Modelling glacial climatic millennial-scale variability related to changes in the Atlantic meridional overturning circulation: a review

Kageyama, Masa; Paul, André; Roche, Didier M.; Meerbeeck, Cédric J. Van

doi:10.1016/j.quascirev.2010.05.029

Cited by 114 publications

(120 citation statements)

References 168 publications

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“…Broecker et al 1993;McManus et al 2004;Gherardi et al 2005). This is corroborated by numerous coupled atmosphere-ocean model experiments, showing that the fresh melting water from these icebergs can trigger (partial) ''shut down'' of the meridional overturning circulation (MOC) (Kageyama et al 2010 and references therein; e. g. Hewitt et al 2006). In these so-called hosing studies, the freshening effect of the melting icebergs is typically simplified to homogeneous and instantaneous dumping of freshwater on a designated ocean area that corresponds to the Ruddiman belt.…”

Section: Introductionmentioning

confidence: 55%

Simulating Heinrich event 1 with interactive icebergs

2012

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During the last glacial, major abrupt climate events known as Heinrich events left distinct fingerprints of ice rafted detritus, and are thus associated with iceberg armadas; the release of many icebergs into the North Atlantic Ocean. We simulated the impact of a large armada of icebergs on glacial climate in a coupled atmosphereocean model. In our model, dynamic-thermodynamic icebergs influence the climate through two direct effects. First, melting of the icebergs causes freshening of the upper ocean, and second, the latent heat used in the phase-transition of ice to water results in cooling of the iceberg surroundings. This cooling effect of icebergs is generally neglected in models. We investigated the role of the latent heat by performing a sensitivity experiment in which the cooling effect is switched off. At the peak of the simulated Heinrich event, icebergs lacking the latent heat flux are much less efficient in shutting down the meridional overturning circulation than icebergs that include both the freshening and the cooling effects. The cause of this intriguing result must be sought in the involvement of a secondary mechanism: facilitation of sea-ice formation, which can disturb deep water production at key convection sites, with consequences for the thermohaline circulation. We performed additional sensitivity experiments, designed to explore the effect of the more plausible distribution of the dynamic icebergs' melting fluxes compared to a classic hosing approach with homogeneous spreading of the melt fluxes over a section in the mid-latitude North Atlantic (NA) Ocean. The early response of the climate system is much stronger in the iceberg experiments than in the hosing experiments, which must be a distribution-effect: the dynamically distributed icebergs quickly affect western NADW formation, which synergizes with direct sea-ice facilitation, causing an earlier sea-ice expansion and climatic response. Furthermore, compared to dynamic-thermodynamic icebergs, a homogeneous hosing overestimates the fresh water flux in the Eastern Ruddiman belt, causing a fresh anomaly in the Eastern North Atlantic, leading to a delayed recovery of the circulation after the event.

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Section: Introductionmentioning

confidence: 55%

Simulating Heinrich event 1 with interactive icebergs

2012

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“…Model inter-comparisons show that not all models are sensitive to freshwater hosing in the same manner (Stouffer et al, 2006;Kageyama et al, 2010). For example, while all models show a shutdown of the thermohaline circulation under a 1.0 Sv hosing (Stouffer et al, 2006), they differ in response when the forcing is closer to what is currently estimated for Heinrich events, i.e.…”

Section: Modelling the Impact Of Iceberg And Meltwater Events On The mentioning

confidence: 80%

“…Consequently, most models have been run with an input of freshwater, termed 'hosing experiments', Ganopolski and Rahmstorf, 2001;Stouffer et al 2006) in the Ruddiman belt, with different sets of magnitudes used to evaluate the sensitivity of the models to a freshwater perturbation (see Kageyama et al, 2010, for a review).…”

Section: Modelling the Impact Of Iceberg And Meltwater Events On The mentioning

confidence: 99%

“…Ocean response is also highly sensitive to the location of meltwater injection (Condron and Winsor, 2012) and the spatial pattern of freshwater injection needs to be taken into account (Jongma et al, 2013). A related complication is the apparent sensitivity of the modelled climate system response to meltwater injection to the background state of the ocean-climate system (Kageyama et al, 2010;2013).…”

Section: Freshwater Impacts On the Ocean-climate Systemmentioning

confidence: 99%

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On the reconstruction of palaeo-ice sheets: Recent advances and future challenges

Stokes

Tarasov

Blomdin

et al. 2015

Quaternary Science Reviews

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148

104

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“…An example of such a method is given in Bethke et al (2012). The second recommendation is to analyse the model response to freshwater fluxes in different geographical zones and for different flux magnitudes to better understand the nature of the responses of individual models (Kageyama et al, 2010;Roche et al, 2007b;Stouffer et al, 2006), and to repeat this for different climate settings (Van Meerbeeck et al, 2011).…”

Section: Working Group 3: Modelling Mechanisms Of Past Changementioning

confidence: 99%

Dating, synthesis, and interpretation of palaeoclimatic records of the Last Glacial cycle and model-data integration: advances by the INTIMATE (INTegration of Ice-core, MArine and TErrestrial records) COST Action ES0907

Rasmussen

Birks²,

Blockley³

et al. 2014

Quaternary Science Reviews

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Since 2010, the INTIMATE (INTegration of Ice-core, MArine and TErrestrial records) network has been operating as a COST Action (designated ES0907). This paper outlines the accomplishments of the INTIMATE COST Action in the context of how the INTIMATE ideas have evolved during the network's twenty-year life 2 span, and highlights a number of challenges that can guide further work. In the second part of the paper, the contributions that comprise this INTIMATE special issue are introduced.

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Modelling glacial climatic millennial-scale variability related to changes in the Atlantic meridional overturning circulation: a review

Cited by 114 publications

References 168 publications

Simulating Heinrich event 1 with interactive icebergs

Simulating Heinrich event 1 with interactive icebergs

On the reconstruction of palaeo-ice sheets: Recent advances and future challenges

Dating, synthesis, and interpretation of palaeoclimatic records of the Last Glacial cycle and model-data integration: advances by the INTIMATE (INTegration of Ice-core, MArine and TErrestrial records) COST Action ES0907

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