Last Glacial Maximum climate in New Zealand inferred from a modelled Southern Alps icefield

Published: Aug 1, 2012 by The PISM Authors

In an attempt to constrain the climate of the Last Glacial Maximum period (LGM, c. 30–20 ka before present), a simulation of the New Zealand Southern Alps icefield is presented. PISM is applied at 500 m-resolution using empirical glaciological, climatological and geological data specific to the model domain, the entire icefield. An LGM cooling of at least 6–6.5 °C is necessary to bring about valley glaciers that extend beyond the mountains. However, climate–topography thresholds related to the elevation and hypsometry of individual catchments control the gradient of the rate of glacier expansion in the domain. In order to remain within geologically-reconstructed LGM limits we find that the LGM cooling was most likely associated with a precipitation regime up to 25% drier than today.