The impact of extreme summer melt on net accumulation of an avalanche fed glacier, as determined by ground‐penetrating radar

Purdie, Heather; Rack, Wolfgang; Anderson, Brian; Kerr, Tim; Chinn, Trevor; Owens, I. F.; Linton, Matthew

doi:10.1111/geoa.12117

Cited by 15 publications

(22 citation statements)

References 33 publications

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“…We interpret this as evidence that the proposed approach may also be capable of detecting inconsistencies in the observational record, which are described by Stumm (2011), but we cannot rule out that secondary processes that are not fully accounted for might be having an effect on mass balance (e.g. Purdie and others, 2015). Importantly, the regression approach based on a predictor of annual balance does benefit from redundancy that helps to mitigate errors associated with the observations, while producing a spatially consistent map of annual balance.…”

Section: Years With Only Winter and Annual Mass-balance Measurementsmentioning

confidence: 79%

An 11-year record of mass balance of Brewster Glacier, New Zealand, determined using a geostatistical approach

et al. 2016

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ABSTRACT. Recognising the scarcity of glacier mass-balance data in the Southern Hemisphere, a massbalance measurement programme was started at Brewster Glacier in the Southern Alps of New Zealand in 2004. Evolution of the measurement regime over the 11 years of data recorded means there are differences in the spatial density of data obtained. To ensure the temporal integrity of the dataset a new geostatistical approach is developed to calculate mass balance. Spatial co-variance between elevation and snow depth allows a digital elevation model to be used in a co-kriging approach to develop a snow depth index (SDI). By capturing the observed spatial variability in snow depth, the SDI is a more reliable predictor than elevation and is used to adjust each year of measurements consistently despite variability in sampling spatial density. The SDI also resolves the spatial structure of summer balance better than elevation. Co-kriging is used again to spatially interpolate a derived mean summer balance index using SDI as a co-variate, which yields a spatial predictor for summer balance. The average glacier-wide surface winter, summer and annual balances over the period 2005-15 are 2484, −2586 and −102 mm w.e., respectively, with changes in summer balance explaining most of the variability in annual balance.

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Section: Years With Only Winter and Annual Mass-balance Measurementsmentioning

confidence: 79%

An 11-year record of mass balance of Brewster Glacier, New Zealand, determined using a geostatistical approach

et al. 2016

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“…(1 SD), which we take as the present‐day ELA at our study site. We note that the average end of summer snowline at Rolleston Glacier falls towards the lower end of this estimate, which is consistent with observations of avalanche‐controlled mass balance at this glacier (Purdie et al ., ).…”

Section: Methodsmentioning

confidence: 97%

“…We choose to use this approach as it represents the most objective method of constraining former upper ice margins where there is often little robust geomorphic evidence. We assume that all the upper catchment area contributed mass to the palaeo-glacier, based on the steep slopes and observed avalanche activity on the present-day Rolleston Glacier (Purdie et al, 2015). We use the accumulation area ratio (AAR) method to estimate the former equilibrium line altitude (ELA).…”

Section: Manual Snowline Reconstructionmentioning

confidence: 99%

Glacier‐based climate reconstructions for the last glacial–interglacial transition: Arthur's Pass, New Zealand (43°S)

Eaves

Anderson

Mackintosh

2016

J Quaternary Science

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Geological records of mountain glacier fluctuations provide useful evidence for tracing the magnitude and rate of past temperature change. In this study, we present air temperature reconstructions for the last glacial termination in New Zealand derived using snowline reconstructions and numerical glacier modelling. We target the Arthur's Pass moraines in the Otira River catchment, which have previously been dated to the Lateglacial using cosmogenic 10Be. Recalculation of these exposure ages using a locally calibrated 10Be production rate indicates that these moraines formed ca. 16–14 ka. Our glacier modelling experiments and snowline reconstructions exhibit good agreement and show that the Arthur's Pass moraines formed in a climate that was 2.2–3.5 °C colder than present. Combining our results with other, proximal glacier records shows that ice in this catchment retreated ca. 50 km from the coastal plain to the main divide during the interval 17–15 ka, in response to a temperature increase of at least ca. 3 °C. Over half of this retreat occurred after the glacier had withdrawn from an overdeepened basin. Thus, we conclude that temperature increase was the primary driver of widespread and rapid glacier retreat in New Zealand at the onset of the last glacial termination.

