The influence of NAO on the near-surface meteorology at Summit, Greenland

Summit Station, located on the high plateau of central Greenland, is currently facing climatic changes. In July 2012, Summit hit a record high temperature (3.60C) and experienced an extreme melting event. In the summer of 2010, the ICECAPS (Integrated Characterization of Energy, Clouds, Atmospheric state, and Precipitation at Summit) project deployed a suite of instruments in Greenland, allowing for the examination of meteorological patterns at Summit. In this study, the correlations that emerged from comparing the melt event of 2012 to the conditions in 2013 and 2014 were used to decode the dynamic climate of Summit, Greenland. North Atlantic Oscillation (NAO) indices from NCEP archives, Summit Station surface based meteorology data, and ceilometer data were statistically and graphically analyzed from 2012 to 2014. The NAO index, which is based upon upper-level pressure anomalies, was used to quantitatively classify the synoptic scale patterns over Greenland. Surface-based meteorology data was examined to determine the linear correlation between the NAO and surface variables such as ten and two-meter air temperatures, barometric pressure, cloud cover, and relative humidity. The ceilometer data was used to determine the percentage of sky cover over the time periods studied. This study examined the comprehensive picture of the atmospheric conditions over the Greenland Ice Sheet during the 2012-2014 periods in order to identify the connection between the large-scale circulations over the Greenland and local processes at Summit.