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Influence of weather and climate on Ips typographus calamities in Šumava mountains
Tůma, Lukáš ; Sládek, Ivan (advisor) ; Kožnarová, Věra (referee)
European spruce bark beetle (Ips typographus) is a natural forest pest that feeds on coniferous trees, mainly on spruce. Previous studies showed that population growth of bark beetle is supported by warm and dry weather and hindered by cold and humid weather. Temperature affects development rates and influences the number of generations bark beetle may produce during one season; furthermore, it affects survival rates during the winter. Low precipitation leads to water stress of spruce trees which become more prone to bark beetle infestation. High precipitation promotes growth of mold and other natural enemies of bark beetle. The aim of the experimental part of this thesis was to analyze the relationship between population dynamics of bark beetle and weather, using data from the Šumava national park. Data did not show a significant effect of temperature and precipitation on the population growth rate of bark beetle. The growth rate was significantly correlated only with the abundance of bark beetle in the previous year. For further examination of population dynamics of bark beetle in connection with climate characteristics, it would be required to obtain better and more long-term data on bark beetle abundance; harvested bark beetle wood may be influenced by a variety of interfering (e.g....
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Precipitation variability in Prague during long-term period
Schovánková, Tereza ; Kožnarová, Věra (advisor) ; Bachanová, Soňa (referee)
Atmospheric precipitation are one of the most important meteorological element that influences both the natural environment as well as a number of human activities especially agriculture, forestry and water management. Its oversupply causing floods has also a negative impacts on ponderables and loss of life. Therefore the knowledge of the spatial distribution of precipitation and their changes in time are of great importance in the reality.
Following bachelor thesis includes a literature recherche summarizing findings of the distribution, measurement and precipitation description using precipitation characteristics. There were used data of the meteorological station Prague Karlov in the experimental part of the bachelor thesis. The attitude of the station is 260,5 m over the sea, geographic coordinates are 50 04 N and 14 25 W. The database was created using the Czech Hydrometeorological institute measurements published in the journal: Monthly review of measurement and observation of Prague Karlov observatory within the period of 1961 up to the 2010. There were used three basic precipitation characteristics to create the analysis. The characteristics are: number of days with precipitation is greater or equal to 0,1 mm,
1,0 mm and 10,0 mm. There was used a standard climatological normal as a referential characteristic which was calculated of the period 1961 up to the 1990 and supplemented by descriptive statistics parameters as everage, minimum, maximum, median, modus, standard deviation and amplitude. The results are presented in graphs and charts.
In the general evaluation of analysed period can be stated that at Prague Karlov observatory there is a trend of reduction of days with precipitation is greater or equal to 0,1 mm or 0,1 mm moreover during the whole year except the spring months when the number of days with precipitation increases. The most significant changes are in number of days with precipitation is greater or equal to 0,1 mm in January, March, July and December as well as July, September and November for precipitation is greater or equal to 1,0 mm.
It was confirmed that we are experiencing precipitation time dividing changes.
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Evaluation of air temperature in relationship for urban heat island studies
Kalousová, Jitka ; Kožnarová, Věra (advisor) ; Lenka, Lenka (referee)
The present thesis deals with another current issue, which is known as the urban heat island. Phenomenon which aries by changes in the environment i divided into two categories namely natural and anthropogenic, this two categories can work together. City and counrtyside are different, the cause is the growing urbanization of towns and changing the earth´s surface, taht can absorb solar radiation and later released into the environment. The result of this process, the warming of the atmosphere in the cities.
In the literary part describes the historical development of climate, climate as a separate element and urban heat island. Urban heat island is also distributed through energy balance, causes, impacts and possible alternatives to eliminate ist mitigation.
The main objective was to describe the available evidence and evaluate data from four different European citites (Bourges, Hamburg, Karlov and Strasbourg). Furthermore to determine through maximum and minimum monthly temperatures in the summer months, whether in those cities discovers and develops this phenomenon. Further analyze the frequency of individual synoptic situations for the period 1961-2010 and evaluated their relationship to the air temperature.
In the first hypothesis was from statistical studies demonstrated, that in summer was markked ibcidence of urban heat island, which is especially noticeable in minimum temperatures. Further analysis demonstrated that the synoptic situation, when they have their effect on the urban heat island. The second hypothesis and it´s the air temperature changes are causes by human activities, and the result is creation of urban heat island to certify based on the evaluation of the data series.
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Are there any changes in the beginning of flowering of important allergens in the Czech Republic?
Bartošová, Lenka ; Hájková, L. ; Kožnarová, V. ; Možný, M. ; Trnka, Miroslav ; Žalud, Z.
Phenological observations have a long tradition in the Czech Republic; the first phenological notes were taken in the 18th century. Within the entire phenological observation network of the Czech Hydrometeorological Institute, 45 plant species can be observed. These include perennial herbs, grass, and ground bushes growing wildly. Some observed species are among the group of so-called allergens, e.g. silver birch (Betula pendula Roth), cocksfoot (Dactylis glomerata L.), and meadow foxtail (Alopecurus pratensis L.). In this paper, we evaluated the phenological phase beginning of flowering for two of the aforementioned plants at the Mlýny, Chřibská research site (50°52’N, 14°29’E, 350 m a.s.l.). The aim was to assess which meteorological parameters influence phenological onsets as well as to analyze shifts in phenophase onset dates and temperature trends during 1959–2014. During this period, for B. pendula the average date of beginning of flowering was 28 April with a standard deviation of 10 days and for A. pratensis it was 20 May with a standard deviation of 8 days. The studied species are allergens and their timing and phenological shifting during the spring and their relationship with climate parameters may provide important information for forecasts as part of a pollen warning service.
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