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

• Published in: Climate of the Past
• Main Authors: Kindler, P., Guillevic, M., Baumgartner, M., Schwander, J., Landais, A., Leuenberger, M.
• Format: Text
• Language: English
• Published: 2018
• Subjects: Greenland; Greenland ice core; Greenland Ice core Project; ice core; Ice Sheet; NGRIP; North Greenland; North Greenland Ice Core Project
• Online Access: https://doi.org/10.5194/cp-10-887-2014; https://cp.copernicus.org/articles/10/887/2014/

In order to reconstruct the temperature of the North Greenland Ice Core Project (NGRIP) site, new measurements of δ 15 N 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 15 N 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 15 N 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 18 O 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 18 O 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.