Air temperature in Toruń (Poland) in the period 188 4 -1889

1. 12th EMS Annual Meeting & 9th European Conference on Applied Climatology (ECAC), Łódź, 10-14 September 2012 Rajmund Przybylak, Aleksandra Pospieszyńska Air temperature in Toruń (Poland) in the period 1884-1889 Department of Climatology, Faculty of Earth Sciences, NicolausCopernicus University, Toruń, Poland, rp11@umk.pl

2. R. Przybylak, A. Pospieszyńska,"Air temperature in Toruń (Poland) in the period 1884-1889" 12th EMS Annual Meeting & 9th European Conference on Applied Climatology (ECAC), Łódź, 10-14 September 2012 Data and measurementmethods (1884-1889) • Daily data from 1884-1889 werepublished in Annals of the Royal Prussian Meteorological Service. • Daily data from Toruń for contemporary period 2001-2010 weretaken from the Institute of Meteorology and Water Management (IMGW). • The daily data from the 19th century were quality-controlled and compared with corresponding data from the contemporary period (2001-2010). Additionally, monthly historical data were alsocompared with all available and homogenized air temperature data(1871-2010). • Air temperature measurements were conducted three times a day (at 6 a.m., 2 p.m., and 10 p.m.) using a mercurythermometerdegrees in Celsius scale. • Extreme thermometerswereconstructedby Geissler (maximum) and by Casella (minimum).

3. Source data from Toruń, Jan-April 1884 (PreussischeStatistic, KoniglichenmeteorologischenInstitut, 1884)

4. R. Przybylak, A. Pospieszyńska,"Air temperature in Toruń (Poland) in the period 1884-1889" 12th EMS Annual Meeting & 9th European Conference on Applied Climatology (ECAC), Łódź, 10-14 September 2012 Location of measurementsites in Toruń Instrumental measurements in organized networks Continuous meteorological observations in Toruń began in the second half of the nineteenth century within the Royal Prussian Meteorological network. After regaining independence (in 1918) measurements in Toruń began in 1920. Theywere performed by the National Hydro-Meteorological Institute (PIHM), and later by the Institute of Meteorology and Water Management (IMGW). Location of stations has been changing, mainly as a result of urban expansion into areas previously undeveloped. Toruń

5. Results

6. R. Przybylak, A. Pospieszyńska,"Air temperature in Toruń (Poland) in the period 1884-1889" 12th EMS Annual Meeting & 9th European Conference on Applied Climatology (ECAC), Łódź, 10-14 September 2012 Course of air temperature in Toruńin the period 1871-2010 1884-1889 – temperaturestatistics • Meanannualtemperature: 7.2°C • The warmestmonth: 17.7°C (July) • The coolestmonth: -2.6°C (January) • Absolute maximum: 34.1°C (11 June 1889) • Absolute minimum: -23.7°C (2 January 1888)

7. R. Przybylak, A. Pospieszyńska,"Air temperature in Toruń (Poland) in the period 1884-1889" 12th EMS Annual Meeting & 9th European Conference on Applied Climatology (ECAC), Łódź, 10-14 September 2012 Annual coursesof air temperaturein Toruń in periods 1884-1889, 1921-2000, 2001-2010 and theiranomalies (relative to the average from period 1871-2010) 1921-2010 1884-1889 2001-2010

8. R. Przybylak, A. Pospieszyńska,"Air temperature in Toruń (Poland) in the period 1884-1889" 12th EMS Annual Meeting & 9th European Conference on Applied Climatology (ECAC), Łódź, 10-14 September 2012 Year-to-year coursesof meanseasonal and annualair temperature in Toruń in period 1884-1889 and theiranomalies(relative to the average from period 1871-2010) Mean, minimum and maximum values of airtemperature in seasons and year in Toruń, 1884-1889

