A 44-year data set of 10-day air trajectories arriving at the crest of the Greenland Ice Sheet has been analyzed for trends in source regions and transport pathways. Using a modified 'residence time' technique in which trajectory-hours over specific regions were tallied, we observe well-defined cycles in transport from specific regions. These cycles have periods ranging from 5-15 years, and appear to be correlated with large-scale circulation indices such as the NAO. The transport time series are also compared to seasonally-resolved species within the Greenland core during the same time period