Linking glacial and future climates through an ensemble of GCM simulations

Hargreaves, J. C.; Abe‐Ouchi, Ayako; Annan, J. D.

doi:10.5194/cp-3-77-2007

Cited by 86 publications

(98 citation statements)

References 20 publications

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“…In these SH latitudes, the reduction of the atmospheric heat gain is as large as the surface cooling, which suggests that CO 2 and water vapour contribute most to the cooling. This is consistent with several studies suggesting that the polar amplification over Antarctica may provide useful evidence on climate sensitivity (Manabe and Broccoli, 1985;Masson-Delmotte et al, 2006), although the relationship is complex Hargreaves et al, 2007).…”

Section: Results For the Last Glacial Maximumsupporting

confidence: 78%

Results of PMIP2 coupled simulations of the Mid-Holocene and Last Glacial Maximum – Part 2: feedbacks with emphasis on the location of the ITCZ and mid- and high latitudes heat budget

et al. 2007

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Abstract.A set of coupled ocean-atmosphere (-vegetation) simulations using state of the art climate models is now available for the Last Glacial Maximum (LGM) and the MidHolocene (MH) through the second phase of the Paleoclimate Modeling Intercomparison Project (PMIP2). Here we quantify the latitudinal shift of the location of the Intertropical Convergence Zone (ITCZ) in the tropical regions during boreal summer and the change in precipitation in the northern part of the ITCZ. For both periods the shift is more pronounced over the continents and East Asia. The maritime continent is the region where the largest spread is found between models. We also clearly establish that the larger the increase in the meridional temperature gradient in the tropical Atlantic during summer at the MH, the larger the change in precipitation over West Africa. The vegetation feedback is however not as large as found in previous studies, probably due to model differences in the control simulation. Finally, we show that the feedback from snow and sea-ice at mid and high latitudes contributes for half of the cooling in the Northern Hemisphere for the LGM, with the remaining being achieved by the reduced CO 2 and water vapour in the Correspondence to: P. Braconnot (pascale.braconnot@cea.fr) atmosphere. For the MH the snow and albedo feedbacks strengthen the spring cooling and enhance the boreal summer warming, whereas water vapour reinforces the late summer warming. These feedbacks are modest in the Southern Hemisphere. For the LGM most of the surface cooling is due to CO 2 and water vapour.

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Section: Results For the Last Glacial Maximumsupporting

confidence: 78%

Results of PMIP2 coupled simulations of the Mid-Holocene and Last Glacial Maximum – Part 2: feedbacks with emphasis on the location of the ITCZ and mid- and high latitudes heat budget

et al. 2007

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“…It was found that the strength of some of the fast feedbacks depends on the background climate state. This is in agreement with other model-based approaches, which proposed a state dependency of water vapour (Meraner et al, 2013) or clouds (Crucifix, 2006;Hargreaves et al, 2007). Distinguishing different climate regimes in palaeodata covering the last 800 000 years (0.8 Myr), the time for which ice core records exist, von der Heydt et al (2014) revealed a ∼ 36 % larger S [CO 2 ,LI] for "warm" background climates when compared to "cold" climates.…”

supporting

confidence: 81%

“…Crucifix, 2006;Hargreaves et al, 2007;Yoshimori et al, 2011;Yin and Berger, 2012;Caballero and Huber, 2013;Goldner et al, 2013;Kutzbach et al, 2013;Meraner et al, 2013) and palaeodata-based (PALAEOSENS-Project Members, 2012;von der Heydt et al, 2014) approaches have already indicated that S varies for different background climates; see also a recent review of Knutti and Rugenstein (2015) on the limits of linear models to constrain climate sensitivity. The majority of simulation studies shows a rise in climate sensitivity for a warmer background climate.…”

