Persistent albedo reduction on southern Icelandic glaciers due to ashfall from the 2010 Eyjafjallajökull eruption

Abstract

In April and May 2010 the Icelandic volcano Eyjafjallajökull experienced an explosive eruption that led to substantial ashfall across the central-southern parts of the island. The resulting ash deposits covered Eyjafjallajökull, Mýrdalsjökull and parts of Vatnajökull ice caps. In order to quantify the influence of these deposits on albedo, we analyzed albedo evolution across Eyjafjallajökull and Mýrdalsjökull ice caps over the period 2001–2016 using the MOD10A1 and MCD43A3 data products of the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the Terra and Aqua satellites. A geostatistical model with a daily temporal resolution was used to delineate areas on the ice caps that show distinct ash cover-related albedo reductions over the post-eruption period. Results suggest that despite an overall decrease of the ash cover-related albedo reductions with time, noticeable albedo reductions persist on both, Eyjafjallajökull and Mýrdalsjökull over the entire post-eruption period. These reductions show means of 0.19 ± 0.11 and 0.17 ± 0.10, respectively, and occur most prominently during the summer seasons. Persistent albedo reductions are in agreement with and limited to areas of higher ash deposition during the volcanic eruption such as the southern parts of Eyjafjallajökull and Mýrdalsjökull ice caps. In addition, redistribution of Eyjafjallajökull ash deposited on the lowlands in southern Iceland contributed to dust storm events in the years after the eruption and caused additional albedo reductions.