Controls on spatial variability in snow accumulation on glaciers in the Southern Alps, New Zealand; as revealed by crevasse stratigraphy

2010 ◽  
Vol 25 (1) ◽  
pp. 54-63 ◽  
Author(s):  
Heather Purdie ◽  
Brian Anderson ◽  
Wendy Lawson ◽  
Andrew Mackintosh
Keyword(s):  
New Zealand ◽  
Spatial Variability ◽  
Snow Accumulation ◽  
Southern Alps

scholarly journals Isotopic and Elemental Changes in Winter Snow Accumulation on Glaciers in the Southern Alps of New Zealand

2010 ◽  
Vol 23 (18) ◽  
pp. 4737-4749 ◽  
Author(s):  
Heather Purdie ◽  
Nancy Bertler ◽  
Andrew Mackintosh ◽  
Joel Baker ◽  
Rachael Rhodes
Keyword(s):  
New Zealand ◽  
Snow Accumulation ◽  
Southern Alps ◽  
Climate Trends ◽  
Air Masses ◽  
Winter Snow ◽  
Tasman Sea ◽  
Westerly Flow ◽  
Source Signal ◽  
Δ18o And Δd

Abstract The authors present stable water isotope and trace element data for fresh winter snow from two temperate maritime glaciers located on opposite sides of the New Zealand Southern Alps. The isotopes δ18O and δD were more depleted at the eastern Tasman Glacier site because of prevailing westerly flow and preferential rainout of heavy isotopes as air masses crossed the Alps. The deuterium excess provided some indication of moisture provenance, with the Tasman Sea contributing ∼70% of the moisture received at Franz Josef and Tasman Glaciers. This source signal was also evident in trace elements, with a stronger marine signal (Na, Mg, and Sr) associated with snow from the Tasman Sea and larger concentrations of terrestrial species (Pb, V, and Zr) in air masses from the Southern and Pacific Oceans. Although postdepositional modification of signals was detected, the results indicate that there is exciting potential to learn more about climate trends and moisture source pathways and to learn from geochemical signals contained in snow and ice in the New Zealand region.

scholarly journals Controls on Spatial and Temporal Variation in Snow Accumulation on Glaciers in the Southern Alps, New Zealand

2021 ◽  
Author(s):  
◽  
Heather Purdie
Keyword(s):  
New Zealand ◽  
Atmospheric Circulation ◽  
Southern Oscillation ◽  
Snow Accumulation ◽  
Southern Alps ◽  
Substantial Contribution ◽  
Spatial And Temporal Variation ◽  
Glacier Mass Balance ◽  
Positive Trend ◽  
Unexpected Result

<p>Mountain glaciers are already responding to climatic warming, and are expected to make a substantial contribution to sea-level rise in the coming decades. The aim of this investigation in the New Zealand Southern Alps was to improve our understanding of snow accumulation variability on mid-latitude maritime glaciers, in order to allow for better estimation of future glacier mass balance. The specific aim was to investigate snow accumulation processes at a range of spatial and temporal scales, focussing on synoptic-scale atmospheric circulation influences, moisture sources for snow accumulation and local-scale dependencies of snow accumulation in relation to topography. A range of methods were utilised including direct measurement, snow and ice core analysis, statistical analysis and modelling. Snow accumulation in the Southern Alps was found to be derived predominantly from the Tasman Sea, and deposited during low pressure troughs and fronts. Although precipitation increased with elevation, wind processes redistributed this mass. On a ~monthly timescale this redistribution caused an unexpected result, namely that wind deflation of snow on Franz Josef Glacier countered the effects of greater accumulation, and total accumulation was similar at both Franz Josef and Tasman Glaciers over this period. These processes make it challenging to simulate snow accumulation patterns by simply extrapolating snowfall over an orographic barrier from lowland climate station data. On an inter-annual basis, temperature, especially during the ablation season, had most influence on net accumulation, and warm summers served to homogenise winter variability. Consequently, atmospheric circulation patterns that affect summer temperature, for example the El Niño Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) also influence inter-annual variability in net accumulation. Together, these results highlight the dependence of maritime glaciers in the New Zealand Southern Alps on the prevailing westerly circulation. Although some uncertainty surrounds how global warming will affect atmospheric circulation and synoptic weather patterns, the results of this research indicate that New Zealand glaciers can be expected to lose significant mass in the coming decades if the current positive trend in the SAM continues, and if La Niña events (positive ENSO) become more frequent.</p>

scholarly journals Controls on Spatial and Temporal Variation in Snow Accumulation on Glaciers in the Southern Alps, New Zealand

2021 ◽  
Author(s):  
◽  
Heather Purdie
Keyword(s):  
New Zealand ◽  
Atmospheric Circulation ◽  
Southern Oscillation ◽  
Snow Accumulation ◽  
Southern Alps ◽  
Substantial Contribution ◽  
Spatial And Temporal Variation ◽  
Glacier Mass Balance ◽  
Positive Trend ◽  
Unexpected Result

<p>Mountain glaciers are already responding to climatic warming, and are expected to make a substantial contribution to sea-level rise in the coming decades. The aim of this investigation in the New Zealand Southern Alps was to improve our understanding of snow accumulation variability on mid-latitude maritime glaciers, in order to allow for better estimation of future glacier mass balance. The specific aim was to investigate snow accumulation processes at a range of spatial and temporal scales, focussing on synoptic-scale atmospheric circulation influences, moisture sources for snow accumulation and local-scale dependencies of snow accumulation in relation to topography. A range of methods were utilised including direct measurement, snow and ice core analysis, statistical analysis and modelling. Snow accumulation in the Southern Alps was found to be derived predominantly from the Tasman Sea, and deposited during low pressure troughs and fronts. Although precipitation increased with elevation, wind processes redistributed this mass. On a ~monthly timescale this redistribution caused an unexpected result, namely that wind deflation of snow on Franz Josef Glacier countered the effects of greater accumulation, and total accumulation was similar at both Franz Josef and Tasman Glaciers over this period. These processes make it challenging to simulate snow accumulation patterns by simply extrapolating snowfall over an orographic barrier from lowland climate station data. On an inter-annual basis, temperature, especially during the ablation season, had most influence on net accumulation, and warm summers served to homogenise winter variability. Consequently, atmospheric circulation patterns that affect summer temperature, for example the El Niño Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) also influence inter-annual variability in net accumulation. Together, these results highlight the dependence of maritime glaciers in the New Zealand Southern Alps on the prevailing westerly circulation. Although some uncertainty surrounds how global warming will affect atmospheric circulation and synoptic weather patterns, the results of this research indicate that New Zealand glaciers can be expected to lose significant mass in the coming decades if the current positive trend in the SAM continues, and if La Niña events (positive ENSO) become more frequent.</p>

scholarly journals Synoptic Influences on Snow Accumulation on Glaciers East and West of a Topographic Divide: Southern Alps, New Zealand

2011 ◽  
Vol 43 (1) ◽  
pp. 82-94 ◽  
Author(s):  
Heather Purdie ◽  
Andrew Mackintosh ◽  
Wendy Lawson ◽  
Brian Anderson
Keyword(s):  
New Zealand ◽  
Snow Accumulation ◽  
Southern Alps ◽  
East And West
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