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confidence: 99%

On the state dependency of the equilibrium climate sensitivity during the last 5 million years

et al. 2015

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Abstract.It is still an open question how equilibrium warming in response to increasing radiative forcing -the specific equilibrium climate sensitivity S -depends on background climate. We here present palaeodata-based evidence on the state dependency of S, by using CO 2 proxy data together with a 3-D ice-sheet-model-based reconstruction of land ice albedo over the last 5 million years (Myr). We find that the land ice albedo forcing depends non-linearly on the background climate, while any non-linearity of CO 2 radiative forcing depends on the CO 2 data set used. This nonlinearity has not, so far, been accounted for in similar approaches due to previously more simplistic approximations, in which land ice albedo radiative forcing was a linear function of sea level change. The latitudinal dependency of icesheet area changes is important for the non-linearity between land ice albedo and sea level. In our set-up, in which the radiative forcing of CO 2 and of the land ice albedo (LI) is combined, we find a state dependence in the calculated specific equilibrium climate sensitivity, S [CO 2 ,LI] , for most of the Pleistocene (last 2.1 Myr). During Pleistocene intermediate glaciated climates and interglacial periods, S [CO 2 ,LI] is on average ∼ 45 % larger than during Pleistocene full glacial conditions. In the Pliocene part of our analysis (2.6-5 Myr BP) the CO 2 data uncertainties prevent a well-supported calculation for S [CO 2 ,LI] , but our analysis suggests that during times without a large land ice area in the Northern Hemisphere (e.g. before 2.82 Myr BP), the specific equilibrium climate sensitivity, S [CO 2 ,LI] , was smaller than during interglacials of the Pleistocene. We thus find support for a previously proposed state change in the climate system with the widespread appearance of northern hemispheric ice sheets. This study points for the first time to a so far overlooked non-linearity in the land ice albedo radiative forcing, which is important for similar palaeodata-based approaches to calculate climate sensitivity. However, the implications of this study for a suggested warming under CO 2 doubling are not yet entirely clear since the details of necessary corrections for other slow feedbacks are not fully known and the uncertainties that exist in the ice-sheet simulations and global temperature reconstructions are large.

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“…Masson-Delomtte et al, 2006;Kageyama et al, 2006;Braconnot et al , 2007;Hargreaves et al, 2007;Roche et al, 2007;Weber et al, 2007). The objective of this study is to investigate the surface climate and atmospheric field over East Asia and the North Pacific during the LGM by comparing the results obtained using the different CGCMs in the PMIP2 database and the paleoclimatic reconstructions.…”

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confidence: 99%

The LGM surface climate and atmospheric circulation over East Asia and the North Pacific in the PMIP2 coupled model simulations

Yanase

Abe‐Ouchi

2007

Clim. Past

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Abstract. The surface conditions and atmospheric circulation over East Asia and the North Pacific during the last glacial maximum have been investigated using outputs from several coupled atmosphere-ocean general circulation model in the PMIP2 database. During the boreal summer, the weakening of the high pressure system over the North Pacific and less precipitation over East Asia are found in most models. The latter can be attributed to reduced moisture transport. During the boreal winter, an intensification of the Aleutian low and southward shift of the westerly jet stream in the upper troposphere are found in most models.Some of the results in the present study seem to be consistent with the paleoclimatic reconstructions in the previous studies: pollen and lake-status records suggest dry climate over East Asia during the last glacial maximum, and part of the dust record has a signal that the East Asian winter monsoon was more strong and the westerly jet stream in the upper troposphere was further south during the last glacial maximum than at the present day. This result confirms that a coupled atmosphere-ocean general circulation model is a promising tool to understand not only the global climate but also the regional climate in the past.

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Linking glacial and future climates through an ensemble of GCM simulations

Cited by 86 publications

References 20 publications

Results of PMIP2 coupled simulations of the Mid-Holocene and Last Glacial Maximum – Part 2: feedbacks with emphasis on the location of the ITCZ and mid- and high latitudes heat budget

Results of PMIP2 coupled simulations of the Mid-Holocene and Last Glacial Maximum – Part 2: feedbacks with emphasis on the location of the ITCZ and mid- and high latitudes heat budget

On the state dependency of the equilibrium climate sensitivity during the last 5 million years

The LGM surface climate and atmospheric circulation over East Asia and the North Pacific in the PMIP2 coupled model simulations

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