A database of worldwide glacier thickness observations

Gärtner‐Roer, Isabelle; Naegeli, Kathrin; Huss, Matthias; Knecht, Thomas; Machguth, Horst; Zemp, Michael

doi:10.1016/j.gloplacha.2014.09.003

Cited by 66 publications

(58 citation statements)

References 36 publications

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“…In this respect ice volume estimates from direct ice thickness measurements are of high importance and provide valuable ground truth. Currently the global ice thickness database contains observations from ∼1,100 glaciers and ice caps (Gärtner-Roer et al, 2014). Table 2 for their names and statistics.…”

Section: Introductionmentioning

confidence: 99%

Volume Changes of Elbrus Glaciers From 1997 to 2017

et al. 2019

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This study describes the analysis of changes in area and volume of the Mt.Elbrus glacier system, Central Caucasus from 1997 to 2017. It is based on helicopter-borne ice thickness measurements, comparison of high-resolution imagery and two digital elevation models (DEMs) with 10 m resolution. More than 250 km of ground-penetrating radar (GPR) profiles of ice thickness with reliable reflections were obtained. The total volume of Mt. Elbrus glaciers was 5.03 ± 0.85 km 3 of ice in 2017. Our results show that 68% of the total ice volume is concentrated below 4,000 m a.s.l. where the average ice thickness was 44.6 ± 7.3 m, 18% of the volume lies within 4,000-4,500 m a.s.l. (thickness of 41.2 ± 7.3 m), and just 14% lies above 4,500 m a.s.l. (thickness of 29.7 ± 6.7 m). The glacier-covered area of Mt. Elbrus decreased from 125.76 ± 0.65 km 2 in 1997 to 112.20 ± 0.58 km 2 in 2017, a reduction of 10.8%. Over the same period the volume decreased by 22.8%. The mass balance of the Elbrus glaciers decreased by −0.55 ± 0.04 m w.e. a −1 from 1997 to 2017. Mass balance on west-oriented glaciers is less negative than on east-and south-oriented glaciers where mass balance is most negative. The mass balance of the east-oriented Djikiugankez glacier decreased at the fastest average rate (−0.97 ± 0.07 m w.e. a −1 ). This glacier contains 28% of the total Elbrus glacier system ice volume, most of which is concentrated below 4,000 m a.s.l. Only one small glacier on the western slope demonstrated mass gain. Our results match well with the long term direct mass balance measurements on the Garabashi glacier on Elbrus which lost 12.58 m w.e. and 12.92 ± 0.95 m w.e. between 1997 and 2017 estimated by glaciological and geodetic method, respectively. The rate of Elbrus glacier mass loss tripled in 1997-2017 compared with the 1957-1997 period.

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Section: Introductionmentioning

confidence: 99%

Volume Changes of Elbrus Glaciers From 1997 to 2017

et al. 2019

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“…Despite this importance, direct measurements of glacier ice thickness remain sparse around the world (Gaertner-Roer et al, 2014). This is because obtaining such measurements can be laborious and costly, especially for alpine glaciers with rugged topography.…”

Section: Introductionmentioning

confidence: 99%

“…Several methods that estimate ice thickness from characteristics of the surface have therefore been presented (e.g. Farinotti et al, 2009;Morlighem et al, 2011;Linsbauer et al, 2012;Brinkerhoff et al, 2016;Fürst et al, 2017) (Gaertner-Roer et al, 2014;Farinotti et al, 2017), but direct measurements remain pivotal for both the assessment of their performance and their calibration (Farinotti et al, 2017). It is still under debate, moreover, whether such approaches do indeed outperform a simple interpolation schemes when direct measurements are available.…”

