Udaya Bhaskar T. V. S.

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Udaya Bhaskar
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T. V. S.

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  • Article
    More than 50 years of successful continuous temperature section measurements by the global expendable bathythermograph network, its integrability, societal benefits, and future
    (Frontiers Media, 2019-07-24) Goni, Gustavo J. ; Sprintall, Janet ; Bringas, Francis ; Cheng, Lijing ; Cirano, Mauro ; Dong, Shenfu ; Domingues, Ricardo ; Goes, Marlos Pereira ; Lopez, Hosmay ; Morrow, Rosemary ; Rivero, Ulises ; Rossby, H. Thomas ; Todd, Robert E. ; Trinanes, Joaquin ; Zilberman, Nathalie ; Baringer, Molly O. ; Boyer, Tim ; Cowley, Rebecca ; Domingues, Catia M. ; Hutchinson, Katherine ; Kramp, Martin ; Mata, Mauricio M. ; Reseghetti, Franco ; Sun, Charles ; Udaya Bhaskar, T. V. S. ; Volkov, Denis L.
    The first eXpendable BathyThermographs (XBTs) were deployed in the 1960s in the North Atlantic Ocean. In 1967 XBTs were deployed in operational mode to provide a continuous record of temperature profile data along repeated transects, now known as the Global XBT Network. The current network is designed to monitor ocean circulation and boundary current variability, basin-wide and trans-basin ocean heat transport, and global and regional heat content. The ability of the XBT Network to systematically map the upper ocean thermal field in multiple basins with repeated trans-basin sections at eddy-resolving scales remains unmatched today and cannot be reproduced at present by any other observing platform. Some repeated XBT transects have now been continuously occupied for more than 30 years, providing an unprecedented long-term climate record of temperature, and geostrophic velocity profiles that are used to understand variability in ocean heat content (OHC), sea level change, and meridional ocean heat transport. Here, we present key scientific advances in understanding the changing ocean and climate system supported by XBT observations. Improvement in XBT data quality and its impact on computations, particularly of OHC, are presented. Technology development for probes, launchers, and transmission techniques are also discussed. Finally, we offer new perspectives for the future of the Global XBT Network.
  • Article
    Real-time quality control of optical backscattering data from Biogeochemical-Argo floats
    (European Commission, 2022-10-13) Dall'Olmo, Giorgio ; Bhaskar TVS, Udaya ; Bittig, Henry ; Boss, Emmanuel ; Brewster, Jodi ; Claustre, Hervé ; Donnelly, Matt ; Maurer, Tanya ; Nicholson, David ; Paba, Violetta ; Plant, Josh ; Poteau, Antoine ; Sauzède, Raphaëlle ; Schallenberg, Christina ; Schmechtig, Catherine ; Schmid, Claudia ; Xing, Xiaogang
    Background: Biogeochemical-Argo floats are collecting an unprecedented number of profiles of optical backscattering measurements in the global ocean. Backscattering (BBP) data are crucial to understanding ocean particle dynamics and the biological carbon pump. Yet, so far, no procedures have been agreed upon to quality control BBP data in real time. Methods: Here, we present a new suite of real-time quality-control tests and apply them to the current global BBP Argo dataset. The tests were developed by expert BBP users and Argo data managers and have been implemented on a snapshot of the entire Argo dataset. Results: The new tests are able to automatically flag most of the “bad” BBP profiles from the raw dataset. Conclusions: The proposed tests have been approved by the Biogeochemical-Argo Data Management Team and will be implemented by the Argo Data Assembly Centres to deliver real-time quality-controlled profiles of optical backscattering. Provided they reach a pressure of about 1000 dbar, these tests could also be applied to BBP profiles collected by other platforms.
