National Repository of Grey Literature 161 records found  1 - 10nextend  jump to record: Search took 0.03 seconds. 
Measuring of winter precipitation and derivation of precipitation time series using snow water equivalent at selected stations in the Sumava Mts.
Valešová, Petra ; Jeníček, Michal (advisor) ; Míka, Dominik (referee)
The measurement of winter precipitation is an important part of many scientific fields, but the same time there are many uncertainties in the measurement that can arise from inaccuracy or poor calibration of sensors, rain gauges and the influence of environmental factors. Measurement inaccuracies can be caused by the influence of wind, evaporation from heated rain gauges or clogging of the rain gauge. The aim of this work is to process data measured by a heated tipping bucket rain gauge, a classical rain gauge and snow water equivalent sensors from selected stations in the Sumava Mountains. These measured data are subsequently processed and, in case of failures, supplemented with data from other stations according to the given principles. Cumulative precipitation series for the hydrological years 2016 to 2022 are then compiled from the data thus supplemented. Key words: precipitation, snow water equivalent, snow depth, measuring of precipitation
Change in precipitation distribution as temperature rises expressed in diagnostic and prognostic data
Sokol, Zbyněk ; Řezáčová, Daniela
We summarize the main results that show how the distribution of precipitation changes with increasing temperature. Hourly rainfall totals from 97 rain gauge stations in the Czech Republic for the years 1997 to 2019 are used for the evaluation. Ground temperature, ground dew point temperature and temperature at the lifting condensation level are used to express the temperature change. The results show how an increase in temperature and a corresponding increase in saturation humidity (CC scaling) affects the distribution of precipitation in the study area. In general, the increase in precipitation as a function of observed temperature is clearly evident for the upper quantile values, but only for certain temperature intervals. It confirms the findings of other studies. In this paper, data from reanalyses performed by the ALADIN-CLIMAT/CZ model are treated similarly to the measured data.\n
Stochastic Weather Generators and Regional Climate Models: Rivals or Allies?
Dubrovský, Martin ; Štěpánek, Petr ; Meitner, Jan ; Zahradníček, Pavel
The paper demonstrates 'collaboration' between the stochastic weather generator SPAGETTA (WG) and Regional Climate Models (RCM) in analysing impacts of Climate Change (CC). In the first part of the paper, the generator is compared with the ensemble of 19 RCMs in terms of their ability to reproduce 11 spatial temperature and precipitation indices in eight European regions: the indices are based on registering days and spells exhibiting spatially significant occurrence of dry, wet, hot or cold weather, or possible combination of dryor-wet and hot-or-cold conditions. The obtained results indicate that both methodologies provide weather series of comparable quality. In the second part of the paper (which was done only for the Central Europe region), the WG parameters are modified using the RCM-based CC scenarios and the synthetic weather series representing the future climate are produced. This experiment is based on a set of CC scenarios, which consist of changes in selected combinations of following characteristics: (1) mean temperature, (2) temperature variability, (3) daily average precipitation (considering only wet days), (4) probability of wet day occurrence, (5) spatial lag-0 and lag-1day correlations of temperature and precipitation series. The synthetic series generated for each version of the CC scenario are analysed in terms the above mentioned spatial validation indices, the stress was put on effect of each of the five component of the CC scenario on individual validation indices. The results of the experiment indicate that the changes in temperature means is the main contributor to the changes in the validation obviously, except for the purely precipitation-based indices. Positive changes in the lag-0 and lag-1day correlations of both temperature and precipitation are the second most significant contributor to the changes in the validation indices.
Precipitation by PERUN
Zacharov, Petr, jr. ; Brožková, R. ; Řezáčová, Daniela
Weather reanalyses are a powerful tool for studying historical weather both at individual points and especially over an area. The detailed reanalysis produced by the PERUN project thus makes it possible to reveal various aspects of the atmosphere to a degree that we are unable to achieve with measurements. Since it is still a model approximation, it is of course necessary to detect systematic biases by verification before its use. Climate model runs, on the other hand, can uncover the future evolution of the atmosphere. Since these calculations cannot yet be verified, it is necessary to validate a historical run of the same model and subtract the revealed systematic errors from the future projections. In the PERUN project, both the historical run and two climate runs up to 2100 have been calculated. In this work, we present a basic verification and validation of the precipitation forecasts and an evaluation of the separation of precipitation into stratiform and convective precipitation and, in addition, into\nliquid and solid precipitation.
