Unstable behaviour of an upper ocean-atmosphere coupled model: role of atmospheric radiative processes and oceanic heat transport

1999 ◽  
Vol 15 (12) ◽  
pp. 895-908 ◽  
Author(s):  
E. Cohen-Solal ◽  
H. Le Treut
Keyword(s):  
Heat Transport ◽  
Coupled Model ◽  
Upper Ocean ◽  
Oceanic Heat Transport ◽  
Radiative Processes ◽  
Ocean Atmosphere

scholarly journals Response of the Atlantic Thermohaline Circulation to Increased Atmospheric CO2 in a Coupled Model

2004 ◽  
Vol 17 (21) ◽  
pp. 4267-4279 ◽  
Author(s):  
Aixue Hu ◽  
Gerald A. Meehl ◽  
Warren M. Washington ◽  
Aiguo Dai
Keyword(s):  
Sea Ice ◽  
Heat Transport ◽  
North Atlantic ◽  
Thermohaline Circulation ◽  
Climate Model ◽  
Coupled Model ◽  
The Arctic ◽  
Labrador Sea ◽  
Upper Ocean ◽  
Gin Seas

Abstract Changes in the thermohaline circulation (THC) due to increased CO2 are important in future climate regimes. Using a coupled climate model, the Parallel Climate Model (PCM), regional responses of the THC in the North Atlantic to increased CO2 and the underlying physical processes are studied here. The Atlantic THC shows a 20-yr cycle in the control run, qualitatively agreeing with other modeling results. Compared with the control run, the simulated maximum of the Atlantic THC weakens by about 5 Sv (1 Sv ≡ 106 m3 s−1) or 14% in an ensemble of transient experiments with a 1% CO2 increase per year at the time of CO2 doubling. The weakening of the THC is accompanied by reduced poleward heat transport in the midlatitude North Atlantic. Analyses show that oceanic deep convective activity strengthens significantly in the Greenland–Iceland–Norway (GIN) Seas owing to a saltier (denser) upper ocean, but weakens in the Labrador Sea due to a fresher (lighter) upper ocean and in the south of the Denmark Strait region (SDSR) because of surface warming. The saltiness of the GIN Seas are mainly caused by an increased salty North Atlantic inflow, and reduced sea ice volume fluxes from the Arctic into this region. The warmer SDSR is induced by a reduced heat loss to the atmosphere, and a reduced sea ice flux into this region, resulting in less heat being used to melt ice. Thus, sea ice–related salinity effects appear to be more important in the GIN Seas, but sea ice–melt-related thermal effects seem to be more important in the SDSR region. On the other hand, the fresher Labrador Sea is mainly attributed to increased precipitation. These regional changes produce the overall weakening of the THC in the Labrador Sea and SDSR, and more vigorous ocean overturning in the GIN Seas. The northward heat transport south of 60°N is reduced with increased CO2, but increased north of 60°N due to the increased flow of North Atlantic water across this latitude.

scholarly journals Response of ENSO and the Mean State of the Tropical Pacific to Extratropical Cooling and Warming: A Study Using the IAP Coupled Model

2009 ◽  
Vol 22 (22) ◽  
pp. 5902-5917 ◽  
Author(s):  
Y. Yu ◽  
D-Z. Sun
Keyword(s):  
Climate Change ◽  
Climate Modeling ◽  
Coupled Model ◽  
Tropical Pacific ◽  
Equatorial Region ◽  
Upper Ocean ◽  
Central Pacific ◽  
Intergovernmental Panel ◽  
Ocean Atmosphere ◽  
The Tropical Pacific

Abstract The coupled model of the Institute of Atmospheric Physics (IAP) is used to investigate the effects of extratropical cooling and warming on the tropical Pacific climate. The IAP coupled model is a fully coupled GCM without any flux correction. The model has been used in many aspects of climate modeling, including the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) climate change and paleoclimate simulations. In this study, the IAP coupled model is subjected to cooling or heating over the extratropical Pacific. As in an earlier study, the cooling and heating is imposed over the extratropical region poleward of 10°N–10°S. Consistent with earlier findings, an elevated (reduced) level of ENSO activity in response to an increase (decrease) in the cooling over the extratropical region is found. The changes in the time-mean structure of the equatorial upper ocean are also found to be very different between the case in which ocean–atmosphere is coupled over the equatorial region and the case in which the ocean–atmosphere over the equatorial region is decoupled. For example, in the uncoupled run, the thermocline water across the entire equatorial Pacific is cooled in response to an increase in the extratropical cooling. In the corresponding coupled run, the changes in the equatorial upper-ocean temperature in the extratropical cooling resemble a La Niña situation—a deeper thermocline in the western and central Pacific accompanied by a shallower thermocline in the eastern Pacific. Conversely, with coupling, the response of the equatorial upper ocean to extratropical cooling resembles an El Niño situation. These results ascertain the role of extratropical ocean in determining the amplitude of ENSO. The results also underscore the importance of ocean–atmosphere coupling in the interaction between the tropical Pacific and the extratropical Pacific.

