Ice dynamics of the Haupapa/Tasman Glacier measured at high spatial and temporal resolution, Aoraki/Mount Cook, New Zealand

Glaciers are among the clearest of signals for anthropogenic climate change and their retreat is considered symptomatic of the observed warming since the start of the 20th century from anthropogenic sources (Mann et al., 2004). New Zealand has 3,100 mountain glaciers, with those in the Southern Alps...

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Bibliographic Details
Main Author: Lui, Edmond
Format: Thesis
Language:unknown
Published: 2016
Subjects:
Online Access:https://doi.org/10.26686/wgtn.17059823.v1
https://figshare.com/articles/thesis/Ice_dynamics_of_the_Haupapa_Tasman_Glacier_measured_at_high_spatial_and_temporal_resolution_Aoraki_Mount_Cook_New_Zealand/17059823
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Summary:Glaciers are among the clearest of signals for anthropogenic climate change and their retreat is considered symptomatic of the observed warming since the start of the 20th century from anthropogenic sources (Mann et al., 2004). New Zealand has 3,100 mountain glaciers, with those in the Southern Alps experiencing losses of 34% since 1977 and a decline in volume of 51 km3 in 1994 to 41 km3 in 2010 (NIWA, 2011). The direct impact of increasing atmospheric temperatures on glaciers is well understood (Chinn, 2012) through its effects on the melt and accumulation rates (Kirkbride, 2010; Purdie, 2011; Chinn, 1997; Oerlemans, 2001). However lake calving glaciers such as the Tasman Glacier exhibit different behaviour and are suggested to be at least partially decoupled from climate forcing (Benn et al., 2007). Here, I present a temporally and spatially complete study of Haupapa/Tasman Glacier, Aoraki/Mt. Cook over three years to investigate the ice dynamics at the terminus. I used oblique photogrammetry at high resolution for data acquisition and adapted computer vision algorithms for correcting this oblique view to a real-world geometry. This technique has been rarely used (Murray et al., 2015; Messerli and Grinsted, 2015; Ahn and Box, 2010; Harrison et al., 1986 and Flotron, 1973) but owing to its cost-effectiveness and high data yields, it is becoming an increasingly powerful methodology favoured by glaciologists. During the 3 year study period, Tasman Glacier terminus retreat rate Ur was 116 ± 19 m a⁻¹ (2013-2014), 83 ± 18 m a⁻¹ (2014-2015) and 204 ± 20 (2015-2016). A strong seasonal pattern was evident in the calving events. Three major calving events occurred over the study, one occurring in the summer of 2013 and two in the summer of 2016. The latter two events are responsible for the elevated Ur in 2015-2016. These events were characterised as distinct large-magnitude calving (usually as a large tabular iceberg) which continued to drift and break up in the lake for weeks to months. Three large calving events ...