Towards an understanding of the controls on δO2/N2 variability in ice core records

Processes controlling pore closure are broadlyunderstood yetdefining the physical mechanismsdrivingelemental fractionation remains ambiguous. It hasindeedbeen shown that the pore closure processes lead to a decrease of concentration of small size molecules (e.g.O2,Ar, Ne) in the bubbles. Moreover, ice coreδO2/N2records shows a clear link with local summer solstice insolation and hence makes it a powerful dating tool.However, investigations towards a mechanistic understanding ofδO2/N2and summer solstice insolation suggests local climatic conditions may also be important.We compiledδO2/N2records from several polar ice cores and found a link betweenδO2/N2and temperature and/or accumulation rate, in addition to the influence of the summer solstice insolation intensity. Using the Crocus snowpack model, we carry out sensitivity tests to identify the response of near-surface snow properties to changes in insolation, accumulation rate and air temperature.
The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)