Long-term interactions between snow and the atmosphere in the Arctic

Climate assessments consistently reproduce zonal mean surface temperature warming in Arctic latitudes exceeding the global average. This Arctic Amplification was initially attributed to snow/ice albedo feedbacks, but progressing climate modeling revealed several other feedbacks playing a role as well. These include effects due to modified thermal properties of sea ice or changes in poleward energy transport and associated shifts in storm tracks, vapor and clouds. These findings are mostly based on climate modeling, but their validation by observations as well as the assessment of the relative importance of inherent processes remains difficult and is still quite controversially discussed. Based on this background, this project seeks to investigate the role of long-term snow developments and of inherent feedbacks due to e.g. changes in snow structure and snow albedo in Arctic Amplification in more detail. Albedo changes are at least partly related to the incorporation of light absorbing impurities and, thus, the chemical composition of the snow. Therefore, a second objective is related to a better understanding about chemical interactions between the atmosphere and the snow including pollutant wet/dry deposition and pollutant recycling at the snow/ice-atmosphere interface.