Observing the Atlantic Meridional Overturning Circulation yields a decade of inevitable surprises

Srokosz, Meric; Bryden, Harry L.

doi:10.1126/science.1255575

Cited by 205 publications

(169 citation statements)

References 79 publications

(76 reference statements)

Supporting

Mentioning

164

Contrasting

Order By: Relevance

“…12. Power spectra from the HiGEM control simulation and the RAPID observations (Srokosz and Bryden 2015) are included for comparison. All the power spectra display a prominent annual cycle, but the variabilities on time scales of 1-5 yr differ markedly.…”

Section: Atlantic Meridional Overturning Circulationmentioning

confidence: 99%

Improved Climate Simulations through a Stochastic Parameterization of Ocean Eddies

et al. 2016

View full text Add to dashboard Cite

In climate simulations, the impacts of the subgrid scales on the resolved scales are conventionally represented using deterministic closure schemes, which assume that the impacts are uniquely determined by the resolved scales. Stochastic parameterization relaxes this assumption, by sampling the subgrid variability in a computationally inexpensive manner. This study shows that the simulated climatological state of the ocean is improved in many respects by implementing a simple stochastic parameterization of ocean eddies into a coupled atmosphere-ocean general circulation model. Simulations from a highresolution, eddy-permitting ocean model are used to calculate the eddy statistics needed to inject realistic stochastic noise into a low-resolution, non-eddy-permitting version of the same model. A suite of four stochastic experiments is then run to test the sensitivity of the simulated climate to the noise definition by varying the noise amplitude and decorrelation time within reasonable limits. The addition of zero-mean noise to the ocean temperature tendency is found to have a nonzero effect on the mean climate. Specifically, in terms of the ocean temperature and salinity fields both at the surface and at depth, the noise reduces many of the biases in the low-resolution model and causes it to more closely resemble the highresolution model. The variability of the strength of the global ocean thermohaline circulation is also improved. It is concluded that stochastic ocean perturbations can yield reductions in climate model error that are comparable to those obtained by refining the resolution, but without the increased computational cost. Therefore, stochastic parameterizations of ocean eddies have the potential to significantly improve climate simulations.

show abstract

Section: Atlantic Meridional Overturning Circulationmentioning

confidence: 99%

Improved Climate Simulations through a Stochastic Parameterization of Ocean Eddies

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The MOC system dominates the north-south transport of heat and salt in the Atlantic Ocean (e.g., Trenberth et al, 2001;Ganachaud and Wunsch, 2003;Johns et al, 2011), and studies using numerical climate models suggest significant connections between variations in the MOC and changes in societally relevant quantities such as continental precipitation patterns, hurricane intensification, and regional sea level (e.g., Vellinga and Wood, 2002;Stouffer et al, 2006;Latif et al, 2007;McCarthy et al, 2015;Lopez et al, 2016). The pathways that the DWBC, and the lower limb of the MOC, take as they pass through the South Atlantic are not as well underPublished by Copernicus Publications on behalf of the European Geosciences Union.…”

Section: Introductionmentioning

confidence: 99%

Characteristics and causes of Deep Western Boundary Current transport variability at 34.5° S during 2009–2014

et al. 2017

View full text Add to dashboard Cite

Abstract. The Deep Western Boundary Current (DWBC) at 34.5 • S in the South Atlantic carries a significant fraction of the cold deep limb of the Meridional Overturning Circulation (MOC), and therefore its variability affects the meridional heat transport and consequently the regional and global climate. Nearly 6 years of observations from a line of pressure-equipped inverted echo sounders (PIESs) have yielded an unprecedented data set for studying the characteristics of the time-varying DWBC volume transport at 34.5 • S. Furthermore, the horizontal resolution of the observing array was greatly improved in December 2012 with the addition of two current-and-pressure-equipped inverted echo sounders (CPIESs) at the midpoints of the two westernmost pairs of PIES moorings. Regular hydrographic sections along the PIES/CPIES line confirm the presence of recently ventilated North Atlantic Deep Water carried by the DWBC. The time-mean absolute geostrophic transport integrated within the DWBC layer, defined between 800-4800 dbar and within longitude bounds of 51.5 to 44.5 • W, is −15 Sv (1 Sv = 10 6 m 3 s −1 ; negative indicates southward flow). The observed peak-to-peak range in volume transport using these integration limits is from −89 to +50 Sv, and the temporal standard deviation is 23 Sv. Testing different vertical integration limits based on time-mean water-mass property levels yields small changes to these values, but no significant alteration to the character of the transport time series. The time-mean southward DWBC flow at this latitude is confined west of 49.5 • W, with recirculations dominating the flow further offshore. As with other latitudes where the DWBC has been observed for multiple years, the time variability greatly exceeds the time mean, suggesting the presence of strong coherent vortices and/or Rossby Wave-like signals propagating to the boundary from the interior.

show abstract

“…Knight et al [32] has simulated the thermohaline circulation in the North Atlantic over the past 1400 years and predicts the waxing and waning of the surface circulation over the past centuries. While, deep Atlantic current measurements have so far not established a connection with North Atlantic deep-water formation and the NAO or AMO [38], the RAPID current array at 26.5°N over the period of 2004 to 2012 has indicated a decline of ~0.5 Sv· y −1 in the AMOC which exceeds the rate of decline due to climate warming of ~0.05 Sv· y −1 and may be due to decadal change [39].…”

Section: Causes For the Global Oscillationmentioning

confidence: 99%

Decadal Patterns of Westerly Winds, Temperatures, Ocean Gyre Circulations and Fish Abundance: A Review

Oviatt

Smith

McManus

et al. 2015

Climate

View full text Add to dashboard Cite

Abstract:The purpose of this review is to describe the global scope of the multidecadal climate oscillations that go back at least, through several hundred years. Literature, historic data, satellite data and global circulation model output have been used to provide evidence for the zonal and meridional jet stream patterns. These patterns were predominantly zonal from the 1970s to 1990s and switched since the 1990s to a meridional wind phase, with weakening jet streams forming Rossby waves in the northern and southern hemispheres. A weakened northern jet stream has allowed northerly winds to flow down over the continents in the northern hemisphere during the winter period, causing some harsh winters and slowing anthropogenic climate warming regionally. Wind oscillations impact ocean gyre circulation affecting upwelling strength and pelagic fish abundance with synchronous behavior in sub Arctic gyres during phases of the oscillation and asynchronous behavior in subtropical gyres between the Atlantic and Pacific oceans.

show abstract

Observing the Atlantic Meridional Overturning Circulation yields a decade of inevitable surprises

Cited by 205 publications

References 79 publications

Improved Climate Simulations through a Stochastic Parameterization of Ocean Eddies

Improved Climate Simulations through a Stochastic Parameterization of Ocean Eddies

Characteristics and causes of Deep Western Boundary Current transport variability at 34.5° S during 2009–2014

Decadal Patterns of Westerly Winds, Temperatures, Ocean Gyre Circulations and Fish Abundance: A Review

Contact Info

Product

Resources

About

Observing the Atlantic Meridional Overturning Circulation yields a decade of inevitable surprises

Cited by 205 publications

References 79 publications

Improved Climate Simulations through a Stochastic Parameterization of Ocean Eddies

Improved Climate Simulations through a Stochastic Parameterization of Ocean Eddies

Characteristics and causes of Deep Western Boundary Current transport variability at 34.5° S during 2009–2014

Decadal Patterns of Westerly Winds, Temperatures, Ocean Gyre Circulations and Fish Abundance: A Review

Contact Info

Product

Resources

About

Characteristics and causes of Deep Western Boundary Current transport variability at 34.5° S during 2009–2014