Structure and Variability of the Antilles Current at 26.5°N

Meinen, Christopher S.; Johns, William E.; Moat, Ben; Smith, Ryan Hunter; Johns, Elizabeth; Rayner, Darren; Frajka‐Williams, Eleanor; García, Rigoberto F.; Garzoli, Silvia L.

doi:10.1029/2018jc014836

Cited by 23 publications

(31 citation statements)

References 48 publications

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“…The Florida‐Bahamas Strait transport is larger by over 50% in models; however due to the low resolution, the Bahamas archipelago is not resolved so that the modeled western boundary transport also includes the Antilles Current East of the Bahamas. Adding the measured 4.7 ± 7.5 Sv Antilles Current transport (Meinen et al, ) gives a reasonable modeled behavior, with a positive bias though. Lastly, the Indonesian throughflow transport is well represented by both models.…”

Section: Resultsmentioning

confidence: 76%

Evaluation of CNRM Earth System Model, CNRM‐ESM2‐1: Role of Earth System Processes in Present‐Day and Future Climate

Séférian

Nabat

Michou

et al. 2019

J Adv Model Earth Syst

461

167

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This study introduces CNRM-ESM2-1, the Earth system (ES) model of second generation developed by CNRM-CERFACS for the sixth phase of the Coupled Model Intercomparison Project (CMIP6). CNRM-ESM2-1 offers a higher model complexity than the Atmosphere-Ocean General Circulation Model CNRM-CM6-1 by adding interactive ES components such as carbon cycle, aerosols, and atmospheric chemistry. As both models share the same code, physical parameterizations, and grid resolution, they offer a fully traceable framework to investigate how far the represented ES processes impact the model performance over present-day, response to external forcing and future climate projections. Using a large variety of CMIP6 experiments, we show that represented ES processes impact more prominently the model response to external forcing than the model performance over present-day. Both models display comparable performance at replicating modern observations although the mean climate of CNRM-ESM2-1 is slightly warmer than that of CNRM-CM6-1. This difference arises from land cover-aerosol interactions where the use of different soil vegetation distributions between both models impacts the rate of dust emissions. This interaction results in a smaller aerosol burden in CNRM-ESM2-1 than in CNRM-CM6-1, leading to a different surface radiative budget and climate. Greater differences are found when comparing the model response to external forcing and future climate projections. Represented ES processes damp future warming by up to 10% in CNRM-ESM2-1 with respect to CNRM-CM6-1. The representation of land vegetation and the CO 2 -water-stomatal feedback between both models explain about 60% of this difference. The remainder is driven by other ES feedbacks such as the natural aerosol feedback.

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Section: Resultsmentioning

confidence: 76%

Evaluation of CNRM Earth System Model, CNRM‐ESM2‐1: Role of Earth System Processes in Present‐Day and Future Climate

Séférian

Nabat

Michou

et al. 2019

J Adv Model Earth Syst

461

167

View full text Add to dashboard Cite

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“…However, one can put bounds on stochastic trends based on the time-series properties of the available data. Performing simulations of a random stationary process, with the same integral timescale and variance as the observed Antilles Current transport over 2005-2015 8 , I find that stochastic transport trends of ±2.9 and ±1.2 Sv century −1 are possible on 50-and 100-y timescales, respectively (Supplementary Note 3 and Supplementary Fig. 11).…”

Section: Resultsmentioning

confidence: 80%

“…The Antilles Current is a subsurface western boundary current constrained to the upper slope east of Abaco at 26.5°N. Data from the RAPID array since 2004 show that the Antilles Current has a mean northward transport of between 1 and 6 Sv 6 – 8 , 66 . While weaker in a time-average sense, the Antilles Current transport is as variable as, if not more variable than, the Florida Current transport 7 , 8 .…”

Section: Resultsmentioning

confidence: 99%

“…1). Together with the weaker Antilles Current [5][6][7][8] , the Florida Current forms the major western boundary current in the subtropical North Atlantic Ocean at 27°N , providing closure to the wind-driven interior gyre circulation [9][10][11] , and acting as a vital limb of the Atlantic meridional overturning circulation 12 . Due to its transport of heat and other tracers, the Florida Current has an important role in climate [13][14][15] .…”

mentioning

confidence: 99%

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Likely weakening of the Florida Current during the past century revealed by sea-level observations

Piecuch

2020

Nat Commun

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The Florida Current marks the beginning of the Gulf Stream at Florida Straits, and plays an important role in climate. Nearly continuous measurements of Florida Current transport are available at 27°N since 1982. These data are too short for assessing possible multidecadal or centennial trends. Here I reconstruct Florida Current transport during 1909-2018 using probabilistic methods and principles of ocean physics applied to the available transport data and longer coastal sea-level records. Florida Current transport likely declined steadily during the past century. Transport since 1982 has likely been weaker on average than during 1909-1981. The weakest decadal-mean transport in the last 110 y likely took place in the past two decades. Results corroborate hypotheses that the deep branch of the overturning circulation declined over the recent past, and support relationships observed in climate models between the overturning and surface western boundary current transports at multidecadal and longer timescales.

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“…At 26 • N, the transport variability is unlikely to be strongly different between the AMOC in depth space and density class as isopycnals across the broad expanse of the basin (6000 km) are nearly flat. However, in the subpolar gyre, the overturning is defined in density coordinates (Pickart and Spall, 2007;Mercier et al, 2015;Lozier et al, 2019) to better account for the dynamics of buoyancy redistribution in the ocean, which is also carried out by the horizontal gyre circulation. In the subpolar gyre, overturning is a measure of water-mass transformation between the northward "inflow" and southward "outflow", irrespective of the depth at which it occurs.…”

Section: Amoc Transport At 45 • Nmentioning

confidence: 99%

Pending recovery in the strength of the meridional overturning circulation at 26° N

et al. 2020

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Abstract. 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 since a peak in 2008–2010. In 2013–2015, a period of strong buoyancy forcing by the atmosphere drove intense water-mass transformation in the subpolar North Atlantic and provides a unique opportunity to investigate the response of the large-scale ocean circulation to buoyancy forcing. Modelling studies suggest that the AMOC in the subtropics responds to such events with an increase in overturning transport, after a lag of 3–9 years. At 45∘ N, observations suggest that the AMOC may already be increasing. Examining 26∘ N, we find that the AMOC is no longer weakening, though the recent transport is not above the long-term mean. Extending the record backwards in time at 26∘ N with ocean reanalysis from GloSea5, the transport fluctuations at 26∘ N are consistent with a 0- to 2-year lag from those at 45∘ N, albeit with lower magnitude. Given the short span of time and anticipated delays in the signal from the subpolar to subtropical gyres, it is not yet possible to determine whether the subtropical AMOC strength is recovering nor how the AMOC at 26∘ N responds to intense buoyancy forcing.

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Structure and Variability of the Antilles Current at 26.5°N

Cited by 23 publications

References 48 publications

Evaluation of CNRM Earth System Model, CNRM‐ESM2‐1: Role of Earth System Processes in Present‐Day and Future Climate

Evaluation of CNRM Earth System Model, CNRM‐ESM2‐1: Role of Earth System Processes in Present‐Day and Future Climate

Likely weakening of the Florida Current during the past century revealed by sea-level observations

Pending recovery in the strength of the meridional overturning circulation at 26° N

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