A first estimate of mountain permafrost distribution in the Mount Cook region of New Zealand’s southern alps

Abstract

The heavily glaciated Mount Cook Region of New Zealand has experienced several recent large rock instabilities,
but permafrost conditions related to these events remain unknown. This work presents the first systematic approach
for investigating the distribution of mountain permafrost in New Zealand. At this level of the investigation, a firstorder estimate is based upon the adaptation of established topo-climatic relationships from the European Alps. In the southeast of the study region, the permafrost estimate gives a reasonable correspondence with mapped rock glacier distribution but the maximum elevation of vegetation growth is situated 200 m beneath the lower limit of estimated permafrost. Extreme climate gradients exist and towards the humid northwest, where rock glaciers are absent and vegetation patterns give an unclear climate signal, large uncertainties remain. Data currently being recorded from a network of rock wall temperature measurements will help remove this uncertainty, and will allow distribution modeling that better accounts for the topographic complexities of this steep alpine region.