The main objective of this study is to assess the effect of hysteresis of soil hydraulic properties on model predictions of soil water movement in a variably saturated soil. The model predictions are generated by the S1D model, which is based on numerical solution of one-dimensional Richards’ equation. The analysis is made for a loamy sand soil located in a small headwater catchment. The model is used to simulate the development of soil water pressure during three successive vegetation seasons. Three major simulation scenarios are formulated: the first scenario assumes no hysteresis in soil hydraulic properties, the second scenario involves a predefined hypothetical hysteresis, while the third scenario is based on optimized hysteresis, determined through the inverse modeling procedure. The analysis of the simulation results suggests that, in our case, ignoring hysteresis does not lead to any significant deviation of the model predictions from the observed soil water system responses. and Možnosti efektivně matematicky modelovat proudění vody v přirozených půdních formacích omezuje komplikovanost určení půdních hydraulických charakteristik, a to nejen s ohledem na jejich prostorovou a časovou variabilitu, ale také hysterezi. Příspěvek je zaměřen na testování vlivu hystereze na výsledky simulací proudění půdní vody v podmínkách malého horského povodí. Numerický model S1D, řešící Richardsovu rovnici v jednorozměrném tvaru, byl použit k výpočtu sezónního vývoje tlaku půdní vody. V simulacích byla alternativně uvažována hystereze retenční křivky. Odchylky mezi odezvami modelu a měřeními byly minimalizovány optimalizací scaling faktorů. Rozsáhlý srovnávací soubor uskutečněných optimalizací umožnil posoudit rozdíly modelové odezvy dvou hysterezních a jedné nehysterezní varianty a kvantifikovat dopad zanedbání hystereze na přesnost předpovědi modelu. Neuvažování hystereze v našem případě nezhoršuje schopnost modelu popsat změny půdní vlhkosti.
The goal of this study was to evaluate the effect of products from a municipal wastewater treatment plant on the H2O and CO2 effluxes from two soils. The net H2O and CO2 effluxes were measured at the surface of nine beds with two different soils (Cambisol and Arenosol) and two crops (maize or vegetables). Soils in some beds were amended with stabilized sewage sludge (bed with Cambisol and maize) or composted sewage sludge (two beds with Cambisol and both crops) or were irrigated with treated wastewater (two beds with Cambisol and both crops, and one bed with Arenosol and vegetable). Remaining beds were irrigated with tap water (two beds with Cambisol and both crops, and one bed with Arenosol and vegetable). While stabilized and composted sewage sludge positively affected the CO2 emission, the effect of treated wastewater was not confirmed. Different treatments had negligible effect on the water efflux, which was mainly affected by the plant canopy that influence the temperature of the soil surface. Statistical analyses showed that trends of the CO2 efflux with respect to various scenarios measured on different days changed during the season. No significant correlations were found between the average H2O and CO2 effluxes and measured soil properties.
We cannot definitely determine precise boundaries of application of vague terms like ''tall''. Since it is only a height of a person that determines whether that person is tall or not, we can count ''tall'' as an example of a linear vague term. That means that all objects in a range of significance of ''tall'' can be linearly ordered. Linear vague terms can be used to formulate three basic versions of the sorites paradox – the conditional sorites, the mathematical induction sorites, and the line-drawing sorites. In this paper I would like to explore a possibility of formulating sorites paradoxes with so called multi-dimensional and combinatory vague terms – terms for which it is impossible to create a linear ordering of all objects in their range of significance. Therefore, I will show which adjustments must be made and which simplifications we must accede to in order to formulate any version of the sorites paradox with multi-dimensional or combinatory vague terms. I will also show that only the conditional version of the sorites paradox can be construed with all three kinds of vague terms., Nemůžeme rozhodně určit přesné hranice aplikace neurčitých termínů jako ,,vysoký''. Jelikož je to pouze výška osoby, která určuje, zda je tato osoba vysoká nebo ne, můžeme jako příklad lineárního neurčitého termínu počítat ,,vysoký''. To znamená, že všechny objekty v rozsahu významu ,,vysokého'' mohou být lineárně uspořádány. Lineární neurčité termíny mohou být použity pro formulaci tří základních verzí paradoxů soritů - podmíněných soritů, matematických indukčních soritů a soritů pro kreslení čar. V této práci bych chtěl prozkoumat možnost formulování paradoxů soritů s takzvanými vícerozměrnými a kombinatorickými neurčitými termíny - termíny, pro které není možné vytvořit lineární uspořádání všech objektů v rozsahu jejich významu. Proto, Ukážu, jaké úpravy je třeba provést a jaká zjednodušení musíme přistoupit, abychom mohli formulovat jakoukoli verzi paradoxů soritů s vícerozměrnými nebo kombinatorickými neurčitými termíny. Ukážu také, že pouze podmíněnou verzi paradoxu soritů lze chápat se všemi třemi druhy neurčitých termínů., and Jan Štěpánek
