EARLY METEOROLOGICAL DATA IN SOUTHERN SPAIN, 1780-1830

F. S. RodrigoDepartment of Applied Physics, University of AlmeríaLa Cañada de San Urbano, s/n, 04120, Almería (Spain)frodrigo@ual.es

1. Introduction

The growing evidence of an anthropogenically induced climatic change and the need to compare presentday climate with that of past centuries, has boosted the search of early meteorological data from all kind of historical archives.The objective of this work is to present new data from Andalusia (southern Spain) corresponding to theperiod 1780-1830, previous to the establishment of an official meteorological service in Spain. Thisperiod coincides with the so-called ‘Dalton Minimum’, a period of minimum solar activity and intensevolcanic eruptions.Data sources are early newspapers and medical studies interested in the influence of environmentconditions on health and illness. Some examples are analyzed and their utility as data sources is studied.

2. Data sources

NR=number of rainy days; T = temperature (ºR, ºF, fraction of degree); p = pressure (English/Frenchinches, lines, fractions of line); Wd = wind direction (16-point compass); A = qualitative descriptionof atmospheric events (rainfall, fog, cloudiness, storms, etc.).Random error in the original documents and mistakes during the digitazing were checked and corrected.Independent documentary data sources (‘Salvá-Sinobas’ project database) were used to look for contemporary extreme events (indicated by in the graphs). (Wheeler, D., 1995. Early instrumental weather data from Cádiz: a study of late eighteenth and early nineteenth century records, Int. J. Climatol., 15: 801-810).

3. Rainy days in Seville, 1778-1785 (source N).

1778 1779 1780 1781 1782 1783 1784 17850

20

40

60

80

100

120

Annual rainy days in Seville

Mean value 1961-1990

Drought

Lakagígar, Iceland

1783 1784

4. Temperatures in Granada, June1796-May1797, January-February 1813, and July 1820 (sources M, EP, EC).

Comparison with monthly mean of daily maximum temperatures during 1961-1990.

0 10 20 30 40 50 6002468

10121416

Daily midday T (ºC), source EP

T(ºC) 1961-90

January 1813 February 1813

1 6 11 16 21 26 3110152025303540

Daily T(ºC), July 1820, source DC

7h 12h 17hTmax61-90 Tmin1961-90

0 6 12 18 2405

10152025303540

Monthly mean T (ºC), 12 h, 1796-1797, source M

T(ºC) 1961-90

5. Midday temperatures in Cádiz/San Fernando, 1789-1832 (sources W, A, D, P, R).Examples (December, March) of monthly means of midday T (data expressed in ºC as anomalies of the monthly mean of daily maximum temperatures during 1961-1990).

1796 1797

Lack of information on metadata (instruments, exposure conditions, etc)Sources provide very short series.Fragmentary and disperse information.Discrepancies between contemporary series.

It is difficult to construct homogeneized time series

6. Conclusions.

Annual cycles are reasonably well reproduced. Temperature data in the examples studied were slightly lower than the modern reference values. Data sources, in spite oftheir spatio-temporal dispersion, may offer interesting information on extreme events recorded in other independent documentary data sources.

A general preliminar view may be obtained, with conditions wetter and colder than during the reference period 1961-1990.

Frequent and intense volcanic eruptions along with the minimum solar activity may be the main forcing factors.

1780 1790 1800 1810 1820 1830 1840-7

-6

-5

-4

-3

-2

-1

0

1

2

3

4

December

W A D P R

Heat wave, 1803

Cold wave, 1829

1780 1790 1800 1810 1820 1830 1840-7

-6

-5

-4

-3

-2

-1

0

1

2

3

4March

W A D P R

Hailstorm, 1822

Snowfalls, 1803

Lakagígar, Iceland

= Volcanic eruptions:Lakagígar, Iceland, June 1783Etna, Italy, July 1787St Helens, USA, January 1800Tambora, Indonesia, April 1815Galunggung, Indonesia, October 1822

Cold wave, 1799

AcknowledgmentsThis work was financed by the Spanish Science Ministry (project CGL2007-65546-C03-01/CLI) and the Environment Ministry (project ‘Salvá-Sinobas’, reference number 200800050083542).

0 12 24 360

5

10

15

20

25

Monthly rainy days

Rainy days 1961-90

Intense and continuous rainfallsAutumn 1783

Flood, 28/12/1785

Flood, 21/12/1783

Intense and continuous rainfallsMarch 1785

1785