Sustainable observations of the AMOC: Methodology and Technology

• Published in: Reviews of Geophysics
• Main Authors: Mccarthy, G.D., Brown, P.J., Flagg, C.N., Goni, G., Houpert, L., Hughes, C.W., Hummels, R., Inall, M., Jochumsen, K., Larsen, K.M.H., Lherminier, Pascale, Meinen, C.S., Moat, B.I., Rayner, D., Rhein, M., Roessler, A., Schmid, C., Smeed, D.A.
• Other Authors: Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), European Project: 633211,H2020,H2020-BG-2014-2,AtlantOS(2015), European Project: 727852,Blue-Action(2016)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: [SDU]Sciences of the Universe [physics]; Arctic
• Online Access: https://hal.science/hal-04202468; https://hal.science/hal-04202468/document; https://hal.science/hal-04202468/file/Reviews%20of%20Geophysics%20-%202019%20-%20McCarthy%20-%20Sustainable%20Observations%20of%20the%20AMOC%20Methodology%20and%20Technology.pdf; https://doi.org/10.1029/2019RG000654

The Atlantic Meridional Overturning Circulation (AMOC) is a key mechanism of heat, freshwater, and carbon redistribution in the climate system. The precept that the AMOC has changed abruptly in the past, notably during and at the end of the last ice age, and that it is ‘very likely’ to weaken in the coming century due to anthropogenic climate change is a key motivation for sustained observations of the AMOC. This paper reviews the methodology and technology used to observe the AMOC and assesses these ideas and systems for accuracy, shortcomings, potential improvements and sustainability. We review hydrographic techniques and look at how these traditional techniques can meet modern requirements. Transport mooring arrays provide the ‘gold standard’ for sustained AMOC observing, utilizing dynamic height, current meter, and other instrumentation and techniques to produce continuous observations of the AMOC. We consider the principle of these systems and how they can be sustained and improved into the future. Techniques utilizing indirect measurements, such as satellite altimetry, coupled with in‐situ measurements, such as the Argo float array, are also discussed. Existing technologies that perhaps have not been fully exploited for estimating AMOC are reviewed and considered for this purpose. Technology is constantly evolving and we look to the future of technology and how it can be deployed for sustained and expanded AMOC measurements. Finally, all of these methodologies and technologies are considered with a view to a sustained and sustainable future for AMOC observation.Plain Language SummaryThe Atlantic Meridional Overturning Circulation (AMOC) is a system of ocean currents (sometimes known as the Gulf Stream System or the Great Ocean Conveyor Belt) that is important because of how it moves heat and carbon around the planet. Due to human‐induced climate change, the AMOC is predicted to weaken substantially, with adverse impacts for regions dependent on the supply of warmth from the AMOC, including northwest ...