Reconstruction of strong winds in Gdansk, Poland, in the 18th century

In the paper, we focused on the possibility of reconstructing information about occurrence of strong and very strong, potentially high-impact, winds in the 18th century. The analysis was dedicated to the city of Gdansk, for which there are massive sources of various historical data - a long series of instrumental data and detailed weather notes. Among instrumental data, sub-daily weather data on wind force and sea level pressure from the period 1739-1772 were used; they were measured from two to four times a day, depending on the year, by Michael Christian Hanov, a pioneer of regular meteorological instrumental measurements in Gdansk. He has developed a special classification of wind force, dedicated to the city's conditions. One of our tasks was a translation of Hanovs classes of wind force into Bft scale. Instrumental data were combined with a weather notes made by the same observer. We compared the above mentioned information with detailed weather chronicles published by Gottfried Reyger (Filipiak et al. 2018). The monthly number of strong winds classified according to Brazdil et al. 2004 as: fresh and strong breeze (5-7Bft), gale (8-9Bft) and storm (10Bft) was reconstructed. The results of analyzes based on various data sources indicate the differentiated monthly number of strong winds, depending on the source used. The further actions towards the elimination of some inconsistencies were taken. The frequency of occurrence of strong winds in the 18th century in Gdansk was further compared with contemporary results taken at synoptic station Gdansk Northern Harbour from the period 19872012.The work was done within a NCN project entitled The occurrence of extreme weather, climate and water events in Poland from the 11th to 18th centuries in the light of multiproxy data, supported by the National Science Centre, Poland, project No. 2020/37/B/ST10/00710.References:Brzdil R, Dobrovoln P., tekl J., Kotyza O., Valek H, Je J., 2004, History of weather and climate in the Czech Lands VI: Strong winds, Masaryk University, Brno.Filipiak J., Przybylak R., Oliski P., 2018. The longest one-man weather chronicle (17211786) by Gottfried Reyger for Gdask, Poland as a source for improved understanding of past climate variability. International Journal of Climatology, 39, 2, 828-842, doi: 10.1002/joc.5845.