  • Article
    Heat content of the Arabian Sea Mini Warm Pool is increasing
    (John Wiley & Sons, 2015-11-18) Nagamani, P. V. ; Ali, M. M. ; Goni, Gustavo J. ; Udaya Bhaskar, T. V. S. ; McCreary, Julian P. ; Weller, Robert A. ; Rajeevan, Madhavan Nair ; Gopalakrishna, V. V. ; Pezzullo, John C.
    Sea surface temperature in the Arabian Sea Mini Warm Pool has been suggested to be one of the factors that affects the Indian summer monsoon. In this paper, we analyze the annual ocean heat content (OHC) of this region during 1993–2010, using in situ data, satellite observations, and a model simulation. We find that OHC increases significantly in the region during this period relative to the north Indian Ocean, and propose that this increase could have caused the decrease in Indian Summer Monsoon Rainfall that occurred at the same time.
  • Article
    Argo data 1999-2019: two million temperature-salinity profiles and subsurface velocity observations from a global array of profiling floats.
    (Frontiers Media, 2020-09-15) Wong, Annie P. S. ; Wijffels, Susan E. ; Riser, Stephen C. ; Pouliquen, Sylvie ; Hosoda, Shigeki ; Roemmich, Dean ; Gilson, John ; Johnson, Gregory C. ; Martini, Kim I. ; Murphy, David J. ; Scanderbeg, Megan ; Udaya Bhaskar, T. V. S. ; Buck, Justin J. H. ; Merceur, Frederic ; Carval, Thierry ; Maze, Guillaume ; Cabanes, Cécile ; André, Xavier ; Poffa, Noé ; Yashayaev, Igor ; Barker, Paul M. ; Guinehut, Stéphanie ; Belbeoch, Mathieu ; Ignaszewski, Mark ; Baringer, Molly O. ; Schmid, Claudia ; Lyman, John ; McTaggart, Kristene E. ; Purkey, Sarah G. ; Zilberman, Nathalie ; Alkire, Matthew ; Swift, Dana ; Owens, W. Brechner ; Jayne, Steven R. ; Hersh, Cora ; Robbins, Pelle E. ; West-Mack, Deb ; Bahr, Frank B. ; Yoshida, Sachiko ; Sutton, Philip J. H. ; Cancouët, Romain ; Coatanoan, Christine ; Dobbler, Delphine ; Garcia Juan, Andrea ; Gourrion, Jérôme ; Kolodziejczyk, Nicolas ; Bernard, Vincent ; Bourlès, Bernard ; Claustre, Hervé ; d’Ortenzio, Fabrizio ; Le Reste, Serge ; Le Traon, Pierre-Yves ; Rannou, Jean-Philippe ; Saout-Grit, Carole ; Speich, Sabrina ; Thierry, Virginie ; Verbrugge, Nathalie ; Angel-Benavides, Ingrid M. ; Klein, Birgit ; Notarstefano, Giulio ; Poulain, Pierre Marie ; Vélez-Belchí, Pedro ; Suga, Toshio ; Ando, Kentaro ; Iwasaska, Naoto ; Kobayashi, Taiyo ; Masuda, Shuhei ; Oka, Eitarou ; Sato, Kanako ; Nakamura, Tomoaki ; Sato, Katsunari ; Takatsuki, Yasushi ; Yoshida, Takashi ; Cowley, Rebecca ; Lovell, Jenny L. ; Oke, Peter ; van Wijk, Esmee ; Carse, Fiona ; Donnelly, Matthew ; Gould, W. John ; Gowers, Katie ; King, Brian A. ; Loch, Stephen G. ; Mowat, Mary ; Turton, Jon ; Pattabhi Rama Rao, Eluri ; Ravichandran, M. ; Freeland, Howard ; Gaboury, Isabelle ; Gilbert, Denis ; Greenan, Blair J. W. ; Ouellet, Mathieu ; Ross, Tetjana ; Tran, Anh ; Dong, Mingmei ; Liu, Zenghong ; Xu, Jianping ; Kang, KiRyong ; Jo, HyeongJun ; Kim, Sung-Dae ; Park, Hyuk-Min
    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.