In this study, we present a two-step reconstruction approach for mapping glacier 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 an ice cap on Svalbard. In the first 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. For Vestfonna ice cap, 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 the aggregate error range of 6–23%.

Read more: Fürst, J. J., F. Gillet-Chaulet, T. J. Benham, J. A. Dowdeswell, M. Grabiec, F. Navarro, R. Pettersson, G. Moholdt, G., C. Nuth, B. Sass, K. Aas, X. Fettweis, C. Lang, T. Seehaus and M. Braun, 2017. Application of a two-step approach for mapping ice thickness to various glacier types on Svalbard, The Cryosphere, 11, 2003-2032, doi:10.5194/tc-11-2003-2017.