Climate sensitivity of Franz Josef Glacier, New Zealand, as revealed by numerical modeling

The sensitivity of Franz Josef Glacier is studied with a numerical ice-flow model. The model calculates ice mass flux along a central flow line and deals with the three-dimensional geometry in a parameterized way. Forcing is provided through a mass balance model that generates specific balance from climatological input data. Because of the very large mass turnover, e-folding response times are short: about 15 yr for ice volume and about 25 yr for glacier length. The sensitivity of glacier length to uniform warming is about 1.5 km K-l. The sensitivity to uniform changes in precipitation is about 0.05 km %(-1), implying that a 30% increase in precipitation would be needed to compensate for a 1 K warming.