A new day-to-day pressure variability index as a proxy of Icelandic storminess and complement to the North Atlantic Oscillation index 1823-2005

As unknown instrument index errors might affect the accuracy of the early parts of the long-term baseline North Atlantic Oscillation (NAO) indices, it is of interest to find alternative means for an assessment of the behavior of the NAO. Our novel day-to-day pressure variability index (dp) introduced in this paper shows interesting secular variability that is in some sense a 'measure' of the proximity of the Atlantic storm track to Iceland and thus also an independent measure of the activity of the NAO. Like the NAO indices, dp is significantly negatively (positively) correlated with temperature in western Greenland (north-west Europe). There is a significant correlation between the dp index and average wind speed at the Icelandic stations (for the time of available wind records). This correlation becomes especially prominent at multi-year time scales, but is also evident at the scale of individual months. There is no evidence of a global warming signal in this storminess proxy.