9. R. Przybylak, A. Pospieszyńska,"Air temperature in Toruń (Poland) in the period 1884-1889" 12th EMS Annual Meeting & 9th European Conference on Applied Climatology (ECAC), Łódź, 10-14 September 2012 Relative frequency of occurrence of air temperature in 2ºC intervals in seasons in Toruńin periods1884-1889, 1921-2010, and 2001-2010 DJF JJA

10. R. Przybylak, A. Pospieszyńska,"Air temperature in Toruń (Poland) in the period 1884-1889" 12th EMS Annual Meeting & 9th European Conference on Applied Climatology (ECAC), Łódź, 10-14 September 2012 Relative frequency of occurrence of air temperature in 2ºC intervals in seasons in Toruń in periods1884-1889, 1921-2010, and 2001-2010 MAM SON

11. Criteria for thermalseasons (Merecki 1914) Dailymean • winter ≤ 0oC • 0oC < early spring ≤ 5oC • 5oC < spring ≤ 15oC • summer > 15oC • 5oC < autumn ≤ 15oC • 0oC < early winter ≤ 5oC

12. R. Przybylak, A. Pospieszyńska,"Air temperature in Toruń (Poland) in the period 1884-1889" 12th EMS Annual Meeting & 9th European Conference on Applied Climatology (ECAC), Łódź, 10-14 September 2012 Thermalseasons in Toruń, 1884-2010 Dates of beginning and ending of thermalseasons in Toruń

13. Conclusions

14. R. Przybylak, A. Pospieszyńska,"Air temperature in Toruń (Poland) in the period 1884-1889" 12th EMS Annual Meeting & 9th European Conference on Applied Climatology (ECAC), Łódź, 10-14 September 2012 Conclusions • The analysed period was generally cooler than the 20th and the beginning of the 21st century. • The mean annual air temperature in the analysed period (7.2°C) was approximately 0.5°C and 1.5°C lower than the same variables in the periods of 1871-2010 and 2001-2010, respectively. • The highest temperature measured in Toruń after 1921 was 38.2°C and occurred on 11th July 1959, whereas the lowest temperature was -32.4°C, recorded on 19th January 1963. The maximum air temperature in the analysed period reached 34.1˚C on 11th June 1889, whereas the minimum temperature was -23.7°C on 2nd January 1888. • On average, the annual mean temperature was mainly influenced by winter and summer thermal conditions. The warmest month in the analysed period was July (17.7°C), which however was nearly 2°C cooler than in the contemporary period. On the other hand, January was the coolest month in both periods.

15. R. Przybylak, A. Pospieszyńska,"Air temperature in Toruń (Poland) in the period 1884-1889" 12th EMS Annual Meeting & 9th European Conference on Applied Climatology (ECAC), Łódź, 10-14 September 2012 Conclusions • In 1884-1889, the highest mean monthly day-to-day variability of air temperature was observed in winter and spring. In contrast, the lowest one was observed during summer. Although the annual cycle in variability was similar to the one observed at present, the values were greater in the historical period. • In the contemporary period of 2001-2010, mean daily air temperatures exceeding 6.0°C were more frequent than in the historical period. The most diverse distribution of frequency of air temperature calculated for 2°C intervals appeared in spring. • The duration of the winter and earlywinterreduced the most (30 and 10 days, respectively). On the otherhandduration of early spring and summerincrease for about 20 dayseach. Alsoduration of growingseasonhasincreased from 208 days (1884-1889) to 228 days (2001-2010).

16. R. Przybylak, A. Pospieszyńska,"Air temperature in Toruń (Poland) in the period 1884-1889" 12th EMS Annual Meeting & 9th European Conference on Applied Climatology (ECAC), Łódź, 10-14 September 2012 Acknowledgements • The work was done within the Polish-Swiss project entitled „Climate of northern Poland during the last 1000 years: Constraining the future with the past (CLIMPOL)” • The source data used in the dissertation entitled „Climate changesin the region of Toruń on the basis of instrumental,historical and dendrochronologicaldata” comes from the Institute of Meteorology and Water Management - National Research Institute.

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