The synoptic climatology of ablation on a New Zealand glacier

Abstract

Abstract Local scale ablation and energy budget measurements are reported for the Ivory glacier in the Southern Alps of New Zealand over 53 days during two consecutive summer periods. Ablation averaged 38 mm day −1 , but varied from less than 10 mm day −1 to over 70 mm day −1 . Radiation supplied 52% of the energy for glacier melt, with the convective fluxes contributing most of the remainder. The results are related to large scale synoptic weather patterns over the southwest Pacific region. Different synoptic situations generate distinctive energy budgets, with radiation important during southerly circulation patterns and the convective fluxes relatively more important with northerly circulation patterns. These findings are discussed in the context of the retreat of New Zealand glaciers this century and possible circulation changes.