scholarly journals The Present and Future System for Measuring the Atlantic Meridional Overturning Circulation and Heat Transport

2010 ◽  
Author(s):  
Stuart Cunningham ◽  
Stuart Cunningham ◽  
Stuart Cunningham ◽  
Stuart Cunningham ◽  
Stuart Cunningham ◽  
...  
Keyword(s):  
Heat Transport ◽  
Atlantic Meridional Overturning Circulation ◽  
Meridional Overturning Circulation ◽  
Overturning Circulation ◽  
Future System ◽  
Meridional Overturning

scholarly journals Mid-pliocene Atlantic Meridional Overturning Circulation not unlike modern

2013 ◽  
Vol 9 (4) ◽  
pp. 1495-1504 ◽  
Author(s):  
Z.-S. Zhang ◽  
K. H. Nisancioglu ◽  
M. A. Chandler ◽  
A. M. Haywood ◽  
B. L. Otto-Bliesner ◽  
...  
Keyword(s):  
Heat Transport ◽  
Climate Models ◽  
Atlantic Meridional Overturning Circulation ◽  
Meridional Overturning Circulation ◽  
Ocean Heat Transport ◽  
Overturning Circulation ◽  
Consistent Change ◽  
Intercomparison Project ◽  
Meridional Overturning ◽  
Consistent Increase

Abstract. In the Pliocene Model Intercomparison Project (PlioMIP), eight state-of-the-art coupled climate models have simulated the mid-Pliocene warm period (mPWP, 3.264 to 3.025 Ma). Here, we compare the Atlantic Meridional Overturning Circulation (AMOC), northward ocean heat transport and ocean stratification simulated with these models. None of the models participating in PlioMIP simulates a strong mid-Pliocene AMOC as suggested by earlier proxy studies. Rather, there is no consistent increase in AMOC maximum among the PlioMIP models. The only consistent change in AMOC is a shoaling of the overturning cell in the Atlantic, and a reduced influence of North Atlantic Deep Water (NADW) at depth in the basin. Furthermore, the simulated mid-Pliocene Atlantic northward heat transport is similar to the pre-industrial. These simulations demonstrate that the reconstructed high-latitude mid-Pliocene warming can not be explained as a direct response to an intensification of AMOC and concomitant increase in northward ocean heat transport by the Atlantic.

scholarly journals Mid-pliocene Atlantic meridional overturning circulation not unlike modern?

2013 ◽  
Vol 9 (2) ◽  
pp. 1297-1319 ◽  
Author(s):  
Z.-S. Zhang ◽  
K. H. Nisancioglu ◽  
M. A. Chandler ◽  
A. M. Haywood ◽  
B. L. Otto-Bliesner ◽  
...  
Keyword(s):  
Heat Transport ◽  
Climate Models ◽  
Atlantic Meridional Overturning Circulation ◽  
Meridional Overturning Circulation ◽  
Ocean Heat Transport ◽  
Overturning Circulation ◽  
Consistent Change ◽  
Intercomparison Project ◽  
Meridional Overturning ◽  
Consistent Increase

Abstract. In the Pliocene Model Intercomparison Project (PlioMIP), eight state-of-the-art coupled climate models have simulated the mid-Pliocene warm period (mPWP, 3.264 to 3.025 Ma). Here, we compare the Atlantic Meridional Overturning Circulation (AMOC), northward ocean heat transport and ocean stratification simulated with these models. None of the models participating in the PlioMIP simulates a strong mid-Pliocene AMOC as suggested by earlier proxy studies. Rather, there is no consistent increase in AMOC maximum among the PlioMIP models. The only consistent change in AMOC is a shoaling of the overturning cell in the Atlantic, and a reduced influence of North Atlantic Deep Water (NADW) at depth in the basin. Furthermore, the simulated mid-Pliocene Atlantic northward heat transport is similar to the pre-industrial. These simulations demonstrate that the reconstructed high latitude mid-Pliocene warming can not be explained as a direct response to an intensification of AMOC and concomitant increase in northward ocean heat transport by the Atlantic.

