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Reconstruction of Lamb weather type series back to the eighteenth century

Type of publication Peer-reviewed
Publikationsform Original article (peer-reviewed)
Author Delaygue Gilles, Brönnimann Stefan, Jones Philip D., Blanchet Juliette, Schwander Mikhaël,
Project Reconstructing Climate Using Ensemble Kalman Fitting (REUSE)
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Original article (peer-reviewed)

Journal Climate Dynamics
Title of proceedings Climate Dynamics
DOI 10.1007/s00382-018-4506-7

Open Access

Type of Open Access Repository (Green Open Access)


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. Overall, this technique can correctly reconstruct almost 75% of the Lamb daily types, when simplified to the seven main weather types. The weather type series are described and compared to the original series for the winter season only. 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.