8 research outputs found

    Argo data 1999-2019: two million temperature-salinity profiles and subsurface velocity observations from a global array of profiling floats.

    Get PDF
    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Wong, A. P. S., Wijffels, S. E., Riser, S. C., Pouliquen, S., Hosoda, S., Roemmich, D., Gilson, J., Johnson, G. C., Martini, K., Murphy, D. J., Scanderbeg, M., Bhaskar, T. V. S. U., Buck, J. J. H., Merceur, F., Carval, T., Maze, G., Cabanes, C., Andre, X., Poffa, N., Yashayaev, I., Barker, P. M., Guinehut, S., Belbeoch, M., Ignaszewski, M., Baringer, M. O., Schmid, C., Lyman, J. M., McTaggart, K. E., Purkey, S. G., Zilberman, N., Alkire, M. B., Swift, D., Owens, W. B., Jayne, S. R., Hersh, C., Robbins, P., West-Mack, D., Bahr, F., Yoshida, S., Sutton, P. J. H., Cancouet, R., Coatanoan, C., Dobbler, D., Juan, A. G., Gourrion, J., Kolodziejczyk, N., Bernard, V., Bourles, B., Claustre, H., D'Ortenzio, F., Le Reste, S., Le Traon, P., Rannou, J., Saout-Grit, C., Speich, S., Thierry, V., Verbrugge, N., Angel-Benavides, I. M., Klein, B., Notarstefano, G., Poulain, P., Velez-Belchi, P., Suga, T., Ando, K., Iwasaska, N., Kobayashi, T., Masuda, S., Oka, E., Sato, K., Nakamura, T., Sato, K., Takatsuki, Y., Yoshida, T., Cowley, R., Lovell, J. L., Oke, P. R., van Wijk, E. M., Carse, F., Donnelly, M., Gould, W. J., Gowers, K., King, B. A., Loch, S. G., Mowat, M., Turton, J., Rama Rao, E. P., Ravichandran, M., Freeland, H. J., Gaboury, I., Gilbert, D., Greenan, B. J. W., Ouellet, M., Ross, T., Tran, A., Dong, M., Liu, Z., Xu, J., Kang, K., Jo, H., Kim, S., & Park, H. Argo data 1999-2019: two million temperature-salinity profiles and subsurface velocity observations from a global array of profiling floats. Frontiers in Marine Science, 7, (2020): 700, doi:10.3389/fmars.2020.00700.In the past two decades, the Argo Program has collected, processed, and distributed over two million vertical profiles of temperature and salinity from the upper two kilometers of the global ocean. A similar number of subsurface velocity observations near 1,000 dbar have also been collected. This paper recounts the history of the global Argo Program, from its aspiration arising out of the World Ocean Circulation Experiment, to the development and implementation of its instrumentation and telecommunication systems, and the various technical problems encountered. We describe the Argo data system and its quality control procedures, and the gradual changes in the vertical resolution and spatial coverage of Argo data from 1999 to 2019. The accuracies of the float data have been assessed by comparison with high-quality shipboard measurements, and are concluded to be 0.002°C for temperature, 2.4 dbar for pressure, and 0.01 PSS-78 for salinity, after delayed-mode adjustments. Finally, the challenges faced by the vision of an expanding Argo Program beyond 2020 are discussed.AW, SR, and other scientists at the University of Washington (UW) were supported by the US Argo Program through the NOAA Grant NA15OAR4320063 to the Joint Institute for the Study of the Atmosphere and Ocean (JISAO) at the UW. SW and other scientists at the Woods Hole Oceanographic Institution (WHOI) were supported by the US Argo Program through the NOAA Grant NA19OAR4320074 (CINAR/WHOI Argo). The Scripps Institution of Oceanography's role in Argo was supported by the US Argo Program through the NOAA Grant NA15OAR4320071 (CIMEC). Euro-Argo scientists were supported by the Monitoring the Oceans and Climate Change with Argo (MOCCA) project, under the Grant Agreement EASME/EMFF/2015/1.2.1.1/SI2.709624 for the European Commission

    A linear perturbation model with physical optics approximation to recover inhomogeneous surface impedance

