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

P. Kindler, M. Guillevic, M. Baumgartner, J. Schwander, A. Landais, M. Leuenberger
2014 Climate of the Past  
<p><strong>Abstract.</strong> In order to reconstruct the temperature of the North Greenland Ice Core Project (NGRIP) site, new measurements of δ<sup>15</sup>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<sup>15</sup>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
more » ... sand years before 2000 AD) including every DO event based on δ<sup>15</sup>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<sup>18</sup>O<sub>ice</sub> data confirms that the isotopic composition of the stadial was strongly influenced by seasonality. We evidence an anticorrelation between the variations of the δ<sup>18</sup>O<sub>ice</sub> 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.</p>
doi:10.5194/cp-10-887-2014 fatcat:mzmwfn464vc5tbtwajbriqlqku