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The change of annual and seasonal precipitation totals in the Czech Republic during 1961-2012
Střeštík, Jaroslav ; Rožnovský, J. ; Štěpánek, P. ; Zahradníček, P.
Using the monthly values of precipitation totals at 267 stations in the Czech Republic a longterm change has been estimated at each station for the last 50 years. Annual totals for the whole country display a slight increase, however, supplemented by a much stronger fluctuations from year to year. Long-term changes in annual totals at different stations and in different regions are different. In southern and western Bohemia precipitation totals increased more, in Elbe lowlands and in a large part of the Moravia, rather a small decrease in rainfall has been observed. Long-term changes depend only slightly on the total rainfall at the respective station or in the region. Summer precipitation totals increased more than annual averages, while spring precipitation totals decreased, at other times seasons the change is negligible. At the same time, the annual variation changes slightly: maximum precipitation has shifted from June to July and August.
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Character of precipitation during the last 200 years in Prague Klementinum and their impact on water management in the landscape
Střeštík, Jaroslav
The course of the annual precipitation displays no change over 200 years, only a very slow decline during the 20th century, particularly in its second half. The same, just a little stronger trend holds true for the number of days in each year with abundant precipitation and for percentage of annual precipitation in these days. Therefore, more and more water falls during weak rains instead of the richer ones, which is not favorable for agriculture, because more water evaporates shortly after the rain. In the same period, water flows in major rivers increase, or very little decrease, although precipitation totals are falling more rapidly. Therefore, the proportion of water flowing into the sea is increasing and the proportion remaining in the landscape decreases. All these factors contribute to an intermittent water shortages and an increasing risk of drought occurrence.
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Where the centre of Bohemia, Moravia, the Czech Republic and Europe is located
Střeštík, Jaroslav
The centre of any territorial unit, as e.g. Bohemia, Czech Republic, Europe etc., is undoubtedly an attraction for the town or village where this point is located. This fact contributes surely to the significance of the locality and perhaps it attracts more visitors. This is the reason why there are more localities considered as the centre of the territorial unit. In this contribution, some most significant centres are presented. The method how to determine the centre of a selected territory as the centre of gravity is described. Using this method the positions of centres of Bohemia, Moravia, the Czech Republic and Europe have been calculated and compared with other mentioned results.
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The increase of the air temperatures observed in different European localities during 1951-2010
Střeštík, Jaroslav
Uninterrupted series of annual mean temperatures from 72 European observatories have been processed. The temperature at these stations increased in general more than global temperature, but with considerable fluctuations. The increase at the individual stations is very different. It depends very slightly on the geographic longitude. Stations where lower temperature increase has been observed are located mainly at the Atlantic coast, those with higher increase being mainly in inland. There are, however, many exceptions from this rule, but the gross character of the distribution of stations with different temperature increase seems to be clear.
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Prediction of solar activity in the 24th and 25th cycles
Střeštík, Jaroslav ; Mikulecký, M.
In the half of nineties we prepared a prediction of solar activity in cycles No 23 to 26. For this prediction we used the data from 1500-1995 representing 10 significant period lengths with lowest p-values. Using the superposition of these sine waves the data of 1500-1995 were excellently fitted. The prediction for 1996-2040 was constructed as an extrapolatlon of this course. We predicted that cycles No 23 and 24 wtll be longer and the value of sunspot numbers in the maximum will be lower than that in the cycle No 22. These predictions have been so far roughly fulfilled, except only the maximum of the 23rd cycle appeared in reality a little earlier. This is why the descending part of the 23rd cycle observations found itself closely under the 957o tolerance corridor of our prediction. Using now the data since 1500 till 2010 and the same prediction method we prepared anew prediction for the cycles No 24 and 25. Both cycles should be also longer, similarly as the cycle No23 in our first predlction as well as in the reality. Values of sunspot numbers in maxima should be even lower.
