Roemmich Dean

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Roemmich
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  • Article
    The Argo Program : observing the global ocean with profiling floats
    (Oceanography Society, 2009-06) Roemmich, Dean ; Johnson, Gregory C. ; Riser, Stephen C. ; Davis, Russ E. ; Gilson, John ; Owens, W. Brechner ; Garzoli, Silvia L. ; Schmid, Claudia ; Ignaszewski, Mark
    The Argo Program has created the first global array for observing the subsurface ocean. Argo arose from a compelling scientific need for climate-relevant ocean data; it was made possible by technology development and implemented through international collaboration. The float program and its data management system began with regional arrays in 1999, scaled up to global deployments by 2004, and achieved its target of 3000 active instruments in 2007. US Argo, supported by the National Oceanic and Atmospheric Administration and the Navy through the National Oceanographic Partnership Program, provides half of the floats in the international array, plus leadership in float technology, data management, data quality control, international coordination, and outreach. All Argo data are freely available without restriction, in real time and in research-quality forms. Uses of Argo data range from oceanographic research, climate research, and education, to operational applications in ocean data assimilation and seasonal-to-decadal prediction. Argo’s value grows as its data accumulate and their applications are better understood. Continuing advances in profiling float and sensor technologies open many exciting possibilities for Argo’s future, including expanding sampling into high latitudes and the deep ocean, improving near-surface sampling, and adding biogeochemical parameters.
  • Article
    An Argo mixed layer climatology and database
    (John Wiley & Sons, 2017-06-12) Holte, James ; Talley, Lynne D. ; Gilson, John ; Roemmich, Dean
    A global climatology and database of mixed layer properties are computed from nearly 1,250,000 Argo profiles. The climatology is calculated with both a hybrid algorithm for detecting the mixed layer depth (MLD) and a standard threshold method. The climatology provides accurate information about the depth, properties, extent, and seasonal patterns of global mixed layers. The individual profile results in the database can be used to construct time series of mixed layer properties in specific regions of interest. The climatology and database are available online at http://mixedlayer.ucsd.edu. The MLDs calculated by the hybrid algorithm are shallower and generally more accurate than those of the threshold method, particularly in regions of deep winter mixed layers; the new climatology differs the most from existing mixed layer climatologies in these regions. Examples are presented from the Labrador and Irminger Seas, the Southern Ocean, and the North Atlantic Ocean near the Gulf Stream. In these regions the threshold method tends to overestimate winter MLDs by approximately 10% compared to the algorithm.
  • Article
    The technological, scientific, and sociological revolution of global subsurface ocean observing
    (Oceanography Society, 2022-01-07) Roemmich, Dean ; Talley, Lynne D. ; Zilberman, Nathalie ; Osborne, Emily ; Johnson, Kenneth S. ; Barbero, Leticia ; Bittig, Henry C. ; Briggs, Nathan ; Fassbender, Andrea J. ; Johnson, Gregory C. ; King, Brian A. ; McDonagh, Elaine L. ; Purkey, Sarah G. ; Riser, Stephen C. ; Suga, Toshio ; Takeshita, Yuichiro ; Thierry, Virginie ; Wijffels, Susan E.
    The complementary partnership of the Global Ocean Ship-based Hydrographic Investigations Program (GO-SHIP; https://www.go-ship.org/) and the Argo Program (https://argo.ucsd.edu) has been instrumental in providing sustained subsurface observations of the global ocean for over two decades. Since the late twentieth century, new clues into the ocean’s role in Earth’s climate system have revealed a need for sustained global ocean observations (e.g., Gould et al., 2013; Schmitt, 2018) and stimulated revolutionary technology advances needed to address the societal mandate. Together, the international GO-SHIP and Argo Program responded to this need, providing insight into the mean state and variability of the physics, biology, and chemistry of the ocean that led to advancements in fundamental science and monitoring of the state of Earth's climate.
