Abstract
To clarify the factors contributing to surface melting, we investigated the surface energy balance at the SIGMA-A site on the northwest Greenland ice sheet from 2012 to 2019 using meteorological data observed at an automated weather station. We performed quality control prior to data analysis. Our analysis showed that the amount of surface melting increased in years with warm summers, when sensible heat transport and net shortwave radiation increased. Positive feedback between snow grain growth and near-infrared albedo reduction played an important role in the melting process. The relationship between the North Atlantic Oscillation index and surface melt flux revealed that July 2012 was an extraordinary year, characterised by a significant increase in melting caused partly by increased downward longwave radiation from the lower clouds, which suppressed net longwave cooling, and partly by the increases in sensible heat and net shortwave radiation that are generally associated with warm summers.
