Greenland Blocking Index 1851–2015: a regional climate change signal

We present an extended monthly and seasonal Greenland Blocking Index ( GBI ) from January 1851 to December 2015, which more than doubles the length of the existing published GBI series. We achieve this by homogenizing the Twentieth Century Reanalysis version 2c‐based GBI and splicing it with the NCEP / NCAR Reanalysis‐based GBI . For the whole time period, there are significant decreases in GBI in autumn, October and November, and no significant...