  • Article
    On the future of Argo: A global, full-depth, multi-disciplinary array
    (Frontiers Media, 2019-08-02) Roemmich, Dean ; Alford, Matthew H. ; Claustre, Hervé ; Johnson, Kenneth S. ; King, Brian ; Moum, James N. ; Oke, Peter ; Owens, W. Brechner ; Pouliquen, Sylvie ; Purkey, Sarah G. ; Scanderbeg, Megan ; Suga, Koushirou ; Wijffels, Susan E. ; Zilberman, Nathalie ; Bakker, Dorothee ; Baringer, Molly O. ; Belbeoch, Mathieu ; Bittig, Henry C. ; Boss, Emmanuel S. ; Calil, Paulo H. R. ; Carse, Fiona ; Carval, Thierry ; Chai, Fei ; Conchubhair, Diarmuid Ó. ; d’Ortenzio, Fabrizio ; Dall'Olmo, Giorgio ; Desbruyeres, Damien ; Fennel, Katja ; Fer, Ilker ; Ferrari, Raffaele ; Forget, Gael ; Freeland, Howard ; Fujiki, Tetsuichi ; Gehlen, Marion ; Geenan, Blair ; Hallberg, Robert ; Hibiya, Toshiyuki ; Hosoda, Shigeki ; Jayne, Steven R. ; Jochum, Markus ; Johnson, Gregory C. ; Kang, KiRyong ; Kolodziejczyk, Nicolas ; Körtzinger, Arne ; Le Traon, Pierre-Yves ; Lenn, Yueng-Djern ; Maze, Guillaume ; Mork, Kjell Arne ; Morris, Tamaryn ; Nagai, Takeyoshi ; Nash, Jonathan D. ; Naveira Garabato, Alberto C. ; Olsen, Are ; Pattabhi Rama Rao, Eluri ; Prakash, Satya ; Riser, Stephen C. ; Schmechtig, Catherine ; Schmid, Claudia ; Shroyer, Emily L. ; Sterl, Andreas ; Sutton, Philip J. H. ; Talley, Lynne D. ; Tanhua, Toste ; Thierry, Virginie ; Thomalla, Sandy J. ; Toole, John M. ; Troisi, Ariel ; Trull, Thomas W. ; Turton, Jon ; Velez-Belchi, Pedro ; Walczowski, Waldemar ; Wang, Haili ; Wanninkhof, Rik ; Waterhouse, Amy F. ; Waterman, Stephanie N. ; Watson, Andrew J. ; Wilson, Cara ; Wong, Annie P. S. ; Xu, Jianping ; Yasuda, Ichiro
    The Argo Program has been implemented and sustained for almost two decades, as a global array of about 4000 profiling floats. Argo provides continuous observations of ocean temperature and salinity versus pressure, from the sea surface to 2000 dbar. The successful installation of the Argo array and its innovative data management system arose opportunistically from the combination of great scientific need and technological innovation. Through the data system, Argo provides fundamental physical observations with broad societally-valuable applications, built on the cost-efficient and robust technologies of autonomous profiling floats. Following recent advances in platform and sensor technologies, even greater opportunity exists now than 20 years ago to (i) improve Argo’s global coverage and value beyond the original design, (ii) extend Argo to span the full ocean depth, (iii) add biogeochemical sensors for improved understanding of oceanic cycles of carbon, nutrients, and ecosystems, and (iv) consider experimental sensors that might be included in the future, for example to document the spatial and temporal patterns of ocean mixing. For Core Argo and each of these enhancements, the past, present, and future progression along a path from experimental deployments to regional pilot arrays to global implementation is described. The objective is to create a fully global, top-to-bottom, dynamically complete, and multidisciplinary Argo Program that will integrate seamlessly with satellite and with other in situ elements of the Global Ocean Observing System (Legler et al., 2015). The integrated system will deliver operational reanalysis and forecasting capability, and assessment of the state and variability of the climate system with respect to physical, biogeochemical, and ecosystems parameters. It will enable basic research of unprecedented breadth and magnitude, and a wealth of ocean-education and outreach opportunities.
