|
|
Automated area measurement of precipitation intensity via a network of microwave links
Bubniak, Milan ; Pospíšil, Ondřej (referee) ; Musil, Petr (advisor)
Point-to-point microwave links can be utilized as a large sensor network to measure rainfall. This work deals with the application of this procedure in practice. The first part of the thesis deals with atmospheric precipitation in general and standard methods of their measurement; and the propagation of the microwave signal and various causes of its attenuation, focusing on the attenuation caused by rain and the recommendation ITU-R P.838. This is followed by a state of the art summarization of the measurement of rainfall by microwave links. In the second part of the work, a manual procedure for calculating rainfall from microwave link data is performed, taking wet antenna attenuation into account. Then the creation of a support tool in the C# language is being described, which supply the data to the functions of the RAINLINK rainfall calculation library. Several rainfall calculations that are validated by physical rain gauges are performed. Furthermore, the own Telcorain application for rainfall calculation is created in the Python language, based on the pycomlink library. It has a graphical user interface created in PyQt. Several rainfall calculations validated by rain gauges are performed again, and the results are compared with the RAINLINK library.
|
|
|
Vliv vlhkosti půdy na hydrologickou odezvu povodí při různých srážkových úhrnech
TOMANOVÁ, Markéta
This diploma thesis deals with the Influence of soil moisture on hydrological response of a catchment to precipitation. The study was conducted on the sub-basin of Jenínský stream in the monitored vegetation period for the years 2010 - 2013. The characteris-tics such as total precipitation, flow and soil volume moisture at different depths were monitored. The first part of this thesis contains a literature study that mentions soil moisture as one of the factors influencing the hydrological response of river drainage basins to precipitation. In the practical part, the thesis deals with the evaluation of measured precipitation totals and descriptive statistical values of flow and soil moisture at a depth of 30 cm, 60 cm, 90 cm, 150 cm and 200 cm. The other section of the practical part deals with significant precipitation episodes and their impact of rain intensity on water runoff from the basin. The final objective is to evaluate the effect of soil moisture on surface runoff characteristics at different precipitation totals.
|
|
|
Automated area measurement of precipitation intensity via a network of microwave links
Bubniak, Milan ; Pospíšil, Ondřej (referee) ; Musil, Petr (advisor)
Point-to-point microwave links can be utilized as a large sensor network to measure rainfall. This work deals with the application of this procedure in practice. The first part of the thesis deals with atmospheric precipitation in general and standard methods of their measurement; and the propagation of the microwave signal and various causes of its attenuation, focusing on the attenuation caused by rain and the recommendation ITU-R P.838. This is followed by a state of the art summarization of the measurement of rainfall by microwave links. In the second part of the work, a manual procedure for calculating rainfall from microwave link data is performed, taking wet antenna attenuation into account. Then the creation of a support tool in the C# language is being described, which supply the data to the functions of the RAINLINK rainfall calculation library. Several rainfall calculations that are validated by physical rain gauges are performed. Furthermore, the own Telcorain application for rainfall calculation is created in the Python language, based on the pycomlink library. It has a graphical user interface created in PyQt. Several rainfall calculations validated by rain gauges are performed again, and the results are compared with the RAINLINK library.
|
|
|
Kinetic energy of rainfall
Pála, Jan ; Petrů, Jan (advisor) ; Gregar, Jan (referee)
Water erosion is caused by the momentum of falling raindrops and is transferred into the soil surface causing soil loss throughout the world. Rainfall kinetic energy is an important component of determining erosivity of rain with subsequent determination of the average soil loss on land and is derived from the precipitation characteristics of rain. Organised overview of the precipitation characteristics and deriving of the kinetic energy from these characteristics along with deriving methods of the kinetic energy via the rainfall intensity is done in the first part of this work in the form of literature research.
The second part of this work is focused on the comparison of the selected existing relationships for deriving kinetic energy from rainfall intensity. Kinetic energy can be expressed by form of volume specific - KEmm or time specific form - KEtime, where the model values of rainfall intensity were put into the selected formulas. Chosen KE-I relationships were compared on the basis of climate categorisation and altitude of the locations where the equations originated. Discussion and conclusion of this work assesses suitability or inapplicability of the selected equations for climate of the Czech republic.
|
|
|
Methods of Measuring Rainfall Characteristics
Holubová, Nikola ; Petrů, Jan (advisor) ; Gregar, Jan (referee)
Atmospheric precipitation is the most important meteorological phenomenon on the Earth. Therefore, more and more studies about its structure and properties have been created. Many researches describing characteristics and measurements of the precipitation have been created for more than one century. The first manual techniques, such as the method using a filter paper, which were used by the end of the 19. century, were very inaccurate. Demands on more modern techniques of measurement were rising during the 20th century. Many fully automatic devices for measuring of the precipitations characteristics were developed. Advances in technology have also had a lot of shortcomings. Some of them have been resolved, but some still exist.
The first part of this research work is focused on the precipitation and its importance, origin and extremes. The second part of the work deals with the precipitation characteristics, offering a comprehensive overview about the sizes of drops, their shape or the speed of the fall. The methods of measurement and their advantages and disadvantages are described in the third part.
|
|
|
Measurement rainfall kinetic energy using laser disdrometer
Jelínková, Petra ; Petrů, Jan (advisor) ; Hrabalíková, Michaela (referee)
The issue of water erosion is spread all over the world. It is closely related with soil aggregates breaking up and the subsequent soil nutrients loss. The total and intensity of rain are important parameters for determining the kinetic energy of rain. The measurement of rain characteristics was done in the laboratory at Czech University of Life Sciences Prague. To obtain the data rain simulator and laser disdrometer were used. With its help the intensity, volume, spectrum, even size and falling velocity of rain was found out. Overall 90 measurements were taken which describe the simulated rain characteristics in detail. Each measurement took 5 minutes. The kinetic energy was found out from the size of raindrop and its falling velocity. The average intensity of rain was 58.6 mm/h and reached KEtime 706,6 J m2/h. The droplets diameter median of all measurements was set in range of 0.375 to 0.5 mm.
|
guest ::
