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

Outline

1. Beginnings of instrumental meteorological observations

2. Early instrumental meteorological observations - Brno 1799-1847

3. Modern instrumental meteorological observations - Brno from 1848

4. Homogenisation procedure

5. Homogenised series of Brno 1800-2007

6. Conclusions

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

Thermometer and weather angel from Otto von Guericke (Körber, 1989)

Central England temperature series since AD 1659 (Manley, 1974)

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

Observations:1752 - pressure, temperature, precipitationsince 1 January 1775 air tempe-rature and pressuresince 1 May 1804 precipitation

Josef Stepling (1716-1778)The first director of the Prague- Klementinum observatory

Prague-Klementinum

The Jesuit college of St. Clement (shortly Klementinum)

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

2 Early instrumental meteorological observations - Brno 1799-1847

Time intervals of available meteorological observations in Brno, 1800-1850

Ferdinand Knittelmayer – 1799-1812

Knittelmayer observed weather in the former Dominican monastery (used in his time by army)

- 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”)

Daily records of air pressure from Ferdinand Knittelmayer

1 – Melzer 1803-1837

2 – Brno-Tuřany 1961-1990

01020304050607080

I II III IV V VI VII VIII IX X XI XII

Sráž

ky [m

m]

1 2

Jaro

0

50

100

150

200

250

1803 1805 1807 1809 1811 1813 1815 1817 1819 1821 1823 1825 1827 1829 1831 1833 1835 1837

Léto

0

50100

150200

250

300350

400

1803 1805 1807 1809 1811 1813 1815 1817 1819 1821 1823 1825 1827 1829 1831 1833 1835 1837

Podzim

0

40

80

120

160

200

1803 1805 1807 1809 1811 1813 1815 1817 1819 1821 1823 1825 1827 1829 1831 1833 1835 1837

Zima

0

2040

6080

100

120140

160

1804 1806 1808 1810 1812 1814 1816 1818 1820 1822 1824 1826 1828 1830 1832 1834 1836 1838

Brno Praha

Rok

0

100200

300400

500

600700

800

1803 1805 1807 1809 1811 1813 1815 1817 1819 1821 1823 1825 1827 1829 1831 1833 1835 1837

Sráž

ky [m

m]

1 – Melzer 1803-1837

2 – Praha-Klementinum 1805-1837

Zacharias Melzer 1803-1837

- a regional accountant

- precipitation (original records are lost, monthly totals in Beiträge zur Hydrographie Österreichs, 1913)

Kassián Hallaschka 1813-1814

- a Piarist and teacher

- later Professor of Physics at the Prague University

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

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

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

2.1 Selected problems of early meteorological observations

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

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)]

Differences in daily means calculated from (7:00, 14:00, 21:00) and (8:00, 15:00, 22:00) – Brno-Tuřany, 1982-1998

Pressure

Temperature

Relative humidity

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?)

Qualitative visual observations (e.g. fog, thunderstorm, cloud)

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

• undervalued frequency of observed meteorological phenomena

• changes in definition or understanding of meteorological phenomena

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

-40

-35

-30

-25

-20

-15

-10

1800 1805 1810 1815 1820 1825 1830 1835 1840 1845 1850

-40

-35

-30

-25

-20

-15

-10

1800 1805 1810 1815 1820 1825 1830 1835 1840 1845 1850

-40

-35

-30

-25

-20

-15

-10

1800 1805 1810 1815 1820 1825 1830 1835 1840 1845 1850

-40

-35

-30

-25

-20

-15

-10

1800 1805 1810 1815 1820 1825 1830 1835 1840 1845 1850

970

980

990

1000

1010

1020

1030

1800 1805 1810 1815 1820 1825 1830 1835 1840 1845 1850

1 2

Dife

renc

e tla

ku v

zduc

hu [h

Pa]

1811 1837

1837 1846

1846

Tlak

vzd

uchu

[hPa

]

a

b

c

d

eExample of homogenisation of air pressure 1800-1850, March (Alexandersson test), reference stations: average for Prague-Klementinum and Vienna-Hohe Warte

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 temperature 1800-1850, April (Alexandersson test), reference station: average for Prague-Klementinum and Vienna-Hohe Warte

Air pressure Air temperature

DJF

MAM

JJA

SON

Annual1 – Brno, 2 - Vienna1 – Brno, 2 – Prague + Vienna

1800-1850

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)

3 Modern instrumental meteorological observations - Brno after 1848

a – pluviometer b – wind vanec – damp thermometerd – Fortin barometer

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

A specimen of meteorological records of Paul Olexik from January 1848

Augustinian Monastery

- 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

G. J. Mendel

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

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

- 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

Brno – Pisárky, waterwork

(Fig.: A specimen of meteorological records of Brno - Pisárky from August 1894)

Brno - Květná (Agricultural Research 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

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

4 Homogenization procedure

1 - Hospital of St. Anne

2 - Augustinian Monastery

3 - Technical University

4 - Pisárky (Waterwork)

5 - Květná (Agricultural

Research Institute)

6 - Tuřany (Airport)

1

6

25 34

Compilation of Brno climatic series from 1848

The summary of the meteorological observations in Brno from 1848 up to now

Air temperature

Air pressure

„Old“ Brno

Brno – Pisárky

Brno – Květná

Brno – Tuřany

„Old“ Brno

Brno – Pisárky

Brno – Květná

Brno – Tuřany 07, 14, 21

07, 14, 21

07, 14, 21

07, 14, 21

07, 14, 21

07, 14, 21

06,14,22 07,14,21 06,13,21

06,14,22 07,14,21 06,13,21 term

period

term

period

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

inhomogeneity

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

5 Homogenized series of Brno 1800-2007

980.0

982.0

984.0

986.0

988.0

990.0

992.0

994.0

996.0

998.0

1000.0

1800

1806

1812

1818

1824

1830

1836

1842

1848

1854

1860

1866

1872

1878

1884

1890

1896

1902

1908

1914

1920

1926

1932

1938

1944

1950

1956

1962

1968

1974

1980

1986

1992

1998

2004

Brno-Dominikanské nám. Brno-various place Brno-Staré město Brno-město

Brno-Pisárky Brno-Květná Brno-Tuřany

980.0

982.0

984.0

986.0

988.0

990.0

992.0

994.0

996.0

998.0

1000.0

1800

1806

1812

1818

1824

1830

1836

1842

1848

1854

1860

1866

1872

1878

1884

1890

1896

1902

1908

1914

1920

1926

1932

1938

1944

1950

1956

1962

1968

1974

1980

1986

1992

1998

2004

compiled Brno series compiled Brno series

inhomogeneous annual pressure series

homogeneous Brno pressure series

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

1800

1806

1812

1818

1824

1830

1836

1842

1848

1854

1860

1866

1872

1878

1884

1890

1896

1902

1908

1914

1920

1926

1932

1938

1944

1950

1956

1962

1968

1974

1980

1986

1992

1998

2004

(T°C

)

Brno-Dominkanské nám. Brno-various place Brno-Staré město Brno-město

Brno-Pisárky Brno-Květná Brno-Tuřany

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

1800

1806

1812

1818

1824

1830

1836

1842

1848

1854

1860

1866

1872

1878

1884

1890

1896

1902

1908

1914

1920

1926

1932

1938

1944

1950

1956

1962

1968

1974

1980

1986

1992

1998

2004

(T°C

)

compiled Brno series compiled Brno series

5 Homogenized series of Brno 1800-2007inhomogeneous annual temperature series

homogeneous Brno temperature series

• 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

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:

- 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