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

Paulina Vacaflor,Maria Gabriela Lenzano,Luis Lenzano,Alberto Vich

doi:10.3390/rs14040820

Abstract

The main goal of this paper is to compare two co-registration methods for geodetic mass balance (GMB) calculation in 28 glaciers making up the Upper Santa Cruz River basin, Southern Patagonian Icefield (SPI), from 1979 to 2018. For this purpose, geospatial data have been used as primary sources: Hexagon KH-9, ASTER, and LANDSAT optical images; SRTM digital radar elevation model; and ICESat elevation profiles. After the analyses, the two co-registration methods, namely M1, based on horizontal displacements and 3D shift vectors, and M2, based on three-dimensional transformations, turned out to be similar. The errors in the GMB were analyzed through a k index that considers, among other variables, the error in elevation change by testing four interpolation methods for filling gaps. We found that, in 63% of the cases, the relative error in elevation change contributes 90% or more to k index. The GMB throughout our study area reported that a loss value 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−1 occurred within the study period. The glaciers that showed the most negative GMB values were Upsala, 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.

Highlights

Studies of mass balance and ice sheet volume changes are relevant in the context of global warming and the consequent rise in mean sea level [1]
Starting from the four possible combinations of the four data sources available, co-registration residual was calculated based on the scheme of
It should be noted that the slopes of the terrain where areas were hit by the Ice Cloud and Land Elevation Satellite (ICESat) sensor resulted in

Summary

Introduction

Studies of mass balance and ice sheet volume changes are relevant in the context of global warming and the consequent rise in mean sea level [1]. Remote sensing provides effective tools, and has been widely used over the last decades to extend and improve analysis at a regional and at a global scale. This is due to the fact that systems based on satellite missions continue improving imaging performance, including better spatial and spectral resolution [5]. Satellite-based data have been an excellent choice for analyzing glaciers in inaccessible areas, whereas in situ measurements present challenges in terms of logistics and the ensuing high economic cost and can be Remote Sens.

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