scholarly journals Can the Last Glacial Maximum constrain climate sensitivity?

2012 ◽  
Vol 39 (24) ◽  
Author(s):  
J. C. Hargreaves ◽  
J. D. Annan ◽  
M. Yoshimori ◽  
A. Abe‐Ouchi
Keyword(s):  
Last Glacial Maximum ◽  
Climate Sensitivity ◽  
Glacial Maximum ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

scholarly journals A global climatology of the ocean surface during the Last Glacial Maximum mapped on a regular grid (GLOMAP)

2021 ◽  
Vol 17 (2) ◽  
pp. 805-824
Author(s):  
André Paul ◽  
Stefan Mulitza ◽  
Rüdiger Stein ◽  
Martin Werner
Keyword(s):  
Sea Ice ◽  
Last Glacial Maximum ◽  
Climate Sensitivity ◽  
Ocean Surface ◽  
Glacial Maximum ◽  
Sea Ice Extent ◽  
Equilibrium Climate Sensitivity ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract. We present a climatology of the near-sea-surface temperature (NSST) anomaly and the sea-ice extent during the Last Glacial Maximum (LGM, 23 000–19 000 years before present) mapped on a global regular 1∘×1∘ grid. It is an extension of the Glacial Atlantic Ocean Mapping (GLAMAP) reconstruction of the Atlantic NSST based on the faunal and floral assemblage data of the Multiproxy Approach for the Reconstruction of the Glacial Ocean Surface (MARGO) project and several recent estimates of the LGM sea-ice extent. Such a gridded climatology is highly useful for the visualization of the LGM climate, calculation of global and regional NSST averages, and estimation of the equilibrium climate sensitivity, as well as a boundary condition for atmospheric general circulation models. The gridding of the sparse NSST reconstruction was done in an optimal way using the Data-Interpolating Variational Analysis (DIVA) software, which takes into account the uncertainty in the reconstruction and includes the calculation of an error field. The resulting Glacial Ocean Map (GLOMAP) confirms the previous findings by the MARGO project regarding longitudinal and meridional NSST differences that were greater than today in all oceans. Taken at face value, the estimated global and tropical cooling would imply an equilibrium climate sensitivity at the lower end of the currently accepted range. However, because of anticipated changes in the seasonality and thermal structure of the upper ocean during the LGM as well as uneven spatial sampling, the estimated cooling and implied climate sensitivity are likely to be biased towards lower values.

Dependency of Feedbacks on Forcing and Climate State in Physics Parameter Ensembles

2011 ◽  
Vol 24 (24) ◽  
pp. 6440-6455 ◽  
Author(s):  
Masakazu Yoshimori ◽  
Julia C. Hargreaves ◽  
James D. Annan ◽  
Tokuta Yokohata ◽  
Ayako Abe-Ouchi
Keyword(s):  
Last Glacial Maximum ◽  
Climate Sensitivity ◽  
Glacial Maximum ◽  
Lapse Rate ◽  
Climate Projections ◽  
Parameter Uncertainties ◽  
State Dependency ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract Climate sensitivity is one of the most important metrics for future climate projections. In previous studies the climate of the last glacial maximum has been used to constrain the range of climate sensitivity, and similarities and differences of temperature response to the forcing of the last glacial maximum and to idealized future forcing have been investigated. The feedback processes behind the response have not, however, been fully explored in a large model parameter space. In this study, the authors first examine the performance of various feedback analysis methods that identify important feedbacks for a physics parameter ensemble in experiments simulating both past and future climates. The selected methods are then used to reveal the relationship between the different ensemble experiments in terms of individual feedback processes. For the first time, all of the major feedback processes for an ensemble of paleoclimate simulations are evaluated. It is shown that the feedback and climate sensitivity parameters depend on the nature of the forcing and background climate state. The forcing dependency arises through the shortwave cloud feedback while the state dependency arises through the combined water vapor and lapse-rate feedback. The forcing dependency is, however, weakened when the feedback is estimated from the forcing that includes tropospheric adjustments. Despite these dependencies, past climate can still be used to provide a useful constraint on climate sensitivity as long as the limitation is properly taken into account because the strength of each feedback correlates reasonably well between the ensembles. It is, however, shown that the physics parameter ensemble does not cover the range of results simulated by structurally different models, which suggests the need for further study exploring both structural and parameter uncertainties.

Climate Sensitivity Estimated from Temperature Reconstructions of the Last Glacial Maximum

Science ◽  
2011 ◽  
Vol 334 (6061) ◽  
pp. 1385-1388 ◽  
Author(s):  
A. Schmittner ◽  
N. M. Urban ◽  
J. D. Shakun ◽  
N. M. Mahowald ◽  
P. U. Clark ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Climate Sensitivity ◽  
Glacial Maximum ◽  
Last Glacial ◽  
Temperature Reconstructions ◽  
The Last Glacial Maximum ◽  
The Last Glacial

scholarly journals A global climatology of the ocean surface during the Last Glacial Maximum mapped on a regular grid (GLOMAP)

2020 ◽  
Author(s):  
André Paul ◽  
Stefan Mulitza ◽  
Rüdiger Stein ◽  
Martin Werner
Keyword(s):  
Sea Ice ◽  
Last Glacial Maximum ◽  
Climate Sensitivity ◽  
Ocean Surface ◽  
Glacial Maximum ◽  
Sea Ice Extent ◽  
Equilibrium Climate Sensitivity ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract. We present a climatology of the sea-surface temperature (SST) anomaly and the sea-ice extent during the Last Glacial Maximum (LGM, 23 000–19 000 years before present) mapped on a global regular 1° × 1° grid. It is an extension of the Glacial Atlantic Ocean Mapping (GLAMAP) reconstruction of the Atlantic SST based on the results of the Multiproxy Approach for the Reconstruction of the Glacial Ocean Surface (MARGO) project and several recent estimates of the LGM sea-ice extent. Such a gridded climatology is highly useful for the visualization of the LGM climate, calculation of global and regional SST averages and estimation of the equilibrium climate sensitivity, as well as a boundary condition for atmospheric general circulation models. The gridding of the sparse SST reconstruction was done in an optimal way using the Data-Interpolating Variational Analysis (DIVA) software, which takes into account the uncertainty on the reconstruction and includes the calculation of an error field. The resulting Glacial Ocean Map (GLOMAP) confirmed the previous findings by the MARGO project regarding longitudinal and meridional SST differences that were greater than today in all oceans and an equilibrium climate sensitivity at the lower end of the currently accepted range.

scholarly journals Response to Comment on "Climate Sensitivity Estimated from Temperature Reconstructions of the Last Glacial Maximum"

Science ◽  
2012 ◽  
Vol 337 (6100) ◽  
pp. 1294-1294 ◽  
Author(s):  
A. Schmittner ◽  
N. M. Urban ◽  
J. D. Shakun ◽  
N. M. Mahowald ◽  
P. U. Clark ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Climate Sensitivity ◽  
Glacial Maximum ◽  
Last Glacial ◽  
Temperature Reconstructions ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Does the Last Glacial Maximum constrain climate sensitivity?

2006 ◽  
Vol 33 (18) ◽  
pp. n/a-n/a ◽  
Author(s):  
M. Crucifix
Keyword(s):  
Last Glacial Maximum ◽  
Climate Sensitivity ◽  
Glacial Maximum ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial
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