National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Calculation of the spatial distribution of precipitation by various methods and evaluation of the difference in totals of rainfall in a chosen catchment
VÁVRA, Miroslav
This thesis engages various methods of calculation of the spatial distribution of precipitation and the evaluation of differences in totals of rainfall in a chosen catchment. The aim of this work was to choose suitable methods for the calculation of areal rainfall and subsequently to create those methods. Most methods were developed in the GIS program. The next objective was to explore differences in monthly precipitation from hydrological years 2006 and 2007 calculated in the catchment by chosen methods. Chosen methods for the calculation of the spatial distribution of precipitation in the catchment were: arithmetic mean, Thiessen polygons, isohyetal method and inverse distance weighting method. (IDW). As a suitable catchment was selected the catchment of the Kopaninský stream where relatively dense rainfall measurement network is installed. During the solution of this thesis the area of interest had to be extended by the area between the used rain gauges which was delimited in the GIS program. The reason for an enlargement was a fact that a decomposition of rain gauges in the catchment of the Kopaninský stream did not permit the creation of isohyetal lines in this whole catchment. During the calculation and the comparison of results of individual methods was found that results of used methods were surprisingly nearly the same. It was also stated that not even sufficient dense rain gauges network does not guarantee 100% exactness for calculating the amount of the precipitation in the selected area because of their extraordinary variability.
Methods of calculating the spatial distribution of precipitation and differences in rainfall totals in a small catchment area
VÁVRA, Miroslav
This thesis is focused on methods of calculating the spatial distribution of precipitation and differences in rainfall totals in a small catchment area. The main aim is to find methods which enable transfer of spot measurements of precipitation to spatially distributed estimation and consequently comparison of results of these methods and evaluation of their differences and accuracy. For better understanding of this problematic, precipitation and its characteristics, origin and types are described. Factors which precipitation influence are also listed further in the text. The main part of this thesis is description of methods of spatial precipitation distribution and their application in a small catchment area. Methods are listed from the most common ones (Arithmetic mean method, Thiessen polygon method, Isohyetal method) to those most recent and least applied (Hypsometric method, Inverse distance weighted method, Kriging). Thiessen polygon method and Isohyetal method are described in detail and joined by figure for better understanding. Different methods of spatial precipitation distribution calculations (Thiessen polygon method, Isohyetal method, Arithmetic mean method) were compared on one catchment area with quite surprising results. The calculated values of rainfall totals in the catchment area differed only slightly using different calculation methods. It was also stated that not even with large number of rain gages in the catchment area we aren?t able to achieve 100% calculation accuracy.

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