Tropical Atlantic Observing System Review

Tropical Atlantic Observing System Review

Download the TAOS Review Report (

1. Rationale and motivation for the TAOS Review

The tropical Atlantic observing system was last reviewed in 2006 by CLIVAR (Climate and Ocean: Variability, Predictability and Change) and GCOS-GOOS-WCRP through the OOPC (Ocean Observations Panel for Climate), with a primary focus on PIRATA (Prediction and Research Moored Array in the Tropical Atlantic). Since then, the CLIVAR Tropical Atlantic Climate Experiment (TACE) and the EU program Enhancing Prediction of Tropical Atlantic Climate and its Impacts (PREFACE) have been completed. Scientific priorities and observational technologies have evolved since 2006 and in parallel the observing system has evolved. For example, Argo is now fully developed and has been operating successfully for more than ten years. PIRATA has also expanded to new sites and has enhanced its measurement suite with higher vertical resolution in the mixed layer, and new CO2 and O2 measurements. It is therefore timely to systematically review the requirements for sustained observations in the tropical Atlantic, to critically review the design of the sustained observing system in order to take advantage of what has been learned to date, to collectively identify new opportunities to build on past accomplishments, and to explore the possibility for expanded interdisciplinary initiatives with other communities, e.g. in biogeochemistry.

The Tropical Atlantic Observing System (TAOS) review was organised by the CLIVAR Atlantic Region Panel (ARP) and in close cooperation with the PIRATA consortium. CLIVAR ARP took the lead and coordinate the review, evaluated scientific progress since the last review, and recommended actions to advance sustained observing efforts in the tropical Atlantic. ARP sought OOPC’s endorsement for the review, and tried to involve the International Ocean Carbon Coordination Project (IOCCP) and/or the Integrated Marine Biosphere Research Program (IMBeR) and Surface Ocean - Lower Atmosphere Study (SOLAS), among others, as key partners as well. The review complemented other reviews focusing on different elements of the Atlantic observing system that took place in the next several years (for example, RAPID-AMOC and OSNAP). It benefits from parallel efforts being carried out in the Pacific and Indian Oceans, namely the Tropical Pacific Observing System TPOS 2020 project, and the Indian Ocean Observing System (IndOOS) review.  Results of the TAOS review could also feed into the AtlantOS design strategy that is currently being formulated in advance of the OceanObs’19 conference.

The review is forward looking and strategic, and focuses on possible changes to the observing system in the next decade. It considers new observing technologies, observing system requirements from the user community (e.g. weather and climate forecast), and observational products that to be delivered. The review is guided by the framework for ocean observing and make recommendations toward an adequate governing mechanism.  The review is comprehensive across all relevant observing system networks, including satellite observations, but with the focus primarily on the in situ observing system, and will consider atmospheric parameters (e.g., winds, surface fluxes) as well as aerosols, biogeochemistry and biology within the framework of a single integrated observing system. 


2. Terms of Reference

  1. Review and articulate the existing and anticipated future drivers for the Tropical Atlantic Observing System, encompassing research, operational, and societal applications. Key applications to be considered include: research on tropical Atlantic circulation and variability, coupled atmosphere-ocean variability and change, climate monitoring, modelling and forecasting (climate, ocean, seasonal to decadal and weather prediction), biogeochemistry, and fisheries.
  2. Evaluate (review/assess/prioritize) existing and potential requirements for sustained observations of essential ocean variables (EOVs) in the tropical Atlantic Ocean (extending from 25°N to 25°S) - in connection with TPOS2020 and IndOOS - and update them to reflect new knowledge and identified needs for scientific and societal applications.
  3. Evaluate the adequacy of existing observing strategies to deliver requirements for variables, and characterize their impacts. Characterize how in situ (e.g., PIRATA, Argo, drifters, and other data) and remote sensing observing systems are contributing to meet these scientific and functional requirements, and identify gaps, inefficiencies, and vulnerabilities.
  4. Provide recommendations on the current suite and configuration of observing systems to enhance their resilience and robustness in order to produce data in the most cost-efficient and sustainable manner within the anticipated envelope of capability and resources.
  5. Identify potential enhancement or reconfiguration of the sustained observing system suite to address gaps and new requirements.
  6. Evaluate requirements for delivery of data, and derived products and information, in real time and delayed mode (e.g., availability, quality, latency, integration/interoperability); evaluate the existing data systems for fitness for purpose.
  7. Assess readiness of new technologies, their potential impact and feasibility in addressing requirements, and their potential to contribute towards addressing gaps, improving robustness/resilience, and/or lowering costs per observation in the tropical Atlantic Ocean region; recommend new technologies with greatest potential to meet critical requirements and suggest approaches to improve the readiness for inclusion in the sustained observing system.
  8. Highlight the impacts of the tropical Atlantic observing system on the delivery of information/services of societal importance and relevance. Develop a report of the first TAOS Workshop, with recommendations on the development of a process for the ongoing evaluation of the observing system.