  • Article
    Measuring global ocean heat content to estimate the Earth energy Imbalance
    (Frontiers Media, 2019-08-20) Meyssignac, Benoit ; Boyer, Tim ; Zhao, Zhongxiang ; Hakuba, Maria Z. ; Landerer, Felix ; Stammer, Detlef ; Kohl, Armin ; Kato, Seiji ; L’Ecuyer, Tristan S. ; Ablain, Michaël ; Abraham, John Patrick ; Blazquez, Alejandro ; Cazenave, Anny ; Church, John A. ; Cowley, Rebecca ; Cheng, Lijing ; Domingues, Catia M. ; Giglio, Donata ; Gouretski, Viktor ; Ishii, Masayoshi ; Johnson, Gregory C. ; Killick, Rachel E. ; Legler, David ; Llovel, William ; Lyman, John ; Palmer, Matthew D. ; Piotrowicz, Stephen R. ; Purkey, Sarah G. ; Roemmich, Dean ; Roca, Rémy ; Savita, Abhishek ; von Schuckmann, Karina ; Speich, Sabrina ; Stephens, Graeme ; Wang, Gongjie ; Wijffels, Susan E. ; Zilberman, Nathalie
    The energy radiated by the Earth toward space does not compensate the incoming radiation from the Sun leading to a small positive energy imbalance at the top of the atmosphere (0.4–1 Wm–2). This imbalance is coined Earth’s Energy Imbalance (EEI). It is mostly caused by anthropogenic greenhouse gas emissions and is driving the current warming of the planet. Precise monitoring of EEI is critical to assess the current status of climate change and the future evolution of climate. But the monitoring of EEI is challenging as EEI is two orders of magnitude smaller than the radiation fluxes in and out of the Earth system. Over 93% of the excess energy that is gained by the Earth in response to the positive EEI accumulates into the ocean in the form of heat. This accumulation of heat can be tracked with the ocean observing system such that today, the monitoring of Ocean Heat Content (OHC) and its long-term change provide the most efficient approach to estimate EEI. In this community paper we review the current four state-of-the-art methods to estimate global OHC changes and evaluate their relevance to derive EEI estimates on different time scales. These four methods make use of: (1) direct observations of in situ temperature; (2) satellite-based measurements of the ocean surface net heat fluxes; (3) satellite-based estimates of the thermal expansion of the ocean and (4) ocean reanalyses that assimilate observations from both satellite and in situ instruments. For each method we review the potential and the uncertainty of the method to estimate global OHC changes. We also analyze gaps in the current capability of each method and identify ways of progress for the future to fulfill the requirements of EEI monitoring. Achieving the observation of EEI with sufficient accuracy will depend on merging the remote sensing techniques with in situ measurements of key variables as an integral part of the Ocean Observing System.
  • 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.
  • Article
    Heat stored in the Earth system: where does the energy go?
    (Copernicus Publications, 2020-09-07) von Schuckmann, Karina ; Cheng, Lijing ; Palmer, Matthew D. ; Hansen, James ; Tassone, Caterina ; Aicher, Valentin ; Adusumilli, Susheel ; Beltrami, Hugo ; Boyer, Tim ; Cuesta-Valero, Francisco José ; Desbruyeres, Damien ; Domingues, Catia M. ; García-García, Almudena ; Gentine, Pierre ; Gilson, John ; Gorfer, Maximilian ; Haimberger, Leopold ; Ishii, Masayoshi ; Johnson, Gregory C. ; Killick, Rachel E. ; King, Brian A. ; Kirchengast, Gottfried ; Kolodziejczyk, Nicolas ; Lyman, John ; Marzeion, Ben ; Mayer, Michael ; Monier, Maeva ; Monselesan, Didier Paolo ; Purkey, Sarah G. ; Roemmich, Dean ; Schweiger, Axel ; Seneviratne, Sonia I. ; Shepherd, Andrew ; Slater, Donald A. ; Steiner, Andrea K. ; Straneo, Fiammetta ; Timmermans, Mary-Louise ; Wijffels, Susan E.
