Area changes of glaciers on active volcanoes in Latin America between 1986 and 2015 observed from multi-temporal satellite imagery

Abstract

Glaciers on active volcanoes are subject to changes in both climate fluctuations and volcanic activity. Whereas many studies analysed changes on individual volcanoes, this study presents for the first time a comparison of glacier changes on active volcanoes on a continental scale. Glacier areas were mapped for 59 volcanoes across Latin America around 1986, 1999 and 2015 using a semi-automated band ratio method combined with manual editing using satellite images from Landsat 4/5/7/8 and Sentinel-2. Area changes were compared with the Smithsonian volcano database to analyse possible glacier-volcano interactions. Over the full period, the mapped area changed from 1399.3 ± 80 km2 to 1016.1 ± 34 km2 (-383.2 km2) or -27.4% (-0.92% a-1) in relative terms. Small glaciers, especially in tropical regions lost more of their area compared to large and extra-tropical glaciers. Interestingly, 46 out of 59 analysed glaciers (78%) showed a decelerating shrinkage rate in the second period (-1.20% a-1 before 1999 and -0.70% a-1 after 1999). We found a slightly higher (but statistically not significant) area loss rate (-1.03% a-1) for glaciers on volcanoes with eruptions than without (-0.86% a-1).