodynamic channels, but these facilities present limits in terms of the measurement range, particles concentration and time costs. This paper presents a novel method developed to test the trueness of these velocity measurements in the laboratory, along with the uncertainty of this test and the results obtained with current meters and stand-alone profilers. The method is based on the measurement of the frequency of pulses emitted by each transducer of the instrument independently, and on the simulation of received echoes by a variable frequency sinusoidal signal