The longest one‐man weather chronicle (1721–1786) by Gottfried Reyger for Gdańsk, Poland as a source for improved understanding of past climate variability

Abstract

In the paper we focus on the notes of botanist and meteorologist Gottfried Reyger on the weather conditions in Gda nsk, Poland. In our estimation, this chronicle, covering the period from December 1721 to June 1786 (the longest weather chronicle recorded by a single person), is a reliable source of information with the potential to contribute to the understanding of climate variability in 18th-century Gda nsk, the significant old Hanseatic city in northern Poland. The temperature and precipitation series for the period 1721-1786 were indexed against contemporary conditions using the calculated percentages of cold, normal and warm decades. The climate in the 18th century in Gda nsk was colder than nowadays; the springs were much cooler, as were the winters, while the summers were warmer. A few relatively cold periods and several warm periods were identified. The first half of the analysed period was very humid, whereas the second was quite dry. The reconstructed indexed data series were compared to annual and seasonal mean values of air temperature and precipitation derived from regular instrumental observations made in Gda nsk since 1739. The linear regression method was applied to calibrate the reconstructed index series against anomalies from the 1961-1990 average. The correlation coefficient, standard error of estimate and the root-mean-square error statistics were used to diagnose the quality of calibration and verification. The highest correlation between the temperature indices and the observational series was found for winter. The reconstructed series for precipitation has a smaller variability than in reality. The reconstructed values for the years prior to 1739 indicate cold years for 1725-1732 and a wet period in the 1730s.

Droughts in the area of Poland in recent centuries in the light of multi-proxy data

“…Sometimes they were prepared by scholars, such as professors Marcin Biem (ca. 1470-1540) and Michał of Wiślica (1499-1575) of the Jagiellonian University, who conducted such observations in Kraków from 1499 to 1531 and from 1534 to 1551 (Limanówka, 2001), or townsmen with scientific ambitions such as Gottfried Reyger (1704Reyger ( -1788, who began his observations in Gdańsk in 1721 as a 17-year-old man and continued them later, among others as a member of the Naturforschende Gesellschaft in Gdańsk until 1786 (Filipiak et al, 2019). Sometimes daily observations were conducted by amateurs; the best examples of which are the records of the Polish nobleman from the eastern territories of the Polish-Lithuanian Commonwealth, Jan Antoni Chrapowicki, which were conducted for the years 1656-1685 (Nowosad et al, 2007).…”

“…His notes after 1783 (Hanov's death) were more accurate. Despite the lack of measured values of precipitation, detailed data on the monthly number of rainfall and snowfall were presented (for more details including the reconstruction of the air temperature and precipitation series since 1721; see Filipiak et al, 2019). Some sources suggest an even earlier date for the beginning of Reyger's instrumental observations (Hellmann, 1883, after Rojecki, 1965.…”

“…were described recently in many publications (e.g. Wilhite and Glantz, 1985;Tate and Gustard, 2000;Herweijer et al, 2007;Mishra and Singh, 2010;Dai, 2011a;Brázdil et al, 2013Brázdil et al, , 2018IPCC, 2014;Fragoso et al, 2018;White et al, 2018), and therefore a brief overview is omitted here.…”

“…Therefore, in recent decades quite a lot of drought reconstructions encompassing almost the entire millennium, or the shorter historical pre-industrial period, were constructed for different greater or smaller regions (e.g. Inglot, 1968;Piervitali and Colacino, 2001;Cook et al, 2004Cook et al, , 2010Cook et al, , 2015Herweijer et al, 2007;Pfister et al, 2006;Brewer et al, 2007;Domínguez-Castro et al, 2008Woodhouse et al, 2010;Brázdil et al, 2013Brázdil et al, , 2016Brázdil et al, , 2018 (see references herein); Dobrovolný et al, 2015;Fragoso et al, 2018;Hanel et al, 2018).…”

The climate in south-east Moravia, Czech Republic, 1803–1830, based on daily weather records kept by the Reverend Šimon Hausner

“…Although weather diaries occur nearly all over the world (e.g. see Glaser et al, 1991;Druckenbrod et al, 2003;Hirano and Mikami, 2008;Mikami, 2008;Zhang et al, 2013;Adamson and Nash, 2014;Lorrey and Chappell, 2016), Europe is a particularly rich region for them, spanning a period of almost 8 centuries. The first known daily weather records, for 1269-1270, appeared in England among a volume of papers by Roger Bacon (Long, 1974), followed by observations made by the Reverend William Merle in Lincolnshire from the years 1337 to 1344 (Lawrence, 1972).…”