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Homogenisation of Brno climatic series 1800-2007: Example of the use of early instrumental records

Homogenisation of Brno climatic series 1800-2007: Example of the use of early instrumental records. R. Brázdil (1) , P. Štěpánek (2), P. Zahradníček (2) , J . Macková (1) (1) Institute of Geography, Masaryk University, Brno, Czech Republic, ( brazdil@sci.muni.cz )

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Homogenisation of Brno climatic series 1800-2007: Example of the use of early instrumental records

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  1. Homogenisation of Brno climatic series 1800-2007: Example of the use of early instrumental records R. Brázdil (1), P. Štěpánek (2), P. Zahradníček (2), J. Macková (1) (1) Institute of Geography, Masaryk University, Brno, Czech Republic, (brazdil@sci.muni.cz) (2) Czech Hydrometeorological Institute, Brno, Czech Republic

  2. Outline • Beginnings of instrumental meteorological observations • Early instrumental meteorological observations - Brno 1799-1847 • Modern instrumental meteorological observations - Brno from 1848 • Homogenisation procedure • Homogenised series of Brno 1800-2007 • Conclusions

  3. 1 Beginnings of instrumental meteorological observations • Galileo Galilei (1564-1642) and his pupils – the first meteorological instruments • Rete Medicea – the first international meteorological network (10 stations) – beginning 1653-1654 – closed in 1657 Central England temperature series since AD 1659 (Manley, 1974) Thermometer and weather angel from Otto von Guericke (Körber, 1989)

  4. The first instrumental records in the Czech Lands Johann Carl Rost - Zákupy (NW Bohemia)- 21 December 1719 - 31 March 1720

  5. Prague-Klementinum The Jesuit college of St. Clement (shortly Klementinum) Josef Stepling (1716-1778) Observations: 1752 - pressure, temperature, precipitation since 1 January 1775 air tempe-rature and pressure since 1 May 1804 precipitation The first director of the Prague- Klementinum observatory

  6. First instrumental records in Moravia František Alois Mag of Magg - Telč (SW Moravia) – 7 May 1771-10 May 1775

  7. 2 Early instrumental meteorological observations - Brno 1799-1847 Time intervals of available meteorological observations in Brno, 1800-1850

  8. FerdinandKnittelmayer – 1799-1812 - a captain in pension - observations five-times a day: pressure, temperature, wind, state of the sky, meteorological phenomena - he believed for nineteen-year lunar cycle (“analoque weather forecast”) Knittelmayer observed weather in the former Dominican monastery (used in his time by army)

  9. Daily records of air pressure from Ferdinand Knittelmayer

  10. Zacharias Melzer 1803-1837 • a regional accountant • precipitation (original records are lost, monthly totals in Beiträge zur Hydrographie Österreichs, 1913) 1 – Melzer 1803-1837 2 – Brno-Tuřany 1961-1990 1 – Melzer 1803-1837 2 – Praha-Klementinum 1805-1837

  11. Kassián Hallaschka 1813-1814 • a Piarist and teacher • later Professor of Physics at the Prague University

  12. Ambros Khom 1814-1815 - a Piarist and teacher of mathematics

  13. Josef Steiner 1820-1836 - a head of the Meteorological Section of the I. R. Moravian-Silesian Economic Society Steiner’s meteorological observations were published daily in Brünner Zeitung. Observations continued without any gaps also after his death up to 31 December 1847, but an observer is unknown

  14. 2.1 Selected problems of early meteorological observations Availability of records • records are usually uknown, being not stored in the archives of the Czech Hydrometeorological Institute • they can be find randomly during the archive research • hand-written records, difficult for reading (manuscripts often written in „cursive“) • usually not clearly indicated in general archives catalogues and sometimes they are collected in funds having no relation to meteorology • old printed materials with limited access in libraries • newspapers

  15. Exact place of observations • exact specification of place of observations in the settlement is usually not indicated • most often in the home or working place of the observer • thermometers at the window (northern wall of buildings) Instruments used and their location • without information about types of instruments or needed data missing (e.g. impossibility to convert air pressure data to 0ºC) • missing description of their exact position • raw errors in measurements identified directly from the course of hourly, daily or monthly values or from comparsion with other stations

  16. Observing terms and calculations of daily means • sometimes missing term readings, only daily means (not known how they were calculated) • permanent changes in observing terms different from recent standard terms 7:00, 14:00, 21:00 h local mean time – LMT [the most extreme case: observations in the time of sunrise • (morning) and sunset (evening)] Pressure Temperature Relative humidity Differences in daily means calculated from (7:00, 14:00, 21:00) and (8:00, 15:00, 22:00) – Brno-Tuřany, 1982-1998

  17. Errors of measurements and completing of missing data • difficult identification of errors (outliers) Brno 1820 - pressure (inch) term readings published in Brünner Zeitung (an error of the observer? newspaper?) • missing data due to other activities of observers (illness, travelling, etc.) • difficult to complete missing data due to small number of contemporary stations (after homogenisation?)