Bias correction of regional climate model outputs: statistical transformations of precipitation series from the climate model ALADIN in the project PERUN
Martínková, Marta
The outputs of regional climate models are biased. Regarding the bias correction of outputs from a climate model, the two fundamental approaches exist. First approach (e.g., Delta change method) gets the information on climate signal from comparison of the model control and future periods. Such information (change factor) is then applied to modify the observational data. Bias correction method gets the information on model bias from comparison of observational data and model outputs for the control period. The model outputs for future period are than corrected using this information on the model bias. This contribution is focused on the possibilities for bias correction of the model ALADIN (CNRM-ESM2-1) in the project PERUN and the precipitation series in daily time step for SSP5-8.5 scenario. Different statistical transformations are compared: methods based on statistical distribution, parametric transformations and non-parametric transformations (empirical quantiles method).\n
Impacts of global climate change on lichens
Šubrtová, Tereza ; Malíček, Jiří (advisor) ; Peksa, Ondřej (referee)
Lichens, also known as lichenized fungi, are primarily known as excellent indicators of environmental change. Due to climate change, lichens are increasingly being studied for their indication and prediction of individual factors of global climate change. In the first part of this work, individual abiotic factors affecting lichens on a global scale are examined, to understand these factors in all possible environments. The next part of the work focuses on Europe and addresses the history of the development and future prediction of lichen distribution under the influence of climate change. The end of the work is focused on the territory of the Czech Republic and mentions the most affected species in our area. The study of global climate change on lichens is important not only for understanding the effects of environmental changes on organisms but also for proper prioritization of nature protection leading to a halt in the decline of species and their habitats.
Compensation of Temperature Instability of the Received Signal Level of Microwave Links
Repa, Pavol ; Musil, Petr (referee) ; Bubniak, Milan (advisor)
This thesis deals with the field of microwave links. Specifically, it is concerned with compensating for the temperature instability of the received signal level of microwave links. This problem is solved according to the proposed algorithm, which can be used to suppress the temperature waveforms, and thus achieve better results in the calculation of collisions in the Telcorain software application. A compensation algorithm has been developed to compensate for microwave links with strong temperature dependence. By~compensating for these non-compliant microwave links, it was possible to reuse them in the calculation of the average rainfall intensity, and hence they were retained in~the~generation of the 2D rainfall maps. The compensation algorithm is implemented in the~Telcorain application, where the individual results of the precipitation calculation can be verified. Throughout the thesis, microwave joints from two manufacturers, each with a~different technology used, were analysed. Their comparison with each other is~the~focus of this thesis, in which the individual differences between these microwave links are published.
Research on Methods for Quantifying Attenuation due to the Wet Antenna Effect
Skoumal, Vladimír ; Dvořák, Radim (referee) ; Bubniak, Milan (advisor)
The topic is the calculation of precipitation using commercial microwave links. Since current techniques in meteorology are not perfect, this way of measurement can be a suitable complement to meteorological instruments. One of the current problems is wet antenna attenuation. This is an excess attenuation that affects the final precipitation calculation. In the first part of the thesis, microwave connections are generally described, how they look, how they are put into operation and their important parameters. Furthermore, this section contains a theoretical analysis of precipitation, various types of measurement of this quantity, and a description of the possibilities of measuring precipitation using microwave links. An important theoretical part is the description of the methods for calculating the WAA or wet antenna attenuation, where the Schleiss, Leijnse and Pastorek methods are described. Furthermore, freely usable libraries are described in the work, which contain functions for calculations of precipitation using microwave links. The last theoretical part describes the Telcorain application, which is used to calculate precipitation at this work. The second part of this work contains the changes made in the code of the Telcorain application. It also contains a comparison of WAA methods for calculating precipitation as well as variously selected sets of microwave links for different rain events and development development of own method for WAA calculation.
Possibilities of utilization of nitrogen compounds from liquid suspensions generated in waste management
Vajdíková, Tereza ; Mergl, Václav (referee) ; Kalivoda, Josef (advisor)
This thesis deals with the removal of ammoniacal nitrogen from biogas plant waste to produce a new usable product. In the theoretical part of the thesis, attention is paid to waste management from the perspective of biogas plants, the problem of nitrogen, and its removal. The thesis contains, among other things, theoretical calculations that include distribution and precipitation curves. The practical part deals with the correctness of these curves, as well as the precipitation of ammonium ions to form ammonium magnesium phosphate and stripping. The practical part includes quantitative and qualitative analyses of the individual components involved in precipitation. Nitrogen removal was performed on the model and real samples.
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.

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