Sensitivity of the Atlantic Meridional Overturning Circulation to Model Resolution in CMIP6 HighResMIP Simulations

2020 ◽  
Author(s):  
Dorotea Iovino ◽  
Malcolm J. Roberts ◽  
Laura C. Jackson ◽  
Christopher D. Roberts ◽  
Virna Meccia ◽  
...  
Keyword(s):  
Heat Transport ◽  
Ocean Circulation ◽  
Atlantic Meridional Overturning Circulation ◽  
Meridional Overturning Circulation ◽  
The Arctic ◽  
Climate Modelling ◽  
Florida Current ◽  
Model Resolution ◽  
Overturning Circulation ◽  
Meridional Overturning

<p>The Atlantic Meridional Overturning Circulation (AMOC) is a key component of the three-dimensional ocean circulation that transports warm and salty water northward, and exports cold and dense water from the Arctic southward.</p><p>The simulated AMOC in Coupled Model Intercomparison Project models (both coupled and ocean-only) has been studied extensively. However, correctly simulating the AMOC with these models remains a challenge for the climate modelling community. One model aspect that can affect the AMOC representation is the model resolution (i.e. grid spacing).</p><p>Here, we examine key aspects of the North Atlantic Ocean circulation using a multi-model, multi-resolution ensemble based on the CMIP6 HighResMIP coupled experiments. The AMOC and associated heat transport tend to become stronger as model resolution increases, particularly when the ocean resolution changes from non-eddying to eddy-present and eddy-rich. However, the circulation remains too shallow compared to observations for most models, and this, together with temperature biases, cause the northward heat transport to be too low for a given overturning strength.</p><p>In the period 2015-2050, the overturning circulation tends to decline more rapidly in the higher resolution models by more than 20% compared to the control state, which is related to both themean state and to the subpolar gyre contribution to deep water formation. The main part of the decline comes from the Florida Current component of the circulation.</p>

scholarly journals Influence of the Atlantic meridional overturning circulation on the U.S. extreme cold weather

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Jianjun Yin ◽  
Ming Zhao
Keyword(s):  
Heat Exchange ◽  
Heat Transport ◽  
Atlantic Meridional Overturning Circulation ◽  
Meridional Overturning Circulation ◽  
Cold Weather ◽  
Overturning Circulation ◽  
Meridional Overturning ◽  
Extreme Cold ◽  
The U.S ◽  
Hosing Experiment

AbstractDue to its large northward heat transport, the Atlantic meridional overturning circulation influences both weather and climate at the mid-latitude Northern Hemisphere. Here we use a state-of-the-art global weather/climate modeling system with high resolution (GFDL CM4C192) to quantify this influence focusing on the U.S. extreme cold weather during winter. We perform a control simulation and the water-hosing experiment to obtain two climate states with and without a vigorous Atlantic meridional overturning circulation. We find that in the control simulation with an overturning circulation, the U.S. east of the Rockies is a region characterized by intense north-south heat exchange in the atmosphere during winter. Without the northward heat transport by the overturning circulation in the hosing experiment, this channel of atmospheric heat exchange becomes even more active through the Bjerknes compensation mechanism. Over the U.S., extreme cold weather intensifies disproportionately compared with the mean climate response after the shutdown of the overturning circulation. Our results suggest that an active overturning circulation in the present-day climate likely makes the U.S. winter less harsh and extreme.

scholarly journals Suppression of Atlantic Meridional Overturning Circulation Variability at Increased CO2

2016 ◽  
Vol 29 (11) ◽  
pp. 4155-4164 ◽  
Author(s):  
Douglas G. MacMartin ◽  
Laure Zanna ◽  
Eli Tziperman
Keyword(s):  
Heat Transport ◽  
General Circulation ◽  
Function Analysis ◽  
Atlantic Meridional Overturning Circulation ◽  
Meridional Overturning Circulation ◽  
Ocean Dynamics ◽  
Future Climate Change ◽  
Overturning Circulation ◽  
Transfer Function Analysis ◽  
Meridional Overturning

Abstract Multidecadal variability in the Atlantic meridional overturning circulation (AMOC) is shown to differ significantly between the 4 × CO2 and preindustrial control simulations of the GFDL Earth System Model, version 2M (ESM2M) general circulation model (GCM). In the preindustrial simulation, this model has a peak in the power spectrum of both AMOC and northward heat transport at latitudes between 26° and 50°N. In the 4 × CO2 simulation, the only significant spectral peak is near 60°N. Understanding these differences is important for understanding the effect of future climate change on climate variability, as well as for providing insight into the physics underlying AMOC variability. Transfer function analysis demonstrates that the shift is predominantly due to a shift in the internal ocean dynamics rather than a change in stochastic atmospheric forcing. Specifically, the reduction in variance from 26° to 45°N is due to an increased stratification east of Newfoundland that results from the shallower and weaker mean overturning. The reduced AMOC variance that accompanies the reduced mean value of the AMOC at 4 × CO2 differs from predictions of simple box models that predict a weaker circulation to be closer to a stability bifurcation point and, therefore, be accompanied by amplified variability. The high-latitude variability in the 4 × CO2 simulation is related to the advection of anomalies by the subpolar gyre, distinct from the variability mechanism in the control simulation at lower latitudes. The 4 × CO2 variability has only a small effect on midlatitude meridional heat transport, but does significantly affect sea ice in the northern North Atlantic.

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