Possible role of oceanic heat transport in Early Eocene climate

1995 ◽  
Vol 10 (2) ◽  
pp. 347-356 ◽  
Author(s):  
L. Cirbus Sloan ◽  
James C. G. Walker ◽  
T. C. Moore
Keyword(s):  
Heat Transport ◽  
Early Eocene ◽  
Oceanic Heat Transport

Northward oceanic heat transport in the main branch of the Norwegian Atlantic Current over the late Holocene

The Holocene ◽  
2017 ◽  
Vol 27 (7) ◽  
pp. 1034-1044 ◽  
Author(s):  
Andrea D Tegzes ◽  
Eystein Jansen ◽  
Torbjørn Lorentzen ◽  
Richard J Telford
Keyword(s):  
Heat Transport ◽  
Time Scales ◽  
Late Holocene ◽  
Meridional Overturning Circulation ◽  
The Arctic ◽  
Upper Ocean ◽  
Oceanic Heat Transport ◽  
The Past ◽  
Norwegian Margin ◽  
Atlantic Current

The Norwegian Atlantic Current represents the northernmost reaches of the (sub)surface limb of the Atlantic Meridional Overturning Circulation. Its shelf-edge branch, the Norwegian Atlantic Slope Current (NwASC), is of particular interest as it seems to be the main conduit for advected heat towards the Arctic. The objective of this study was to investigate northward oceanic heat transport in the NwASC on longer, geologically meaningful time scales. To this end, we reconstructed variations in the strength of the NwASC over the late Holocene using the sortable-silt method. We then analysed the statistical relationship between our palaeo-flow reconstructions and published upper-ocean hydrography proxy records from the same location on the mid-Norwegian Margin. Our sortable-silt time series show prominent multi-decadal to multi-centennial variability, but no clear long-term trend over the past 4200 years. These records we thus interpret to represent perturbations in a relatively stable late-Holocene mean flow. Our in-depth statistical analysis indicates that upper-ocean temperatures at the mid-Norwegian Margin may have varied independently from the strength of the NwASC on multi-decadal to multi-centennial time scales over the past few millennia.

scholarly journals The relative role of oceanic heat transport and orography on glacial climate

2006 ◽  
Vol 25 (7-8) ◽  
pp. 832-845 ◽  
Author(s):  
Vanya Romanova ◽  
Gerrit Lohmann ◽  
Klaus Grosfeld ◽  
Martin Butzin
Keyword(s):  
Heat Transport ◽  
Relative Role ◽  
Oceanic Heat Transport ◽  
Glacial Climate

scholarly journals Increasing Atlantic Ocean Heat Transport in the Latest Generation Coupled Ocean-Atmosphere Models: The Role of Air-Sea Interaction

2018 ◽  
Vol 123 (11) ◽  
pp. 8624-8637 ◽  
Author(s):  
Jeremy P. Grist ◽  
Simon A. Josey ◽  
Adrian L. New ◽  
Malcolm Roberts ◽  
Torben Koenigk ◽  
...  
Keyword(s):  
Atlantic Ocean ◽  
Heat Transport ◽  
Ocean Heat Transport ◽  
Ocean Atmosphere

Global warming pattern formation: the role of ocean heat uptake

2021 ◽  
pp. 1-46
Keyword(s):  
Pattern Formation ◽  
Coupled Model ◽  
Cooling Effect ◽  
Ocean Heat Uptake ◽  
Surface Warming ◽  
Warming Pattern ◽  
Ocean Atmosphere ◽  
Heat Uptake ◽  
Global Mean

Abstract This study investigates the formation mechanism of ocean surface warming pattern in response to a doubling CO2 with a focus on the role of ocean heat uptake (or ocean surface heat flux change, ΔQnet). We demonstrate that the transient patterns of surface warming and rainfall change simulated by the dynamic ocean-atmosphere coupled model (DOM) can be reproduced by the equilibrium solutions of the slab ocean-atmosphere coupled model (SOM) simulations when forced with the DOM ΔQnet distribution. The SOM is then used as a diagnostic, inverse modeling tool to decompose the CO2-induced thermodynamic warming effect and the ΔQnet (ocean heat uptake)-induced cooling effect. As ΔQnet is largely positive (i.e., downward into the ocean) in the subpolar oceans and weakly negative at the equator, its cooling effect is strongly polar amplified and opposes the CO2 warming, reducing the net warming response especially over Antarctica. For the same reason, the ΔQnet-induced cooling effect contributes significantly to the equatorially enhanced warming in all three ocean basins, while the CO2 warming effect plays a role in the equatorial warming of the eastern Pacific. The spatially varying component of ΔQnet, although globally averaged to zero, can effectively rectify and lead to decreased global mean surface temperature of a comparable magnitude as the global mean ΔQnet effect under transient climate change. Our study highlights the importance of air-sea interaction in the surface warming pattern formation and the key role of ocean heat uptake pattern.

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