Table 3 Comparison of modelled spatial and temporal δ18O-Tsurf slope and inferred LGM cooling

From: Reconciling glacial Antarctic water stable isotopes with ice sheet topography and the isotopic paleothermometer

Site (sector)

Ice Δδ18O

[‰]

Observed PD

slope [‰/°C]

Modelled PD

slope [‰/°C]

Modelled temporal slope [‰/°C]

Inferred

ΔT [°C]

Modelled

ΔT [°C]

EDML (1)

−6.3

0.79 (0.82)

0.85

0.73 ± 0.10 (33)

−8.9

−9.9

Dome F (2)

−4.9

0.81 (0.80)

0.87

0.68 ± 0.07 (33)

−7.4

−8.0

Dome B (3)

−5.0

0.91 (0.75)

0.88

0.43 ± 0.06 (33)

−8.0

−10.8

Vostok (3)

−4.8

0.91 (0.75)

0.88

0.48 ± 0.13 (33)

−7.7

−11.1

Law Dome (3)

−5.5

0.91

0.88

0.65 ± 0.08 (19)

−7.1a

−9.0

EDC (3)

−5.6

0.91 (0.75)

0.88

0.79 ± 0.07 (33)

−8.8

−8.0

Taylor Dome (4)

−4.0

0.70

0.97

0.68 ± 0.15 (31)

−7.1a

−8.3

Talos (4)

−5.5

0.70

0.97

0.66 ± 0.18 (33)

−9.3a

−9.6

Siple Dome (5)

−7.8

0.88

0.90

1.44 ± 0.47 (33)

−10.0a

−5.1

Byrd (5)

−7.3

0.88

0.90

0.65 ± 0.09 (33)

−9.4a

−13.7

WDC (5)

−7.3

0.88 (0.70)

0.90

0.70 ± 0.09 (33)

−11.9

−13.8

Dome A (2)

  

0.87

0.54 ± 0.09 (33)

 

−7.6

RICE (4)

  

0.97

1.04 ± 0.35 (27)

 

−3.9

Fletcher (6)

  

0.95

0.74 ± 0.18 (33)

 

−18.4

James Ross (6)

  

0.95

0.57 ± 0.03 (7)

 

−14.1

Berkner (6)

  

0.95

1.09 ± 0.19 (31)

 

−14.0

  1. The columns list the selected deep-drilling ice core sites, the measured LGM-PD Δδ18O, the observed PD slope for the sector within parenthesis the value used for the interpretation of the given ice core, the modelled PD slope in the corresponding sector of each ice core location, and the modelled temporal slope at the site. The number of grid boxes used for calculating the temporal slope is given in brackets. By default, 33 (=11 × 3) grid boxes centred on each drilling location are used. Numbers lower than 33 are caused by the coastal location of some ice cores (ocean grid points are neglected in all calculations). Correction for the prescribed glacial seawater change of 1‰ has been applied to LGM-PD Δδ18O values before temporal slope calculation. The second last column reports the LGM-PD temperature change ΔT as inferred from the measured LGM-PD Δδ18O (also corrected for an assumed glacial seawater δ18O change of +1‰) and the observed PD slope values used for the interpretation of the different cores. The last column reports the modelled LGM-PD temperature change ΔT at the different ice core sites. Further information: Data measured along the Dumont d’Urville- Dome C axis7 showing a δ18O/Ts slope of 0.75‰/°C has been used for Dome C2, Dome B42 and Vostok17. A slightly higher value of 0.85‰/°C is observed in the Dome Fuji sector but an average with the Vostok sector of 0.80‰/°C is taken into account by Watanabe et al.33 as this study focuses on the comparison between the Dome F and Vostok temperature records. A similar value of 0.82‰/°C is reported for Dronning Maud Land area and used for interpreting the EDML isotopic profile5. For the WAIS divide core, the temperature interpretation also uses isotopic profiles but calibrated using a measured borehole temperature profile, the estimate of the LGM cooling of 11.3 ± 1.8 °C[45] would be consistent with the use of a slope close from 0.7‰/°C
  2. aInferred ΔT values have been calculated using the observed PD slope in the related sector
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