Much recent neuroscientific work, and in particular the programme initiated by Benjamin Libet, seeks to show ''the causal closure of the physical''-that mental events never cause physical events, and in particular that our intentions never cause brain events and thereby our intentional bodily actions. But no one is justified in believing any scientific theory unless they are justified in believing that it successfully predicts certain events. Someone is justified in believing that certain events predicted by some theory did occur, if they apparently remember having perceived these events or if some other scientist apparently testifies that they have perceived these events. But we believe our apparent memories of our past perceptions of events because we believe that perceiving those events has caused brain events which have caused our present apparent memories of them; and we believe the apparent testimony of others because we believe that their intentions to testify have caused brain events in them which in turn have caused the words of their testimony to come out of their mouths. So someone could only justifiably believe the theory that mental events never cause physical events if they believe that either their past perceptions or the intentions of other scientists to tell them what they perceived, both of which are kinds of mental events, have caused brain events, which are physical events. So that theory is self-defeating; no one could ever be justified in believing it, or more generally be justified in believing the theory of the causal closure of the physical., Hodně nedávná neurovědní práce, a zejména program iniciovaný Benjaminem Libetem, se snaží ukázat ,,kauzální uzavření fyzického'' - to, že duševní události nikdy nezpůsobují fyzické události, a zejména to, že naše záměry nikdy nezpůsobují mozkové příhody a tím naše úmyslné tělesné akcí. Nikdo však není oprávněn věřit žádné vědecké teorii, pokud nejsou oprávněni věřit, že úspěšně předpovídá určité události. Někdo je oprávněn věřit, že určité události předvídané nějakou teorií se vyskytly, pokud si zřejmě pamatují, že tyto události vnímaly, nebo pokud nějaký jiný vědec zřejmě svědčí o tom, že tyto události vnímaly. Ale věříme, že naše zjevné vzpomínky na naše minulé vnímání událostí, protože jsme přesvědčeni, že vnímání těchto událostí způsobilo události mozku, které způsobily naše současné zjevné vzpomínky na ně; a věříme, že zjevné svědectví druhých, protože jsme přesvědčeni, že jejich záměry svědčit způsobily v nich mozkové události, které zase způsobily, že slova jejich svědectví vyšla z úst. Tak někdo mohl jen oprávněně věřit teorii, že duševní události nikdy nezpůsobí fyzické události, pokud se domnívají, že buď jejich minulé vnímání, nebo záměry jiných vědců, jim řekly, co vnímají, což jsou oba druhy duševních událostí, které způsobily mozkové příhody, fyzické události. Takže tato teorie je samo-porážející; nikdo nemohl být ospravedlněn, když tomu věřil,nebo obecněji být oprávněn věřit teorii kauzálního uzavření fyzické., and Richard Swinburne
It was shown that the use of biochar provides many benefits to agriculture by improving the whole complex of soil properties, including soil structure. However, the diverse range of biochar effects depends on its physicochemical properties, its application rates, soil initial properties etc. The impacts of biochar, mainly its reapplication to soils and its interaction with nitrogen in relation to water-stable aggregates (WSA) did not receive much attention to date. The aims of the study were: (1) to evaluate the effect of initial application (in spring 2014) and reapplication (in spring 2018) of different biochar rates (B0, B10 and B20 t ha–1) as well as application of biochar with N-fertilizer (40 to 240 kg N ha–1 depending on the requirement of the cultivated crop) on the content of WSA as one of the most important indicators of soil structure quality, (2) to assess the interrelationships between the contents of soil organic matter (SOM) and WSA. The study was conducted in 2017–2019 as part of the field experiment with biochar on Haplic Luvisol at the experimental station of SUA in Nitra, Slovakia. Results showed that initial application as well as reapplication of biochar improved soil structure. The most favorable changes in soil structure were found in N0B20B treatment (with biochar reapplication) at which a significantly higher content of water-stable macro-aggregates (WSAma) (+15%) as well as content of WSAma size fractions of > 5 mm, 5–3 mm, 3–2 mm and 2–1 mm (+72%, +65%, +57% and +64%, respectively) was observed compared to the control. An increase in SOM content, due to both, initial biochar application and its reapplication, significantly supported the stability of soil aggregates, while organic matter including humic substances composition did not.
