The Copernicus surface velocity platform drifter with barometer and reference sensor for temperature (SVP-BRST): genesis, design, and initial results

To support calibration and validation of satel- lite sea surface temperature (SST) retrievals, over 60 high- resolution SST (HRSST) drifting buoys were deployed at sea between 2012 and 2017. Their data record is reviewed here. It is confirmed that sea state and immersion depth play an important role in understanding the data collected by such buoys and that the SST sensors need adequate insu- lation. In addition, calibration verification of three recovered drifters suggests that the sensor drift is low, albeit negative at around −0.01 K year−1. However, the statistical significance of these results is limited, and the calibration procedure could not be exactly reproduced, introducing additional uncertain- ties into this drift assessment. Based on lessons learnt from these initial buoys, a new sensor package for the Surface Velocity Platform with Barometer (SVP-B) was designed to serve calibration of SST retrievals by European Union’s Copernicus satellites. The novel sensor package includes an HRSST sensor calibrated by a metrology laboratory. The sensor includes a pressure probe to monitor immersion depth in calm water and acquires SST data at 1 Hz over a 5 min in- terval every hour. This enables the derivation of mean SST as well as several percentiles of the SST distribution. The HRSST sensor is calibrated with an uncertainty better than 0.01 K. Analysis of the data collected by two prototypes de- ployed in the Mediterranean Sea shows that the buoys are able to capture small-scale SST variations. These variations are found to be smaller when the sea state is well mixed and when the buoys are located within eddy cores. This affects the drifter SST data representativeness, which is an aspect of importance for optimal use of these data

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

© 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

Sur la modification des propriétés des aimants produite par les effets de bord. Cas des aimants à champ uniforme et à gradient de champ

We show that the fringe field of a constant-gap magnet gives nearly the same effect as if the magnet is replaced by a fictitious magnet such that ∫ U(z) dz, measured along a line perpendicular to an entrance or an exit face, is the same for both magnets. This result may be generalized to n-type magnets, but with rather more complicated expressions. We extend the Cartan graphical construction to these magnets.Nous montrons que l'effet du champ de bord dans un aimant à entrefer constant est, très approximativement, le même que si l'aimant réel est remplacé par un aimant fictif parfait tel que ∫ H(z) dz, compté sur une perpendiculaire à une face, soit le même pour les deux aimants. Ce résultat est généralisable au cas des aimants à gradient de champ, mais à partir d'expressions un peu plus compliquées. Nous généralisons à ces aimants la construction graphique de Cartan

Teledetection et variations du phytobenthos intertidal

Densitometric analyses and airborne infrared photographs obtained from year to year, together with field observations, were employed to quantify the extent of fluctuations in the previously identified algal populations on various sites. Besides, spectroradiometric records of similar algal populations were also obtained. This study confirms the possibility to collect automatic and repetitive data with SPOT, satellite that will permit a control and management of intertidal seaweeds at a very large scale

L'analyse des données Spot simulées sur les marais tropicaux. L'exemple des îles du Saloum (Sénégal)

Belbeoch G., Diaw T., Loubersac L. L'analyse des données Spot simulées sur les marais tropicaux. L'exemple des îles du Saloum (Sénégal). In: Bulletin de l'Association de géographes français, N°489-490, 59e année, Août-décembre 1982. pp. 293-295

"PIX'ILES 90" : télédétection et milieux insulaires du Pacifique : approches intégrées = Remote sensing and insular environments in the Pacific : integrated approaches

Après deux années d'existence, la Station Polynésienne de Télédétection (S.P.T.) a envisagé de se doter d'un système d'archivage d'images et de créer une banque de données de télédétection. Après l'énoncé des intérêts d'une telle archive, on présente les différentes phases de mise en place du projet, soit : la définition et la mise en oeuvre d'une station informatique d'archivage, outil de base du système, la définition et la conception d'un logiciel global de traitement de données numériques qui intègre et alimente la base de données de télédétection. Le système d'archivage est opérationnel dans les locaux de la S.P.T. La phase de conception et de réalisation du logiciel global et de la base de données est en cours. Les perspectives attendues de ce système sont l'amélioration de la productivité concernant la fabrication de spatiocartes des îles de la Polynésie française et la constitution d'une base de connaissances plurithématiques dérivée de la base de données de télédétection. (Résumé d'auteur