Melt layers in ice cores

Warming surface temperatures result in surface melt, which can percolate through ice layers destroying paleoclimate information contained in ice cores. Antarctic surface melt is generally small, but there is growing evidence of increasing melt episodes in coastal regions and over large parts of West Antarctica. The aim of this PhD is to investigate the extent to which surface melt influences pore size and ice structure and how this influences the chemical and isotopic records used to reconstruct past climate. We will utilize existing ice cores from the sub-Antarctic islands (including Bouvet, Peter 1st and Balleny), the Antarctic Peninsula and West Antarctica. 3D pore and ice structure will be measured, during melt and non-melt events, using a unique X-ray-microfocus computer tomograph (micro CT) operating in a -20 cold lab. The aim is to 1) determine the influence of melt on pore size and ice structure, 2) investigate the influence of pore structure, and melt on chemical and isotopic species commonly employed to reconstruct past climate. CT scans will be compared with chemistry data, analyzed using continuous flow analysis (CFA) and ion chromatography.