An accurate representation of reality in numerical variably-saturated flow models requires reliable estimates of necessary model parameters. Inverse modeling seeks to estimate parameters such as the saturated and residual water contents, the saturated hydraulic conductivity, the shape parameters of the soil hydraulic functions, using easily attainable observations of actual or cumulative water fluxes, pressure heads, water contents, and concentrations. The inverse procedure usually combines the nonlinear leastsquares-based (SSQ) parameter optimization method with a numerical solution of the variably-saturated flow and transport equations. The SSQ-based inverse method is however sensitive to outliers. A novel Squared ε-Insensitive Loss Function (SILF) approach is introduced in this study. The SILF approach is inspired by the ε-insensitive loss function proposed by Vapnik (1995). The objective function used in the SILF approach is similar to the least-squares objective function, except that it penalizes only for errors greater than a certain predefined acceptable error term ε. The SILF approach shows an improved performance over the SSQ approach in estimating the soil hydraulic parameters. Apart from providing robust estimates of the soil hydraulic parameters, the SILF approach also gives an approximation of the relative measurement error during sampling. and Presná reprezentácia skutočností v numerických modeloch prúdenia vo vodou nenasýtenej pôde vyžaduje spoľahlivé určenie potrebných parametrov modelu. Inverzným modelovaním sa snažíme o určenie takých parametrov, ako sú reziduálna vlhkosť pôdy, nasýtená hydraulická vodivosť, tvarové parametre hydraulických funkcií pôdy, využijúc ľahko realizovateľné pozorovania momentálnych alebo kumulatívnych tokov vody, tlakových výšok, vlhkostí pôdy a koncentrácií rozpustených látok. Inverzná procedúra obyčajne kombinuje nelineárnu optimalizáciu parametrov založenú na metóde najmenších štvorcov (SSQ) s numerickým riešením transportných rovníc vo vodou nenasýtenej pôde. Táto metóda (SSQ) je však citlivá na náhodné chyby. Nová, necitlivostná stratová funkcia s necitlivosťou ε(SILF), použitá v tejto štúdii, bola inšpirovaná návrhom publikovaným Vapnikom (1995). Optimalizovaná funkcia použitá v prístupe SILF je podobná tej, ktorá sa používa v metóde najmenších štvorcov s tou výnimkou, že táto penalizuje len chyby väčšie ako je určitá preddefinovaná akceptovateľná chyba ε. Pri určovaní hydraulických parametrov pôdy táto metóda SILF preukázala svoje prednosti pred prístupom SSQ. Okrem toho, že metóda SILF dáva robustné odhady hydraulických parametrov pôdy, umožňuje tiež aproximáciu relatívnych chýb merania počas odberu vzoriek.
Land use change is a phenomenon appearing in many part of world, not only in a local scale, but also at global level. This phenomenon can be resulting from climatic variation or from human activities on the land surface. It is rightfully assumed that the vegetation cover has a key impact on the rainfall-runoff process. For instance induced deforestation may cause disastrous flood; (after the flood in the Odra River and the Morava River basin in 1997 this phenomenon has been frequently disscussed). Among the appropriate tools to study the rainfall-runoff process changes are hydrological models. In the present work, three lumped conceptual models have been used, each emphasizing more or less processes which contribute to the water cycle on the landscape and in deeper zones. The model SAC-SMA, the BROOK´90 and the TOP-model have been used for the investigation in the hilly basin of Vltava River at Lenora. A daily time step has been used for all the models. Although the models have different structures, their results indicate similar tendency in runoff differences. and Změny ve využívání krajiny jsou procesem, objevujícím se v různých místech na Zemi, nejen na lokální úrovni, ale i v globálním měřítku. Proměnlivost odtoku je jednak důsledkem klimatické variability a jednak lidské činnosti v povodí. Všeobecně je uznáván klíčový význam vegetační pokrývky pro vývoj srážko-odtokového procesu. Zejména nucené odlesňování může způsobovat ničivé povodně; to bylo námětem častých diskusí i o povodni na Moravě a Odře v roce 1997. Mezi vhodné nástroje pro zkoumání jeho různých aspektů lze bezpochyby zařadit hydrologické modely. V předkládané práci byly pro daný účel užity tři různé modely srážko-odtokového procesu, zvýrazňující více či méně různé části hydrologického cyklu na povrchu území, či v podpovrchových zónách. V experimentech pro horskou část povodí Vltavy po Lenoru byly pro hodnocení odtokových změn užity modely SAC-SMA, BROOK´90 a TOPmodel. Pro simulace byly k dispozici denní časové řady srážek, odtoků a teplot vzduchu z období 40 roků. I když struktura užitých modelů je odlišná, výsledky indikují jasné a podobné tendence ve změnách odtokových diferencí.