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“…Despite the large differences between the albedo and snowline methodologies, both aim to remotely capture the point of maximum ablation at the glacier surface and use it as a proxy for mass balance. SLA i -used as an estimate of the ELA -provides an effective measure of glacier mass balance (Rabatel et al, 2005) and should therefore be closely related toᾱ min yr (Dumont et al, 2012).…”

Section: Comparison To the Eoss Surveymentioning

confidence: 99%

“…Today, comprehensive glaciological mass balance programmes exist on Brewster Glacier (e.g. Cullen et al, 2017) and Rolleston Glacier (Purdie et al, 2015), extending back to 2004 and 2010, respectively. The size of Brewster Glacier (ca.…”

Section: Introductionmentioning

confidence: 99%

Variability in glacier albedo and links to annual mass balance for the gardens of Eden and Allah, Southern Alps, New Zealand

2020

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Abstract. The gardens of Eden and Allah (GoEA) are two of New Zealand's largest ice fields. However, their remote location and protected conservation status have limited access and complicated monitoring and research efforts. To improve our understanding of the spatial and temporal changes in mass balance of these unique ice fields, observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors are used to monitor annual minimum glacier-wide albedo (α¯yrmin) over the period 2000–2018. The α¯yrmin for 12 individual glaciers ranges between 0.42 and 0.70 and can occur as early as mid-January and as late as the end of April. The evolution of the timing of α¯yrmin indicates a shift to later in the summer over the 19-year period on 10 of the 12 glaciers. However, there is only a weak relationship between the delay in timing and the magnitude of α¯yrmin, which implies that albedo is not necessarily lower if it is delayed. The largest negative departures in α¯yrmin (lower-than-average albedo) are consistent with high snowline altitudes (SLAs) relative to the long-term average as determined from the End of Summer Snowline (EOSS) survey, which has been the benchmark for monitoring glaciers in the Southern Alps for over 40 years. While the record of α¯yrmin for Vertebrae Col 25, an index glacier of the EOSS survey and one of the GoEA glaciers, explains less than half of the variability observed in the corresponding EOSS SLA (R2=0.43, p=0.003), the relationship is stronger when compared to other GoEA glaciers. Angel Glacier has the strongest relationship with EOSS observations at Vertebrae Col 25, accounting for 69 % of its variance (p<0.001). A key advantage in using the α¯yrmin approach is that it enables variability in the response of individual glaciers to be explored, revealing that topographic setting plays a key role in addition to the regional climate signal. The observed variability in individual glacier response at the scale of the GoEA contrasts with the high consistency of responses found by the EOSS record across the Southern Alps and challenges the suggestion that New Zealand glaciers behave as a unified climatic unit. MODIS imagery acquired from the Terra and Aqua platforms also provides insights about the spatial and temporal variability in clouds. The frequency of clouds in pixels west of the Main Divide is as high as 90 % during summer months and reaches a minimum of 35 % in some locations in winter. These complex cloud interactions deserve further attention as they are likely a contributing factor in controlling the spatial and temporal variability in glacier response observed in the GoEA.

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The impact of extreme summer melt on net accumulation of an avalanche fed glacier, as determined by ground‐penetrating radar

Cited by 15 publications

References 33 publications

An 11-year record of mass balance of Brewster Glacier, New Zealand, determined using a geostatistical approach

An 11-year record of mass balance of Brewster Glacier, New Zealand, determined using a geostatistical approach

Glacier‐based climate reconstructions for the last glacial–interglacial transition: Arthur's Pass, New Zealand (43°S)

Variability in glacier albedo and links to annual mass balance for the gardens of Eden and Allah, Southern Alps, New Zealand

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