    Human-induced atmospheric composition changes cause a radiative imbalance at the top of the atmosphere which is driving global warming. This Earth energy imbalance (EEI) is the most critical number defining the prospects for continued global warming and climate change. Understanding the heat gain of the Earth system – and particularly how much and where the heat is distributed – is fundamental to understanding how this affects warming ocean, atmosphere and land; rising surface temperature; sea level; and loss of grounded and floating ice, which are fundamental concerns for society. This study is a Global Climate Observing System (GCOS) concerted international effort to update the Earth heat inventory and presents an updated assessment of ocean warming estimates as well as new and updated estimates of heat gain in the atmosphere, cryosphere and land over the period 1960–2018. The study obtains a consistent long-term Earth system heat gain over the period 1971–2018, with a total heat gain of 358±37 ZJ, which is equivalent to a global heating rate of 0.47±0.1 W m−2. Over the period 1971–2018 (2010–2018), the majority of heat gain is reported for the global ocean with 89 % (90 %), with 52 % for both periods in the upper 700 m depth, 28 % (30 %) for the 700–2000 m depth layer and 9 % (8 %) below 2000 m depth. Heat gain over land amounts to 6 % (5 %) over these periods, 4 % (3 %) is available for the melting of grounded and floating ice, and 1 % (2 %) is available for atmospheric warming. Our results also show that EEI is not only continuing, but also increasing: the EEI amounts to 0.87±0.12 W m−2 during 2010–2018. Stabilization of climate, the goal of the universally agreed United Nations Framework Convention on Climate Change (UNFCCC) in 1992 and the Paris Agreement in 2015, requires that EEI be reduced to approximately zero to achieve Earth's system quasi-equilibrium. The amount of CO2 in the atmosphere would need to be reduced from 410 to 353 ppm to increase heat radiation to space by 0.87 W m−2, bringing Earth back towards energy balance. This simple number, EEI, is the most fundamental metric that the scientific community and public must be aware of as the measure of how well the world is doing in the task of bringing climate change under control, and we call for an implementation of the EEI into the global stocktake based on best available science. Continued quantification and reduced uncertainties in the Earth heat inventory can be best achieved through the maintenance of the current global climate observing system, its extension into areas of gaps in the sampling, and the establishment of an international framework for concerted multidisciplinary research of the Earth heat inventory as presented in this study. This Earth heat inventory is published at the German Climate Computing Centre (DKRZ, https://www.dkrz.de/, last access: 7 August 2020) under the DOI https://doi.org/10.26050/WDCC/GCOS_EHI_EXP_v2 (von Schuckmann et al., 2020).
  • Article
    The Argo Program : present and future
    (Oceanography Society, 2017-06) Jayne, Steven R. ; Roemmich, Dean ; Zilberman, Nathalie ; Riser, Stephen C. ; Johnson, Kenneth S. ; Johnson, Gregory C. ; Piotrowicz, Stephen R.
    The Argo Program has revolutionized large-scale physical oceanography through its contributions to basic research, national and international climate assessment, education, and ocean state estimation and forecasting. This article discusses the present status of Argo and enhancements that are underway. Extensions of the array into seasonally ice-covered regions and marginal seas as well as increased numbers of floats along the equator and around western boundary current extensions have been proposed. In addition, conventional Argo floats, with their 2,000 m sampling limit, currently observe only the upper half of the open ocean volume. Recent advances in profiling float technology and in the accuracy and stability of float-mounted conductivity-temperature-depth sensors make it practical to obtain measurements to 6,000 m. The Deep Argo array will help observe and constrain the global budgets of heat content, freshwater, and steric sea level, as well as the full-depth ocean circulation. Finally, another extension to the Argo Program is the addition of a diverse set of chemical sensors to profiling floats in order to build a Biogeochemical-Argo array to understand the carbon cycle, the biological pump, and ocean acidification.