Temperature reconstruction from 10 to 120 kyr b2k from the NGRIP ice core

Kindler, P.; Guillevic, M.; Baumgartner, M.; Schwander, J.; Landais, A.; Leuenberger, M.

In order to reconstruct the temperature of the North Greenland Ice Core Project (NGRIP) site, new measurements of δ 15N have been performed covering the time period from the beginning of the Holocene to Dansgaard–Oeschger (DO) event 8. Together with previously measured and mostly published δ 15N data, we present for the first time a NGRIP temperature reconstruction for the whole last glacial period from 10 to 120 kyr b2k (thousand years before 2000 AD) including every DO event based on δ 15N isotope measurements combined with a firn densification and heat diffusion model. The detected temperature rises at the onset of DO events range from 5 °C (DO 25) up to 16.5 °C (DO 11) with an uncertainty of ±3 °C. To bring measured and modelled data into agreement, we had to reduce the accumulation rate given by the NGRIP ss09sea06bm timescale in some periods by 30 to 35%, especially during the last glacial maximum. A comparison between reconstructed temperature and δ 18O ice data confirms that the isotopic composition of the stadial was strongly influenced by seasonality. We evidence an anticorrelation between the variations of the δ 18O ice sensitivity to temperature (referred to as α) and obliquity in agreement with a simple Rayleigh distillation model. Finally, we suggest that α might be influenced by the Northern Hemisphere ice sheet volume.

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Kindler, P. / Guillevic, M. / Baumgartner, M. / et al: Temperature reconstruction from 10 to 120 kyr b2k from the NGRIP ice core. 2014. Copernicus Publications.

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