  18. Qualitative visual observations (e.g. fog, thunderstorm, cloud) • undervalued frequency of observed meteorological phenomena • changes in definition or understanding of meteorological phenomena Mean monthly frequency of wind strength based on three daily observing times at Jihlava (1817-1840): 1 – calm, 2 – weak wind, 3 – medium wind, 4 – strong wind

  19. Differences in daily pressure means (hPa) between Brno and Prague-Klementinum in October 1838 and October 1840

  20. Compilation of Brno series: • air pressure (1800-1850) • air temperature (1800-1850) • relative humidity (1820-1836) • precipitation (1803-1850) • Homogenisation of Brno series: • Alexandersson test • reference stations: Prague-Klementinum, Vienna-Hohe Warte and their average Example of homogenisation of air pressure 1800-1850, March (Alexandersson test), reference stations: average for Prague-Klementinum and Vienna-Hohe Warte

  21. Example of homogenisation of air temperature 1800-1850, April (Alexandersson test), reference station: average for Prague-Klementinum and Vienna-Hohe Warte

  22. Air pressure 1800-1850 Air temperature DJF MAM JJA SON Annual 1 – Brno, 2 – Prague + Vienna 1 – Brno, 2 - Vienna

  23. Relative humidity – Brno -1820-1835: break-point in 1826, differences in mean between 1820-1826 and 1827-1836 from 8 to 10% (October to February) or from 5 to 6% (a rest of months with the expection of April)

  24. 3 Modern instrumental meteorological observations - Brno after 1848 a – pluviometer b – wind vane c – damp thermometer d – Fortin barometer

  25. Hospital of St. Anne, Pekařská Street • Observer: Dr. Paul Olexik (1800-1878), the physician • Period: 1) Hospital of St. Anne, Pekařská Street 53: from January 1848 to December 1853 • 2) Pekařská Street 100: from January 1854 to June 1878 • Observation hours: 06:00, 14:00, 22:00 h LMT • Observed elements: air pressure, air temperature, humidity, cloudiness, wind, precipitation, meteorological phenomena

  26. A specimen of meteorological records of Paul Olexik from January 1848

  27. Augustinian Monastery G. J. Mendel -Period: from July 1878 to June 1883 - Observer: Gregor Johann Mendel, the abbot od the monastery, geneticist and meteorologist - Period: from July 1883 to November 1883 -Observer: Leo Ledwina, the parson - Observation hours: 06:00, 14:00, 22:00 h LMT -Observed elements: air pressure, air temperature,humidity, cloudiness, wind, precipitation, meteorological phenomena

  28. Mendel published in 1863 annual course of meteorological elements for 1862 at Brno in comparison with mean annual variations based on 15-year observations by Paul Olexik

  29. Technical University - Period: from January 1884 to December 1889 - Observer: prof. Alfred Lorenz - Observation hours: 07:00, 14:00, 21:00 h LMT from January 1884 to May 1885 06:00, 13:00, 21:00 h LMT from June 1885 to December 1889 - Observed elements: air pressure, air temperature, humidity, cloudiness, wind, precipitation, meteorological elements Brno – Pisárky, waterwork - Period: from Juni 1890 to December 1937 (air temperature to December 1962) - Observer: technical staff of the waterwork - Observation hours: 07:00, 14:00, 21:00 h LMT - Observed elements: all meteorological elements and phenomena (Fig.: A specimen of meteorological records of Brno - Pisárky from August 1894)

  30. Brno - Květná (AgriculturalResearch Institute) - Period: from Juni 1922 to December 1971 - Observer: technical staff of the Agriculture Research Institute - Observation hours: 07:00, 14:00, 21:00 h LMT - Observed elements: all meteorological elements and phenomena

  31. Brno - Tuřany (Airport) - Period: from April 1958 up to the present - Observer: technical staff of the CHMI - Observation hours: 07:00, 14:00, 21:00 h LMT - Observed elements: all meteorological elements and phenomena

  32. 4 Homogenization procedure

  33. Compilation of Brno climatic series from 1848 1 - Hospital of St. Anne 2 - Augustinian Monastery 3 - Technical University 4 - Pisárky (Waterwork) 5 - Květná (Agricultural Research Institute) 6 - Tuřany (Airport) 3 4 2 5 1 6

  34. Air temperature term period 06,14,22 07,14,21 06,13,21 „Old“ Brno Brno – Pisárky Brno – Květná Brno – Tuřany 07, 14, 21 07, 14, 21 07, 14, 21 Air pressure term period 06,14,22 07,14,21 06,13,21 „Old“ Brno Brno – Pisárky Brno – Květná Brno – Tuřany 07, 14, 21 07, 14, 21 07, 14, 21 The summary of the meteorological observations in Brno from 1848 up to now

  35. inhomogeneity Air pressure (hPa) – differences between Brno-Pisárky (candidate series) and reference series (created from 5 stations)

  36. Air temperature (ºC) – differences between Brno-Tuřany (candidate series) and reference series (created from 5 stations)

  37. 5 Homogenized series of Brno 1800-2007 inhomogeneous annual pressure series homogeneous Brno pressure series

  38. 5 Homogenized series of Brno 1800-2007 inhomogeneous annual temperature series homogeneous Brno temperature series

  39. 6 Conclusions - early instrumental records – important source of observations for extension of existing secular meteorological series - problems with interpretation and analysis of early instrumental records: • availability of records • exact place of observations • instruments used, their location and errors of measurements • observing terms and calculations of daily means • completing of missing data • qualitative visual observations • - application of homogenisation procedure – compiled series • importance of homogeneous series for statistical analysis and study of climate change • Brno –the longest homogeneous series in the Czech Republic

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