Co-Registration Methods and Error Analysis for Four Decades (1979–2018) of Glacier Elevation Changes in the Southern Patagonian Icefield

VACAFLOR, PAULINA; LENZANO, MARIA GABRIELA; VICH, ALBERTO; LENZANO, LUIS

Remote Sensing

MDPI

Lugar: Basel; Año: 2022 vol. 14

The main goal of this paper is to compare two co-registration methods for geodetic massbalance (GMB) calculation in 28 glaciers making up the Upper Santa Cruz River basin, SouthernPatagonian Icefield (SPI), from 1979 to 2018. For this purpose, geospatial data have been used asprimary sources: Hexagon KH-9, ASTER, and LANDSAT optical images; SRTM digital radar elevationmodel; and ICESat elevation profiles. After the analyses, the two co-registration methods, namelyM1, based on horizontal displacements and 3D shift vectors, and M2, based on three-dimensionaltransformations, turned out to be similar. The errors in the GMB were analyzed through a k indexthat considers, among other variables, the error in elevation change by testing four interpolationmethods for filling gaps. We found that, in 63% of the cases, the relative error in elevation changecontributes 90% or more to k index. The GMB throughout our study area reported that a lossvalue of −1.44 ± 0.15 m w. e. a−1 (−3.0 Gt a−1 ) and an ice thinning median of −1.38 ± 0.11 m a−1occurred within the study period. The glaciers that showed the most negative GMB values wereUpsala, with an annual elevation change median of −2.07 ± 0.18 m w. e. a−1, and Ameghino, with −2.31 ± 0.22 m w. e. a−1.