High resolution SPOT DEM over large areas in central and south Andes and observations on the 2018 Perito Moreno glacial lake outburst flood

Abstract

This study describes the use of multi-temporal SPOT 6 and 7 tri-stereo images for producing high resolution (3 × 3 m pixel) digital elevation models (DEM) over two large (2680 and 837 km²) mountainous and glaciated regions in the Argentinian Andes. The images were radiometrically adjusted to enhance matching over different light intensity conditions, allowing for photogrammetric reconstruction in zones of both poor texture and chromatic contrast. Independent point clouds were obtained from every image pair and contrast adjustment, and then merged into a single point cloud, which was cleaned from noisy points by an iterative filtering process. The first testing place, the Cordon de la Ramada massif, is in the Central Andes, an arid area with one of the highest density of rock glaciers in the world and some of the highest peaks of the Americas. The second is in the Parque Nacional Los Glaciares in the Southern Andes, host of the notorious Perito Moreno glacier which ends in the Lago Argentino, forming cyclical ice-dams with a consequent downstream flooding after dam-break. This work provides 1) a practical application to generate high resolution DEM from SPOT 6 and 7 tri-stereo images, 2) the first high resolution DEM over Cordon de la Ramada and Perito Moreno glacier, and 3) the March 2018 pre- and post- ice-dam break DEM for the Perito Moreno glacier, which provides the opportunity to describe this glacial lake outburst flood.