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The importance of the radiation balance for water retention of the landscape
Kofroňová, Jitka
As part of the radiation balance, longwave radiation is one of the factors needed to estimate potential evapotranspiration (PET). Since the longwave radiation balance is rarely measured, many computational methods have been designed. In this study, we report on the difference between the observed longwave radiation balance and modelling results obtained using the two main procedures outlined in Manuals 24 and 56 of the FAO. The performance of these equations was evaluated in the warmer months (April to October) over eight years at the Liz experimental catchment in the Bohemian Forest (Czech Republic). The coefficients of both methods were also calibrated based on local conditions. Four commonly used methods were used to calculate the PET (Penman-Monteith, Pristley and Taylor, Kimberley-Penman, Thom and Oliver). The use of default coefficient values gave errors of 40 100 mm and 0 20 mm for the seasonal PET estimates for FAO56 and FAO24, respectively (the PET was usually overestimated). Parameter calibration decreased the FAO56 error to less than 20 mm per season (FAO24 remained unaffected by the calibration). The FAO56 approach with calibrated coefficients proved to be more suitable for estimation of the longwave radiation balance.
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The influence of changes of land cover on connectivity of fluvial processes in catchment
Kofroňová, Jitka ; Langhammer, Jakub (advisor) ; Kliment, Zdeněk (referee)
The connectivity of fluvial processes or hydrological connectivity are terms often used to describe internal linkages in landscape that intensify/reduce water and sediment fluxes as well as the substances they contain. It is based on the concept of landscape connectivity defined, in particular, by fragmentation of landscape and barriers that obstruct the movement of material. While researches focusing on water erosion or runoff focus on the volume of different fluxes, connectivity reveals new information on catchment functioning as well as reactions to various types of stimuli, and thus represents a more complex phenomenon. This master thesis informs about the topic as a whole, it describes the main forms of its modelling and specific influences that have major impact on presented results. Three approaches of modelling were tested. The main concept lies in evaluation of the index of connectivity, firstly, with approach proposed by Borselli et al. (2008) and implemented in software ArcGIS and secondly, in software SedInConnect 2.0. The third approach is modelling connectivity in software LAPSUS 5.0 that belongs to landscape evolution models. Modelling in LAPSUS proved that using even this indirect method for evaluation of hydrological connectivity is a suitable approach. Selected area for modelling...
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The role of evapotranspiration in hydrological balance of small catchment
Kofroňová, Jitka ; Kliment, Zdeněk (advisor) ; Vlček, Lukáš (referee)
This bachelor thesis uses needed professional literature to explain the concept of evapotranspiration. The big part deals with chosen methods of its determination. Application part is focused on calculation of evapotranspiration with these methods and on evaluation of its intensity in area of interest as well. The thesis is aplicated on catchment of the Zbytiny stream. In this area is located a couple of measuring stations which were used for measurements of specific data needed for calculation. The purpose is determination of intensity of evapotranspiration and its importance in hydrological balance of this catchment. Powered by TCPDF (www.tcpdf.org)
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