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A completion of the catalog of polar aurorae observed in lower latitudes in 1001-1779
Střeštík, Jaroslav
In 1985 Křivský and Pejml published a catalog of polar aurorae observed in 1001-1900 in latitude lower than 55°N. In 1996 Křivský published a supplement to this catalog. This common catalog collects all data concerning the aurorae published earlier and it was in its time the most complete one. In 2004 appeared till now unknown data about polar aurorae observed in Korea in 1001-1779, These dta are, only with a few exceptions, not included in the catalog of Křivský, and vice versa. here the comprehensive catalog is presented, containing the Křivský's data s well as those from Korea. Further some regularities in the occcurrence of aurorae are presented using the comprehensive catalog. The distribution of aurorae in time agrees well with the reconstructed series of sunspot numbers and displays similar periodicities, especially the long-term ones.
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The temperature and precipitation course in Prague-Karlov, 1961-2010
Střeštík, Jaroslav
The course of temperatures and precipitation in Prague over the last 50 years is presented and compared with scenarios of the further development of the climate. The temperature increased significantly and this increase is more rapid than that of the global temperature. Precipitation totals display only very small decrease over the last 50 years. However, precipitation totals in spring decreased more than the annual sums and a remarkable decrease of days with heavy rainfall takes place. These facts contribute to the observed decrease of the amount of moisture in nature and to the increased occurrence of droughts. There is no indication that all these observed trends could be different in future.
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The progress of wheat prices in France and in Germany between 1531 and 1785
Střeštík, Jaroslav ; Mikulecký, M. ; Mikulecký, L.
Mean annual wheat prices in Paris and in Cologne during the 16th – 18th century display a considerable similarity, which may be expected due to the small geographical distance. In the long-term scale the prices increase, later the increase becomes slower, and this course is similar in both countries. This variation is supplemented by short-time fluctuations, again similar in both countries. In the spectra of these time series a significant peak appears in the periods near 130 and 60 years, further ones near 35 and between 14-15 years, the latter being more apparent in data from Paris. The period of solar cycle (11 years) is not significant here. Correlation with mean annual air temperatures and mean annual sunspot numbers is negative, but only a little above the limit of significance (it moves between 0.14 and 0.22). In the long-term change long-term variations of mean annual air temperatures and solar activity, valid for both countries, reflect themselves. After subtraction of the parabolic trend these correlations become lower, on the other hand, correlations with precipitation totals are more distinct. All correlations are a little higher in Germany than in France.
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Possible periodicities in occurrence of wars in Europe during the last 500 years
Střeštík, Jaroslav ; Mikulecký, M.
The occurrence of wars and their regularities are always the subject of investigation for historians. During centuries one can find some relatively quiet periods as well as periods of frequent war conflicts. For a quantitative research special indices have been constructed some time ago, which are done for each year starting 1495 till 1975. In this series some significant periodicities can be found. The most significant appears around 55 years, further ones around 131, 78, and 35 years, and also some periods less significant. No one of them corresponds to significant periods occurring in most heliogeophysical quantities; only for some less significant a similarity can be found. Therefore the correlation with solar activity as well as with mean annual air temperatures is low, though not to be neglected. The similarity is higher for long-term variations than for shortterm fluctuation. During the long-term maximum of solar activity and long-term maximum of air temperatures, which occurs usually simultaneously, a quieter period may be expected.
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The change of mean air temperatures i the town and outside the town during the last 65 years
Střeštík, Jaroslav
The climate in the town differs from that in the nearest surroundings in many respects: in the town higher air temperature. lower air humidity, much higher air pollution et. takes place. The town can be considered as an island with a different environment. Due to the increase of towns all mentioned differences between the town and its surroundings increase too. In this contribution the change of mean annual, and seasonal air temperature in the Prgue center (Klementinum) and on its boundary (airport Ruzyně) during 1946-2009, partly on airports Tuřany and Mošnov during 1951-2009, will be presented. Mean air temperatures on all stations display, besides a considerable fluctuation, a stable increase given by the global warming.
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