Application of a two-step approach for mapping ice thickness to various glacier types on Svalbard
Authors:
- Johannes Jakob Fürst,
- Fabien Gillet-Chaulet,
- Toby J Benham,
- Julian A Dowdeswell,
- Mariusz Grabiec,
- Francisco Navarro,
- Rickard Pettersson,
- Geir Moholdt,
- Christopher Nuth,
- Björn Sass,
- Kjetil Aas,
- Xavier Fettweis,
- Charlotte Lang,
- Thorsten Seehaus,
- Matthias Braun
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 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.
- Record ID
- USLbf8c1450d1584d5fb2e492f4637d83ca
- Author
- Journal series
- Cryosphere, ISSN 1994-0416, e-ISSN 1994-0424
- Issue year
- 2017
- Vol
- 11
- No
- 5
- Pages
- 2003-2032
- Publication size in sheets
- 1.50
- Keywords in English
- drainage basin; glacier; ice cap; ice thickness; interpolation; mapping method; marine environment; measurement method; reconstruction; topography; uncertainty analysis
- DOI
- DOI:10.5194/tc-11-2003-2017 Opening in a new tab
- Handle.net URL
- hdl.handle.net/20.500.12128/368 Opening in a new tab
- URL
- https://tc.copernicus.org/articles/11/2003/2017/ Opening in a new tab
- Language
- eng (en) English
- License
- File
-
- File: 1
- Application of a two-step approach for mapping ice thickness to various glacier types on Svalbard, File Grabiec_Application_of_a_two_step_Cryosphere_11_5_2017.pdf / 24 MB
- Grabiec_Application_of_a_two_step_Cryosphere_11_5_2017.pdf
- publication date: 21-08-2023
- Application of a two-step approach for mapping ice thickness to various glacier types on Svalbard, File Grabiec_Application_of_a_two_step_Cryosphere_11_5_2017.pdf / 24 MB
-
- Score (nominal)
- 45
- Score source
- BIBLIOGRAFIA DOROBKU PRACOWNIKÓW UŚ
- Publication indicators
- Citation count
- 1
- Uniform Resource Identifier
- https://opus.us.edu.pl/info/article/USLbf8c1450d1584d5fb2e492f4637d83ca/
- URN
urn:uni-kat-prod:USLbf8c1450d1584d5fb2e492f4637d83ca
* presented citation count is obtained through Internet information analysis, and it is close to the number calculated by the Publish or PerishOpening in a new tab system.