3. Outcomes (deliverables):

  • Final Report: Johns, William, S. Speich, M. Araujo and lead authors, (2021) Tropical Atlantic Observing System (TAOS) Review Report. CLIVAR-01/2021, 218 pp.
  • Community white paper at OceanObs'19: Foltz GR, Brandt P, Richter I, Rodríguez-Fonseca B, Hernandez F, Dengler M, Rodrigues RR, Schmidt JO, Yu L, Lefevre N, Da Cunha LC, McPhaden MJ, Araujo M, Karstensen J, Hahn J, Martín-Rey M, Patricola CM, Poli P, Zuidema P, Hummels R, Perez RC, Hatje V, Lübbecke JF, Polo I, Lumpkin R, Bourlès B, Asuquo FE, Lehodey P, Conchon A, Chang P, Dandin P, Schmid C, Sutton A, Giordani H, Xue Y, Illig S, Losada T, Grodsky SA, Gasparin F, Lee T, Mohino E, Nobre P, Wanninkhof R, Keenlyside N, Garcon V, Sánchez-Gómez E, Nnamchi HC, Drévillon M, Storto A, Remy E, Lazar A, Speich S, Goes M, Dorrington T, Johns WE, Moum JN, Robinson C, Perruche C, de Souza RB, Gaye AT, López-Parages J, Monerie P-A, Castellanos P, Benson NU, Hounkonnou MN, Duhá JT, Laxenaire R and Reul N (2019) The Tropical Atlantic Observing System. Front. Mar. Sci. 6:206. doi: 10.3389/fmars.2019.00206
  • Articles to highlight the major outcome of the review could be prepared for Eos, Bulletin of the American Meteorological Society, CLIVAR Exchanges, and/or US CLIVAR Variations, etc. (under preparation)


4. Timelines

Feb. 2018 Kick-off workshop, Terms of Reference and TAOS Review Committee formulated
Mar. - Sep. 2018 1st draft of scientific and societal drivers for TAOS
Oct. 2018 2nd TAOS Review Workshop and outline of the TAOS Review Report
Nov. 2018 - May 2019
  • 2nd draft of the scientific and societal drivers for TAOS
  • EOVs and ECVs
  • Societal relevance for each phenomena or processes
 May 2019 Community White Paper on TAOS published on Frontiers in Marine Science for the OceanObs'19,
Jun 2019 - Feb 2020
  • 1st draft of the TAOS Review Report
  • The combined list of EOVs and ECVs
Mar. 2020 Solicit comments from TAOS Review Committee for the 1st draft of TAOS Review Report
Apr. - Jun. 2020 Executive Summary and 2nd draft of the TAOS Review Report prepared
Jul. - Aug. 2020 Solicit comments from writing team, ARP, PIRATA, OOPC and broader community of experts and stakeholders on the 2nd draft of the TAOS Review Report.
May 2021 TAOS Review Report published online.


5. Review Committee

Name Affiliation Country
William Johns (Chair) RSMAS/MPO, University of Miami USA
Sabrina Speich Laboratoire of Météorologie Dynamique, IPSL  France
Jeff Knight Met Office UK
Moacyr Araujo Universidade Federal de Pernambuco Brazil
Katherine Hill GCOS-GOOS Scientific Officer, WMO Switzerland
Martin Visbeck GEOMAR Germany
Toste Tanhua GEOMAR Germany
Carol Robinson University of East Anglia UK
Neville Smith Private Consultant Australia
Yochanan Kushnir Lamont Doherty Earth Observatory (LDEO) USA
Magdalena Balmaseda European Center For Medium Range Weather Forecasts, Predictability Section, Research Department UK
Scott Stripling NOAA - US National Hurricane Center USA
Abderrahim Bentamy Institut Francais de Recherche Pour l'Exploitation de la Mer (Ifremer) France
Ping Chang Texas A&M University USA
Philippe Dandin Météo France France
Noel Keenlyside University of Bergen Norway


6. Lead and contributing authors

Lead Authors: 

William Johns, Sabrina Speich, Moacyr Araujo, Magdalena Balmaseda, Ping Chang, Philippe Dandin, Katherine Hill, Noel Keenlyside, Jeff Knight, Yochanan Kushnir, Mike McPhaden, Ingo Richter, Carol Robinson, Regina R. Rodrigues, Jörn O. Schmidt, Adrian Simmons, Neville Smith, Scott Stripling, Toste Tanhua, Martin Visbeck

List of Contributing Authors

Akintomide Afolayan Akinsanola, Abderrahim Bentamy, Bernard Bourlès, Peter Brandt, Patrice Brehmer, Marcus Dengler, Marie Drevillon, Gregory Foltz,  Emilia S. Gomez, Fabio H. V. Hazin, Markus Jochum, Johannes Karstensen, Matthias Lankhorst, Tony Lee, Nathalie Lefevre, Teresa Losada, Joke Lübbecke, Marta Martín-Rey, Vito Melo, Elsa Mohino,  Brian Mudumbi, José H. Muelbert, Hyacinth Nnamchi, Paulo Nobre, Renellys Perez, Irene Polo, Walter Robinson, Belén Rodríguez-Fonseca, Mathieu Rouault, Uwe Send, Jacques Servain,Rik Wanninkhof   

Jing Li