Academic Journal
Application of a two-step approach for mapping ice thickness to various glacier types on Svalbard
| العنوان: | Application of a two-step approach for mapping ice thickness to various glacier types on Svalbard |
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| المؤلفون: | J. J. Fürst, F. Gillet-Chaulet, T. J. Benham, J. A. Dowdeswell, M. Grabiec, F. Navarro, R. Pettersson, G. Moholdt, C. Nuth, B. Sass, K. Aas, X. Fettweis, C. Lang, T. Seehaus, M. Braun |
| المصدر: | The Cryosphere, Vol 11, Pp 2003-2032 (2017) |
| بيانات النشر: | Copernicus Publications, 2017. |
| سنة النشر: | 2017 |
| المجموعة: | LCC:Environmental sciences LCC:Geology |
| مصطلحات موضوعية: | Environmental sciences, GE1-350, Geology, QE1-996.5 |
| الوصف: | 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 land-terminating glaciers as well as a 2400 km2 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. |
| نوع الوثيقة: | article |
| وصف الملف: | electronic resource |
| اللغة: | English |
| تدمد: | 1994-0416 1994-0424 |
| Relation: | https://www.the-cryosphere.net/11/2003/2017/tc-11-2003-2017.pdf; https://doaj.org/toc/1994-0416; https://doaj.org/toc/1994-0424 |
| DOI: | 10.5194/tc-11-2003-2017 |
| URL الوصول: | https://doaj.org/article/6ee4e9d1c634478d9a9c326758ca71fd |
| رقم الانضمام: | edsdoj.6ee4e9d1c634478d9a9c326758ca71fd |
| قاعدة البيانات: | Directory of Open Access Journals |
Full Text Finder | تدمد: | 19940416 19940424 |
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| DOI: | 10.5194/tc-11-2003-2017 |