Section: Introductionmentioning

confidence: 99%

The bedrock topography of Gries- and Findelengletscher

et al. 2018

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Abstract. Knowledge of the ice thickness distribution of glaciers is important for glaciological and hydrological applications. In this contribution, we present two updated bedrock topographies and ice thickness distributions for Gries-and Findelengletscher, Switzerland. The results are based on ground-penetrating radar (GPR) measurements collected in spring 2015 and already-existing data. The GPR data are analysed using ReflexW software and interpolated by using the ice thickness estimation method (ITEM). ITEM calculates the thickness distribution by using principles of ice flow dynamics and characteristics of the glacier surface. We show that using such a technique has a significance advantage compared to a direct interpolation of the measurements, especially for glacier areas that are sparsely covered by GPR data. The uncertainties deriving from both the interpretation of the GPR signal and the spatial interpolation through ITEM are quantified separately, showing that, in our case, GPR signal interpretation is a major source of uncertainty. The results show a total glacier volume of 0.28±0.06 and 1.00 ± 0.34 km 3 for Gries-and Findelengletscher, respectively, with corresponding average ice thicknesses of 56.8 ± 12.7 and 56.3 ± 19.6 m.

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“…Berthier et al, 2010;Zwally et al, 2011;Gardelle et al, 2013;Paul et al, 2015;Zwally et al, 2015;Rankl and Braun, 2016;Vijay and Braun, 2016). However, for the majority of these ice geometries, there is no information on ice thickness (Gärtner-Roer et al, 2014, 2016. Any attempt to predict the glacier demise under climatic warming and to estimate the future contribution to sea-level rise (Radić and Hock, 2011;Radić et al, 2014;Marzeion et al, 2012Marzeion et al, , 2014Huss and Hock, 2015) is limited as long as the glacier thickness is not well known.…”

Section: Introductionmentioning

confidence: 99%

“…Otherwise, SMB records are exploited to validate parametric SMB approaches (Möller et al, 2016) or more complex regional climate mod-els (Lang et al, 2015;Aas et al, 2016). For ice-thickness measurements, a standardised, open-access database has recently been launched (Gärtner-Roer et al, 2014), and its gradual growth already justified an updated release (Gärtner-Roer et al, 2016). Despite this international effort, many thickness measurements still remain unpublished.…”

Section: Introductionmentioning

confidence: 99%

Application of a two-step approach for mapping ice thickness to various glacier types on Svalbard

et al. 2017

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Abstract. The basal topography is largely unknown beneath most glaciers and ice caps, and many attempts have been made to estimate a thickness field from other more accessible information at the surface. Here, we present a two-step reconstruction approach for ice thickness that solves mass conservation over single or several connected drainage basins. The approach is applied to a variety of test geometries with abundant thickness measurements including marine-and landterminating glaciers as well as a 2400 km 2 ice cap on Svalbard. The input requirements are kept to a minimum for the first step. In this step, a geometrically controlled, non-local flux solution is converted into thickness values relying on the shallow ice approximation (SIA). In a second step, the thickness field is updated along fast-flowing glacier trunks on the basis of velocity observations. Both steps account for available thickness measurements. Each thickness field is presented together with an error-estimate map based on a formal propagation of input uncertainties. These error estimates point out that the thickness field is least constrained near ice divides or in other stagnant areas. Withholding a share of the thickness measurements, error estimates tend to overestimate mismatch values in a median sense. We also have to accept an aggregate uncertainty of at least 25 % in the reconstructed thickness field for glaciers with very sparse or no observations. For Vestfonna ice cap (VIC), a previous ice volume estimate based on the same measurement record as used here has to be corrected upward by 22 %. We also find that a 13 % area fraction of the ice cap is in fact grounded below sea level. The former 5 % estimate from a direct measurement interpolation exceeds an aggregate maximum range of 6-23 % as inferred from the error estimates here.

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A database of worldwide glacier thickness observations

Cited by 66 publications

References 36 publications

Volume Changes of Elbrus Glaciers From 1997 to 2017

Volume Changes of Elbrus Glaciers From 1997 to 2017

The bedrock topography of Gries- and Findelengletscher

Application of a two-step approach for mapping ice thickness to various glacier types on Svalbard

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