Total air content in the NGRIP and isotopic signatures of N2O in the Talos Dome ice core ...

• Main Author: Eicher, Olivier
• Format: Thesis
• Language: unknown
• Published: :unas 2016
• Subjects: 530 Physics; Antarctic; Greenland; Tac; Talos Dome; Antarc*; Greenland ice core; Greenland Ice core Project; ice core; NGRIP; North Greenland; North Greenland Ice Core Project
• Online Access: https://dx.doi.org/10.48350/192572; https://boris.unibe.ch/192572/

This thesis contains two thematic key aspects. The main focus is total air content (TAC) in the North Greenland Ice Core Project (NGRIP) ice core. We present the first TAC record over an entire Greenland ice core, consisting of 1688 datapoints in total. The TAC record shows a local insolation signature, an effect known for Antarctic TAC records, now independently confirmed for Greenland by our study. We are also the first showing direct imprint of fast warmings, the Dansgaard-Oeschger (DO) events, in TAC. This TAC response is larger than expected considering only changes in air density by local temperature and atmospheric pressure changes as a driver, pointing to a transient firnification response in pore volume. We hypothesize that the transient firnification response is caused by the accumulation-induced increase in the load on the firn at bubble close-off, while at close-off temperature changes are still small. Using a firn model, we provide an upper limit of this effect. Our results contribute to the ...