Sensitivity of climate response to variations in freshwater hosing location

Kleinen, Thomas; Osborn, Timothy J.; Briffa, Keith R.

doi:10.1007/s10236-009-0189-2

Cited by 23 publications

(23 citation statements)

References 54 publications

(67 reference statements)

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“…Therefore, our model experiments do not support the idea that higher summer SSTs were caused by increased inflow of warm Atlantic waters as proposed by Risebrobakken et al (2011). However, in other modelling studies -for instance Swingedouw et al (2012), Kleinen et al (2009) andStouffer et al (2006) -such increase in warm inflow is simulated in response to surface ocean freshening.…”

Section: Mechanisms Behind Sst Patternscontrasting

confidence: 79%

The Holocene thermal maximum in the Nordic Seas: the impact of Greenland Ice Sheet melt and other forcings in a coupled atmosphere–sea-ice–ocean model

Blaschek¹,

Renssen²

2013

Clim. Past

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Abstract. The relatively warm early Holocene climate in the Nordic Seas, known as the Holocene thermal maximum (HTM), is often associated with an orbitally forced summer insolation maximum at 10 ka BP. The spatial and temporal response recorded in proxy data in the North Atlantic and the Nordic Seas reveals a complex interaction of mechanisms active in the HTM. Previous studies have investigated the impact of the Laurentide Ice Sheet (LIS), as a remnant from the previous glacial period, altering climate conditions with a continuous supply of melt water to the Labrador Sea and adjacent seas and with a downwind cooling effect from the remnant LIS. In our present work we extend this approach by investigating the impact of the Greenland Ice Sheet (GIS) on the early Holocene climate and the HTM. Reconstructions suggest melt rates of 13 mSv for 9 ka BP, which result in our model in an ocean surface cooling of up to 2 K near Greenland. Reconstructed summer SST gradients agree best with our simulation including GIS melt, confirming that the impact of the early Holocene GIS is crucial for understanding the HTM characteristics in the Nordic Seas area. This implies that modern and near-future GIS melt can be expected to play an active role in the climate system in the centuries to come.

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Section: Mechanisms Behind Sst Patternscontrasting

confidence: 79%

The Holocene thermal maximum in the Nordic Seas: the impact of Greenland Ice Sheet melt and other forcings in a coupled atmosphere–sea-ice–ocean model

Blaschek¹,

Renssen²

2013

Clim. Past

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“…Under stronger, more uniform conditions of northern Atlantic freshwater hosing, similar decreases in SST and SSS in the surrounds of the UK have been found to be associated with freshwater "leakage" from the sub-polar gyre (Swingedouw et al, 2013). The wider patterns of change in North Atlantic SSS and SST are also consistent with, albeit weaker than, those found in other freshwater hosing experiments with HadCM3 (Kleinen et al, 2009;Swingedouw et al, 2013). Despite the local freshening and warming patterns in the North Atlantic and Barents Sea respectively, there are no significant changes to the sea ice area in our simulation.…”

Section: North Atlantic Case Study: Patterns Of Change Most Strongly supporting

confidence: 73%

The land-ice contribution to 21st-century dynamic sea level rise

et al. 2014

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Abstract. Climate change has the potential to influence global mean sea level through a number of processes including (but not limited to) thermal expansion of the oceans and enhanced land ice melt. In addition to their contribution to global mean sea level change, these two processes (among others) lead to local departures from the global mean sea level change, through a number of mechanisms including the effect on spatial variations in the change of water density and transport, usually termed dynamic sea level changes.In this study, we focus on the component of dynamic sea level change that might be given by additional freshwater inflow to the ocean under scenarios of 21st-century land-based ice melt. We present regional patterns of dynamic sea level change given by a global-coupled atmosphere-ocean climate model forced by spatially and temporally varying projected ice-melt fluxes from three sources: the Antarctic ice sheet, the Greenland Ice Sheet and small glaciers and ice caps. The largest ice melt flux we consider is equivalent to almost 0.7 m of global mean sea level rise over the 21st century. The temporal evolution of the dynamic sea level changes, in the presence of considerable variations in the ice melt flux, is also analysed.We find that the dynamic sea level change associated with the ice melt is small, with the largest changes occurring in the North Atlantic amounting to 3 cm above the global mean rise. Furthermore, the dynamic sea level change associated with the ice melt is similar regardless of whether the simulated ice fluxes are applied to a simulation with fixed CO 2 or under a business-as-usual greenhouse gas warming scenario of increasing CO 2 .

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“…An earlier modelling study (Kleinen et al, 2009) also depicted surface warming of the Nordic Seas in response to a freshwater perturbation, independently from the location of the freshwater input. It was attributed to the subsurface propagation of warm Atlantic water masses beneath the cold North Atlantic meltwater lid (resulting from the freshwater input) up to the Norwegian Sea, where they re-emerge and mix with ambient waters.…”

Section: Resultsmentioning

confidence: 87%

“…1d). This freshwater lid has two important consequences: (i) it prevents oceanic vertical mixing which normally transfers winter surface cooling (due to atmospheric heat fluxes) into subsurface, and (ii) it induces hydrographical reorganizations where subpolar gyre transport decreases but water-mass transport from the subtropics into the Nordic Seas increases, especially along the eastern North Atlantic boundary (see Hátún et al, 2005;Kleinen et al, 2009, and Fig. S6).…”

Section: Resultsmentioning

confidence: 99%

Regional seesaw between the North Atlantic and Nordic Seas during the last glacial abrupt climate events

et al. 2017

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Abstract. Dansgaard-Oeschger oscillations constitute one of the most enigmatic features of the last glacial cycle. Their cold atmospheric phases have been commonly associated with cold sea-surface temperatures and expansion of sea ice in the North Atlantic and adjacent seas. Here, based on dinocyst analyses from the 48-30 ka interval of four sediment cores from the northern Northeast Atlantic and southern Norwegian Sea, we provide direct and quantitative evidence of a regional paradoxical seesaw pattern: cold Greenland and North Atlantic phases coincide with warmer sea-surface conditions and shorter seasonal sea-ice cover durations in the Norwegian Sea as compared to warm phases. Combined with additional palaeorecords and multi-model hosing simulations, our results suggest that during cold Greenland phases, reduced Atlantic meridional overturning circulation and cold North Atlantic sea-surface conditions were accompanied by the subsurface propagation of warm Atlantic waters that reemerged in the Nordic Seas and provided moisture towards Greenland summit.

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Sensitivity of climate response to variations in freshwater hosing location

Cited by 23 publications

References 54 publications

The Holocene thermal maximum in the Nordic Seas: the impact of Greenland Ice Sheet melt and other forcings in a coupled atmosphere–sea-ice–ocean model

The Holocene thermal maximum in the Nordic Seas: the impact of Greenland Ice Sheet melt and other forcings in a coupled atmosphere–sea-ice–ocean model

The land-ice contribution to 21st-century dynamic sea level rise

Regional seesaw between the North Atlantic and Nordic Seas during the last glacial abrupt climate events

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