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Documentary evidence as a source of data for studying droughts in the Czech lands
Řezníčková, Ladislava ; Brázdil, Rudolf ; Kotyza, O. ; Valášek, H.
Information about past droughts may be derived from the various kinds of documentary evidence. Documentary data are particularly applicable to the pre-instrumental period but may also be used for the overlapping period with instrumental records. They are extracted from written narrative sources, weather diaries, personal and official letters, newspapers, religious records, epigraphic sources, and other sources. Direct descriptions of weather facilitate identification of meteorological droughts, while descriptions of drought impacts are used to identify agricultural and hydrological droughts. Documentary evidence enabled the creation of series of precipitation indices which classify dry months on a scale of –1 (dry), –2 (very dry), and –3 (extremely dry). In this way, it is possible to study the frequency, seasonality, severity, and impacts of drought episodes in the pre-instrumental period.
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Documentary evidence in the study of past hydrometeorological extremes in South Moravia
Chromá, Kateřina ; Brázdil, Rudolf ; Valášek, H. ; Dolák, Lukáš ; Řezníčková, Ladislava
Information about hydrological and meteorological extremes (HMEs) in the instrumental period can be extended back into pre-instrumental times using documentary evidence from a variety of data sources. Financial and economic records, particularly those related to taxation data, are among the most important such sources. For the region of South Moravia, they are held by the Moravian Land Archives in the provincial capital of Brno and in certain equivalent state district archives that contain collections of estate accounts and family archives. Exploration of these sources provides information about HMEs in terms of dates and places of occurrence, courses, and impacts. Data of this kind from South Moravia were interpreted and included in a dedicated database, bringing the number of records of past HMEs to 2,010. This contribution demonstrates the high potential of this type of data.
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Precipitation variability in the czech land since ad 1500. How strong is the signal contained within documentary sources?
Dobrovolný, Petr ; Brázdil, Rudolf ; Trnka, Miroslav ; Kotyza, O. ; Valášek, H.
Past climate may be reconstructed from a number of proxies. Some of them are “natural archives”, such as tree rings, ice cores and boreholes, most of which are sensitive to air temperature. Other valuable information can be also found in “man-made archives”. Various sources of documentary data very oft en refer not only to temperature but also to other aspects of past weather and climate, such as dry and wet periods. We use the long and homogeneous precipitation series from the recent instrumental period to calibrate precipitation indices derived from older documentary sources. Th e primary objective of this contribution is to provide a quantitative reconstruction of precipitation in the Czech Lands for the last 500 years. Calibration and verifi cation statistics are used to evaluate the strength of the signal. Reconstructed precipitation series are compared with similar Central European documentary-based reconstructions, as well as with reconstructions based on a range of natural proxies.
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Droughts in the Czech Lands during 18th century
Brázdil, Rudolf ; Řezníčková, Ladislava ; Kotyza, O. ; Valášek, H. ; Dobrovolný, Petr
Th is paper addresses dry episodes and droughts in the Czech Lands during the 18th century. It is based on various types of documentary evidence, including data describing phenomena related to drought patterns, from the occurrence of precipitation (or lack of it) to derived impacts (bad yields, water shortages, drying watercourses, etc.). Th e documentary data include various degrees of detail, but their interpretation allows work at the level of monthly resolution. Dry conditions for at least two consecutive months in a given year were considered as drought for our purposes. A total of 49 years with droughts were derived from documentary data, with the prevailing occurrence of dry months in the summer half-year (April–September: 66.0%) associated with the most severe impacts. Th is shows that probably all the droughts with two-year re-occurrence intervals were identifi ed from the documentary data available. As examples of impacts and their territorial extent, some years with severe droughts in the eastern part of the Czech Lands, Moravia, are described (1718, 1719, 1726, 1746, and 1790). Th e results obtained are an important contribution to the more broadly-oriented study of droughts in the Czech Lands during the past 500 years based on documentary and instrumental data.
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Past hydrometeorological extremes in south-western Moravia (Czech republic) derived from taxation records
Chromá, Kateřina ; Brázdil, Rudolf ; Valášek, H. ; Zahradníček, Pavel ; Dolák, L.
Historical records related to taxation at fi ve landed estates located in the south-western part of Moravia in today’s Czech Republic are employed for the study of hydrological and meteorological extremes during the 1761–1900 period. At that time, the tax system in Moravia allowed farmers to request tax relief if their crops or land were damaged by natural disaster. Th is study disclosed a total of 69 hydrometeorological events resulting in damage in the 1761–1900 period, with the highest concentration of extreme events in 1771–1799 and 1822– 1849 (together 82.6%). Of 113 extremes classifi ed, torrential rains (34.5%) and hailstorms (31.9%) were the most frequent, followed by thunderstorms, fl oods, windstorms and fl ash fl oods. June (30.4%) was the month with the highest occurrence of extreme events and July (31.0%) for classifi able extremes; in both cases their highest frequency occurred in May–August. However, the results obtained are infl uenced by uncertainties related to taxation records, such as temporal and spatial incompleteness or limitation of the vegetation period, as well as by the local occurrence of the phenomena studied, a trend demonstrated by comparison with the results of Dolák et al. (2013). Taxation records constitute a very important source of data for historical climatology and hydrology.
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