One of the basic questions related to the safety of dikes and river levees is the size of the freeboard. One of the important parameters for freeboard design is the height of waves and wave run-up on levee slopes. Routine and standardised calculations of wave run-up deal with the freeboards of dams where wind waves originate on the still water of the reservoir. In the case of running water in streams (thereinafter only ''currents'') the effect of wave and current interaction on wave run-up is usually not taken into account due to the lack of reliable knowledge regarding the phenomenon. In the Czech Republic this question is topical in the case of large rivers such as the Elbe, the Vltava and the Morava. Within the framework of the projects Hydralab III and NAZV QI 92A139, hydraulic research and further analysis focused on wave run-up as a result of the combination of current and wind wave parameters were performed. The laboratory research was carried out in a hydraulic flume with a wavemaker on the right bank and a levee with a slope of 1:3 installed on the left bank opposite the wavemaker. Waves were generated both perpendicular and oblique to the levee axis; the angle of oblique wave attack varied within the range of ± 30°. The aim of this paper is to compare the results of the mentioned research with recommendations mentioned in the Czech National Standard CSN 75 0255 Calculation of wave effects on water structures and to quantify the effect of current on the wave run-up height. and Jednou ze základních otázek spojených s bezpečností hráze je návrh převýšení její koruny nad maximální hladinou vzdouvané vody. Důležitým parametrem ovlivňujícím návrh převýšení je výška vln vybíhajících po svahu hráze. Běžné postupy výpočtu výšky výběhu vlny na svah jsou realizovány za předpokladu, že vlny vznikají na stojatých vodách. Vliv proudění se obvykle vzhledem k nízké úrovni znalostí tohoto jevu na tekoucích vodách zanedbává. V podmínkách České Republiky je otázka vlivu proudění na výšku výběhu relevantní zejména na velkých tocích jako Labe, Vltava nebo Morava. V rámci projektů Hydralab III a NAZV QI 92A139 byl uskutečněn hydraulický výzkum a analýza dat se speciálním zaměřením na výšku výběhu větrových vln při započtení vlivu proudění. Výzkum byl realizován na modelu hráze se sklonem svahu 1 : 3, který byl umístěn ve zkušební nádrži osazené vlnoproduktorem vedeným rovnoběžně s modelem hráze. Vlny zde byly generovány jednak kolmo vzhledem k podélné ose hráze, jednak šikmo v rozsahu úhlů ± 30°. Výsledky výzkumu byly porovnány s doporučeními uvedenými v České státní normě ČSN 75 0255 Výpočet účinků vln na stavby na vodních nádržích a zdržích.
