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The magnitude of regional cooling across Southern Patagonia during the Antarctic Cold Reversal and Younger Dryas determined by glacier modelling

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Version 2 2023-03-09, 23:43
Version 1 2022-09-16, 03:53
thesis
posted on 2023-03-09, 23:43 authored by Ruby MuirRuby Muir

Determining the magnitude, timing and regional extent of past abrupt climate change events is crucial to resolve the spatial patterns and determine mechanism that drive rapid climate fluctuations. This thesis presents glacier model based quantitative paleotemperature reconstructions from two mountain glaciers in Southern Patagoniathat encompass the Late Glacial (c. 14.6–12.8 ka). Temperature anomalies resolved across a series of closely spaced Antarctic Cold Reversal (ACR; c. 14.5-12.9 ka) moraines were -3.0--2.6 °C at 47°S and -2.7--2.4 °C at 44°S. In both locations this was followed by either a precipitation reduction of 15-20 %, or a warming of +0.3°C from the Antarctic Cold Reversal moraines to moraines dated to the Younger Dryas (c. 12.9-11.7 ka). These anomalies show a shared, regional response across this latitude range in Patagonia, that follows the Antarctica temperature record. Further, the anomalies determined are a similar magnitude to glacier model based Antarctic Cold Reversal temperatures in New Zealand across the latitudes of 39-44 °S. This is evidence for a shared trans-Pacific climate response across the mid to high latitudes (47-39 °S) throughout the Late Glacial, that is best explained by a northward expansion of the southern westerly winds during the Antarctic Cold Reversal. These reconstructions were produced using globally available, remote sensing-based glacier datasets, and global reanalysis climate datasets.

The methodology applied presents an efficient paleoclimate reconstruction approach, which could be applied to the growing database of dated glacial moraines to produce a consistent, globally distributed, paleotemperature dataset.

History

Copyright Date

2022-09-16

Date of Award

2022-09-16

Publisher

Te Herenga Waka—Victoria University of Wellington

Rights License

Author Retains Copyright

Degree Discipline

Physical Geography

Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level

Masters

Degree Name

Master of Science

Victoria University of Wellington Unit

Antarctic Research Centre

ANZSRC Socio-Economic Outcome code

190599 Understanding climate change not elsewhere classified

ANZSRC Type Of Activity code

4 Experimental research

Victoria University of Wellington Item Type

Awarded Research Masters Thesis

Language

en_NZ

Victoria University of Wellington School

School of Geography, Environment and Earth Sciences

Advisors

Eaves, Shaun; Vargo, Lauren