    No full text
    International audienceInverse electromagnetic scattering problems related to objects having inhomogeneous isotropic impedance boundaries are addressed by considering small impedance variations between a measured object and a reference one. For many non-destructive electromagnetic testing, the structure geometries are known and only coated materials properties variations from reference numerical model are of interest. Consequently, the scattered field and equivalent surface current of the reference object can be precisely evaluated. We use the Chu-Stratton integral equation to express the differences of scattered far field between the measured and reference configurations in terms of surface current variation. Physical Optics approximation is used to derive a model of these surface current variations and we keep the first order term to solve a linear inverse problem. Consequently, the surface impedance can be reconstructed by a minimum norm solution in the least squares sense. Some promising numerical results on spherical geometries are presented with fixed incidence and frequency, in bistatic configuration. © Institution of Engineering and Technology.All Rights Reserved

    Perturbative Reciprocal Formulation for Maxwell's Equations a First Approach

    No full text
    International audienceWe invests ale theoretically the elect field scattered by a manufactured object having inhomogeneous perturbations of electromagnetic material properties. A known objet haring the same geometry and homogeneous material properties is exploited as a reference. Hence only small variations from reference configuration are of interest. Starting from the Volumetric-Perturbative Reciprocal Theory (VPRT), we derive an expression of the relationship between the reference configuration (which is supposed perfectly knoll ni and the perturbed one in addition to the permittivity, we extend the VPRT to permeability perturbations and we derive the first order expression for axisymmetric objects having axisymmetric perturbations. The resulting formulation can he used in a direct way=, for example to propagate uncertainties, as vvell as to solve an inverse problem for example in non-destructive testing, applications

    Born approximation to evaluate the em field variation induced by materials properties perturbations

    No full text
    International audienceWe investigate theoretically the electromagnetic field scattered by a manufactured object having inhomogeneous perturbations of electromagnetic material properties. A well-known objet having the same geometry and homogeneous material properties is exploited as a reference. Hence only small variations from reference configuration are of interest. Starting from the Volumetric-Perturbative Reciprocal Theory (VPRT), we derive an expression of the relationship between the reference configuration (which is supposed perfectly known) and the perturbed one in addition to the permittivity, we extend the VPRT to permeability perturbations and we derive the first and second order expression. In the case of axisymmetric objects having axisymmetric perturbations, we derive a particular expression reducing the volume integral into surface one. The resulting formulation can be used in a direct way, for example to propagate uncertainties, as well as to solve an inverse problem for example in non-destructive testing applications. © 2018 IEEE

    Satisfaction Indicators Taking into Account the Measurement and Computation Uncertainties for the Comparison of Data in Electromagnetics: Motivations and Scheduled Tasks of the French National Working Group CDIIS

    No full text
    International audienceA national study of criteria able to provide a satisfaction indicator about the comparison of data from electromagnetic measurement and computation, taking into account their associated uncertainties, has been organized in the framework of a French Working Group of the GdR Ondes, called CDIIS (Com-paraison de Données entachées d'Incertitudes: Indicateurs de Satisfaction). This Working Group involves several industrial or academic research laboratories, including laboratories depending on governmental organisms. Four tasks have been defined: 1/ Identification of a set of satisfaction indicators. 2/ Identification of pertinent test cases in different application domains of elec-tromagnetics. 3/ Application of the above criteria on the test cases. 4/ Conclusions: which criterion is best adapted to a given electromagnetism problem. This paper deals with Task 1 and discusses the results of various indicators applied to a canonical RCS (Radar Cross Section) test case

    Argo Data 1999-2019 : two million temperature-salinity profiles and subsurface velocity observations from a global array of profiling floats

    No full text
    In the past two decades, the Argo Program has collected, processed, and distributed over two million vertical profiles of temperature and salinity from the upper two kilometers of the global ocean. A similar number of subsurface velocity observations near 1,000 dbar have also been collected. This paper recounts the history of the global Argo Program, from its aspiration arising out of the World Ocean Circulation Experiment, to the development and implementation of its instrumentation and telecommunication systems, and the various technical problems encountered. We describe the Argo data system and its quality control procedures, and the gradual changes in the vertical resolution and spatial coverage of Argo data from 1999 to 2019. The accuracies of the float data have been assessed by comparison with high-quality shipboard measurements, and are concluded to be 0.002 degrees C for temperature, 2.4 dbar for pressure, and 0.01 PSS-78 for salinity, after delayed-mode adjustments. Finally, the challenges faced by the vision of an expanding Argo Program beyond 2020 are discussed
    corecore