Influence of the pattern of effective rainfall on modeled hydrograph was investigated in the study. The modelling was performed with the U.S. Army Corps of Engineers hydrograph package HEC-HMS 3.2 and calibrated and validated on measured hydrographs of Glinscica watershed. Six different models of rainfall loss were applied and their effect on modeled hydrograph was evaluated. Peak discharge, time of peak discharge and runoff volume were compared. The best results with the lowest RMSE in the study was obtained with the SCS curve number loss method. Also synthetic hyetographs of different probability and duration were used. Three positions of the maximum rainfall intensity at 25, 50 and 75 % of the rainfall duration were applied. The results showed essential differences in simulated time to peak and also differences in peak discharge. The differences in time to peak increases considerably with the increasing of the rainfall duration. Finally, the results of constant intensity distribution of rainfall of different durations were compared with those obtained with typical rainfall distribution with the position of the maximum intensity at 50 %. Results showed considerable differences in peak discharge and time to peak by longer durations of the rainfall. and Práca obsahuje výsledky výskumu vplyvu efektívnych zrážok na modelovaný hydrograf. Odtok bol modelovaný pomocou nástroja U.S. Army Corps of Engineers hydrograph package HEC-HMS 3.2, potom kalibrovaný a verifikovaný na meraných hydrografoch povodia Glinscica. Vplyv zrážok na modelovaný hydrograf bol vypočítaný pre šesť rôznych modelov priebehu zrážok. Porovnali sme maximálne prietoky, časy ich trvania a odtečené množstvá. Najlepšie výsledky s najnižším RMSE sme získali s SCS modelom odtoku. Použili sme tiež syntetické hyetografy rozdielnej pravdepodobnosti a trvania. Použili sa tri polohy maximálnych intenzít zrážok; pre 25, 50 a 75 % ich trvania. Výsledky ukázali zásadný rozdiel v simulovaných časoch maximálneho prietoku a tiež rozdiely v maximálnych prietokoch. Rozdiely v časoch dosiahnutia maximálnych odtokov sa výrazne zvyšovali s časom trvania zrážky. Nakoniec sme porovnali výsledky výpočtov s konštantnými intenzitami rozdelenia s rôznym trvaním zrážky s tými, ktoré boli vypočítané s použitím typických rozdelení, s polohou maximálnej intenzity zrážok pri 50 % ich trvania. Výsledky ukazujú významné rozdiely v maximálnych prietokoch a v časoch ich dosiahnutia v závislosti od trvania zrážky.
The present study focuses on the possible influence of large-scale climatic patterns on precipitation, temperature, and discharge in two distinct river basins in the Czech Republic. The first one is a flat lowland basin of the Cidlina River and the second one represents a more mountainous type of climate (the Blanice River). The large-scale climatic patterns used comprise monthly averages of teleconnection patterns, sea level pressure values, and two geopotential heights (850 hPa and 500 hPa). The correlations for corresponding months and also up to a three months lead time were investigated. The relations concerning the corresponding months proved to be most reliable in the winter period of the year. The behaviour of both selected river basins with respect to these predictors is rather similar in character. However, higher values of correlation coefficients are reached in the case of the Cidlina River basin. Considering the prediction abilities with a certain lead time, the results seem to be more promising for the winter and spring periods in both basins. In the Cidlina River basin, they are likely to be beneficial also for the late summer and autumn period.
Substantial evidence shows that the frequency of hydrological extremes has been changing and is likely to continue to change in the near future. Non-stationary models for flood frequency analyses are one method of accounting for these changes in estimating design values. The objective of the present study is to compare four models in terms of goodness of fit, their uncertainties, the parameter estimation methods and the implications for estimating flood quantiles. Stationary and non-stationary models using the GEV distribution were considered, with parameters dependent on time and on annual precipitation. Furthermore, in order to study the influence of the parameter estimation approach on the results, the maximum likelihood (MLE) and Bayesian Monte Carlo Markov chain (MCMC) methods were compared. The methods were tested for two gauging stations in Slovenia that exhibit significantly increasing trends in annual maximum (AM) discharge series. The comparison of the models suggests that the stationary model tends to underestimate flood quantiles relative to the non-stationary models in recent years. The model with annual precipitation as a covariate exhibits the best goodness-of-fit performance. For a 10% increase in annual precipitation, the 10-year flood increases by 8%. Use of the model for design purposes requires scenarios of future annual precipitation. It is argued that these may be obtained more reliably than scenarios of extreme event precipitation which makes the proposed model more practically useful than alternative models.
Longwave radiation, as part of the radiation balance, 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 FAO24 (relying on the measured sunshine duration) and FAO56 (based on the measured solar radiation) manuals. The performance of these equations was evaluated in the April–October period over eight years at the Liz experimental catchment and grass surface in the Bohemian Forest (Czech Republic). The coefficients of both methods, which describe the influence of cloudiness factor and atmospheric emissivity of the air, were calibrated. The Penman-Monteith method was used to calculate the PET. The use of default coefficient values gave errors of 40–100 mm (FAO56) and 0–20 mm (FAO24) for the seasonal PET estimates (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.