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| Desbruyères, Damien; Mercier, Herle; Maze, Guillaume; Daniault, Nathalie. |
| The Atlantic Meridional Overturning Circulation (AMOC) impacts ocean and atmosphere temperatures on a wide range of temporal and spatial scales. Here we use observational datasets to validate model-based inferences on the usefulness of thermodynamics theory in reconstructing AMOC variability at low frequency, and further build on this reconstruction to provide prediction of the near-future (2019–2022) North Atlantic state. An easily observed surface quantity – the rate of warm to cold transformation of water masses at high latitudes – is found to lead the observed AMOC at 45∘ N by 5–6 years and to drive its 1993–2010 decline and its ongoing recovery, with suggestive prediction of extreme intensities for the early 2020s. We further demonstrate that AMOC... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00503/61443/65162.pdf |
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| Garry, F. K.; Mcdonagh, E. L.; Blaker, A. T.; Roberts, C. D.; Desbruyères, Damien; Frajka-williams, E.; King, B. A.. |
| We construct a novel framework to investigate the uncertainties and biases associated with estimates of deep ocean temperature change from hydrographic sections, and demonstrate this framework in an eddy‐permitting ocean model. Biases in estimates from observations arise due to sparse spatial coverage (few sections in a basin), low frequency of occupations (typically 5‐10 years apart), mismatches between the time period of interest and span of occupations, and from seasonal biases relating to the practicalities of sampling during certain times of year. Between the years 1990 and 2010, the modeled global abyssal ocean biases are small, although regionally some biases (expressed as a heat flux into the 4000 ‐ 6000 m layer) can be up to 0.05 W m−2. In this... |
| Tipo: Text |
Palavras-chave: Deep oceans; Temperature trends; Ocean heat content; Decadal variability; Ocean modeling; Observational uncertainties. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00479/59021/61642.pdf |
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| Desbruyères, Damien; Sinha, B.; Mcdonagh, E. L.; Josey, S. A.; Holliday, N. P.; Smeed, D. A.; New, A. L.; Megann, A.; Moat, B. I.. |
| The decadal to multi‐decadal temperature variability of the intermediate (700 – 2000 m) North Atlantic Subpolar Gyre (SPG) significantly imprints the global pattern of ocean heat uptake. Here, the origins and dominant pathways of this variability are investigated with an ocean analysis product (EN4), an ocean state estimate (ECCOv4), and idealized modeling approaches. Sustained increases and decreases of intermediate temperature in the SPG correlate with long‐lasting warm and cold states of the upper ocean with the largest anomalous vertical heat exchanges confined to the vicinity of continental boundaries and strong ocean currents. In particular, vertical diffusive processes along the boundaries of the Labrador, Irminger, and Newfoundland basins are... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00636/74853/75239.pdf |
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| Von Schuckmann, Karina; Cheng, Lijing; Palmer, Matthew D.; Hansen, James; Tassone, Caterina; Aich, Valentin; Adusumilli, Susheel; Beltrami, Hugo; Boyer, Tim; Cuesta-valero, Francisco José; Desbruyères, Damien; Domingues, Catia; García-garcía, Almudena; Gentine, Pierre; Gilson, John; Gorfer, Maximilian; Haimberger, Leopold; Ishii, Masayoshi; Johnson, Gregory C.; Killick, Rachel; King, Brian A.; Kirchengast, Gottfried; Kolodziejczyk, Nicolas; Lyman, John; Marzeion, Ben; Mayer, Michael; Monier, Maeva; Monselesan, Didier Paolo; Purkey, Sarah; 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... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00648/76036/76956.pdf |
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| Desbruyères, Damien; Chafik, Léon; Maze, Guillaume. |
| The Subpolar North Atlantic is known for rapid reversals of decadal temperature trends, with ramifications encompassing the large-scale meridional overturning and gyre circulations, Arctic heat and mass balances, or extreme continental weather. Here, we combine datasets derived from sustained ocean observing systems (satellite and in situ), idealized observation-based modelling (advection-diffusion of a passive tracer), and a machine learning technique (ocean profile clustering) to document and explain the most-recent and ongoing cooling-to-warming transition of the Subpolar North Atlantic. Following a gradual cooling of the region that was persisting since 2006, a surface-intensified and large-scale warming sharply emerged in 2016 following an ocean... |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00682/79432/82033.pdf |
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| Moat, Ben I.; Smeed, David A.; Frajka-williams, Eleanor; Desbruyères, Damien; Beaulieu, Claudie; Johns, William E.; Rayner, Darren; Sanchez-franks, Alejandra; Baringer, Molly O.; Volkov, Denis; Jackson, Laura C.; Bryden, Harry L.. |
| The strength of the Atlantic meridional overturning circulation (AMOC) at 26∘ N has now been continuously measured by the RAPID array over the period April 2004–September 2018. This record provides unique insight into the variability of the large-scale ocean circulation, previously only measured by sporadic snapshots of basin-wide transport from hydrographic sections. The continuous measurements have unveiled striking variability on timescales of days to a decade, driven largely by wind forcing, contrasting with previous expectations about a slowly varying buoyancy-forced large-scale ocean circulation. However, these measurements were primarily observed during a warm state of the Atlantic multidecadal variability (AMV) which has been steadily declining... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00643/75537/76443.pdf |
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| Liu, Chunlei; Allan, Richard P.; Mayer, Michael; Hyder, Patrick; Desbruyères, Damien; Cheng, Lijing; Xu, Jianjun; Xu, Feng; Zhang, Yu. |
| The study of energy flows in the Earth system is essential for understanding current climate change. To understand how energy is accumulating and being distributed within the climate system, an updated reconstruction of energy fluxes at the top of atmosphere, surface and within the atmosphere derived from observations is presented. New satellite and ocean data are combined with an improved methodology to quantify recent variability in meridional and ocean to land heat transports since 1985. A global top of atmosphere net imbalance is found to increase from 0.10 ± 0.61 W m−2 over 1985–1999 to 0.62 ± 0.1 W m−2 over 2000–2016, and the uncertainty of ± 0.61 W m−2 is related to the Argo ocean heat content changes (± 0.1 W m−2) and an additional uncertainty... |
| Tipo: Text |
Palavras-chave: TOA flux; Net surface flux; Energy transport. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00652/76383/77393.pdf |
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| Beal, L. M.; Vialard, J.; Roxy, M.k.; Li, J.; Andres, M.; Annamalai, H.; Feng, M.; Han, W.; Hood, R.; Lee, T.; Lengaigne, Matthieu; Lumpkin, R.; Masumoto, Y.; Mcphaden, M.j.; Ravichandran, M.; Shinoda, T.; Sloyan, B.m.; Strutton, P.g.; Subramanian, A.c.; Tozuka, T.; Ummenhofer, C.c.; Unnikrishnan, A.s.; Wiggert, J.; Yu, L.; Cheng, L.; Desbruyères, Damien; Parvathi, V. |
| The Indian Ocean Observing System (IndOOS), established in 2006, is a multi-national network of sustained oceanic measurements that underpin understanding and forecasting of weather and climate for the Indian Ocean region and beyond. Almost one-third of humanity indeed lives around the Indian Ocean, many in countries dependent on fisheries and rain-fed agriculture that are vulnerable to climate variability and extremes. The Indian Ocean alone has absorbed a quarter of the global oceanic heat uptake over the last two decades and the fate of this heat and its impact on future change is unknown. Climate models project accelerating sea level rise, more frequent extremes in monsoon rainfall, and decreasing oceanic productivity. In view of these new scientific... |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00644/75658/76530.pdf |
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