Daily Lamb weather type for the British Isles and North Atlantic Oscillation winter index over 1781-1996, supplement to: Delaygue, Gilles; Brönnimann, Stefan; Jones, Philip D; Blanchet, Juliette; Schwander, Mikhaël (2019): Reconstruction of Lamb weather type series back to the eighteenth century. Climate Dynamics, 52(9-10), 6131-6148

• Main Author: Delaygue, Gilles
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2018
• Subjects: Juliette; North Atlantic; North Atlantic oscillation
• Online Access: https://dx.doi.org/10.1594/pangaea.896308; https://doi.pangaea.de/10.1594/PANGAEA.896308

The Lamb weather type series is a subjective catalogue of daily atmospheric patterns and flow directions over the British Isles, covering the period 1861–1996. Based on synoptic maps, meteorologists have empirically classified surface pressure patterns over this area, which is a key area for the progression of Atlantic storm tracks towards Europe. We apply this classification to a set of daily pressure series from a few stations from western Europe, in order to reconstruct and to extend this daily weather type series back to 1781. We describe a statistical framework which provides, for each day, the weather types consistent enough with the observed pressure pattern, and their respective probability. Since the low frequency variability of synoptic conditions is directly related to the North Atlantic Oscillation (NAO), we derive from the weather type series an NAO index for winter. An interesting feature is a larger multidecadal variability during the nineteenth century than during the twentieth century.