Investigations indicate that correct estimation of seasonal thermal stratification in a dam reservoir is very important for the dam reservoir water quality modeling and water management problems. The main aim of this study is to develop a hydrodynamics model of an actual dam reservoir in three dimensions for simulating a real dam reservoir flows for different seasons. The model is developed using nonlinear and unsteady continuity, momentum, energy and k-ε turbulence model equations. In order to include the Coriolis force effect on the flow in a dam reservoir, Coriolis force parameter is also added the model equations. Those equations are constructed using actual dimensions, shape, boundary and initial conditions of the dam and reservoir. Temperature profiles and flow visualizations are used to evaluate flow conditions in the reservoir. Reservoir flow’s process and parameters are determined all over the reservoir. The mathematical model developed is capable of simulating the flow and thermal characteristics of the reservoir system for seasonal heat exchanges. Model simulations results obtained are compared with field measurements obtained from gauging stations for flows in different seasons. The results show a good agreement with the field measurements.
This paper's primary purpose is to show that there is a peculiar alternative to scientism whose central thesis is not about sources of knowledge or the existence of various objects, but it aims at setting out a strategy to help decide which of the two mutually exclusive beliefs is the better one to adopt. Scientophilia, to coin a term, recommends preferring, without any discussion, a position consistent with the consensus of credible and reliable experts in a given domain. In case there is no such agreement, mainly because peers disagree with each other, or experts are difficult to identify, it is recommended for a scientophile to suspend judgment. Scientophilia is not a position on science or human knowledge boundaries, but it deals with the practical side of belief change. Verdicts made by this approach are partially similar to those offered by mild scientism, as scientophilia puts scientific knowledge as one of the most reliable sources. However, it is also consistent with mild antiscientism, as in some particular cases (for example, Moorean truths), it assigns reliable expertise to non-scientific experts. Therefore it is a third way.
Isothermal and non-isothermal infiltration experiments with tracer breakthrough were carried out in the laboratory
on one intact column (18.9 cm in diameter, 25 cm in height) of sandy loam soil. For the isothermal experiment, the
temperature of the infiltrating water was 20°C to the initial temperature of the sample. For the two non-isothermal experiments
water temperature was set at 8°C and 6°C, while the initial temperature of the sample was 22°C. The experiments
were conducted under the same initial and boundary conditions. Pressure heads and temperatures were monitored in two
depths (8.8 and 15.3 cm) inside the soil sample. Two additional temperature sensors monitored the entering and leaving
temperatures of the water. Water drained freely through the perforated plate at the bottom of the sample by gravity and
outflow was measured using a tipping bucket flowmeter. The permeability of the sample calculated for steady state stages
of the experiment showed that the significant difference between water flow rates recorded during the two experiments
could not only be justified by temperature induced changes of the water viscosity and density. The observed data
points of the breakthrough curve were successfully fitted using the two-region physical non-equilibrium model. The results
of the breakthrough curves showed similar asymmetric shapes under isothermal and non-isothermal conditions.
The article synthesizes available information on isotopic composition of precipitation in Slovakia (the Western Carpathians). Monthly δ18O data from eleven stations and period 1988-1997 were used to investigate correlations among the stations, altitude, air temperature and precipitation amount effects. The mean annual altitude and air temperature gradients of δ18O in precipitation were 0.21‰/100 m and 0.36‰/1°C, respectively. Maps of spatial distribution of mean annual δ18O in precipitation based on both gradients were constructed. The two maps do not significantly differ for the majority of Slovakia. δ2 H data were available for only three stations. Local meteoric water line derived for the station with the longest data series (δ2 H = = 7.86δ18O + 6.99) was close to the Global Meteoric Water line. Its parameters in periods 1991-1993 and 1991-2008 did not change. The study indicates that a more detailed monitoring of isotopic composition of precipitation in mountains should be carried out in the future. The highest station exhibited very small seasonal variability of δ18O in precipitation compared to other Slovak stations. The second highest mountain station had significantly higher deuterium excess than the neighboring stations located in the valley. In some analyses the data from the nearest stations situated abroad (Vienna, Krakow) were used. and Príspevok syntetizuje dostupné údaje o izotopickom zložení zrážok na území Slovenska (Západné Karpaty). Hodnotí koreláciu hodnôt δ18O v kumulatívnych mesačných zrážkach z rokov 1988-1997 medzi jednotlivými stanicami, vplyv nadmorskej výšky, teploty vzduchu a úhrnu zrážok. Priemerný ročný výškový gradient δ18O v zrážkach je 0,21‰/100 m, priemerný ročný teplotný gradient δ18O v zrážkach je 0,36‰/1°C. Oba gradienty boli použité na vytvorenie mapy priestorového rozdelenia δ18O v zrážkach na území Slovenska. Mapa vytvorená pomocou výškového gradientu δ18O v zrážkach sa pre väčšinu územia Slovenska významne nelíši od mapy vytvorenej pomocou teplotného gradientu. Hodnoty δ2 H v zrážkach boli k dispozícii len pre tri stanice na Slovensku. Pre stanicu s najdlhším radom údajov (1991-2008) bola určená lokálna meteorická čiara (δ2 H = 7.86δ18O + 6.99), ktorej priebeh je blízky globálnej meteorickej čiare. Parametre lokálnej meteorickej čiary sa počas skúmaného obdobia nezmenili. Merané mesačné údaje poukazujú na potrebu podrobnejšieho monitoringu izotopického zloženia zrážok v horách. Najvyššie ležiaca stanica mala v porovnaní s ostatnými stanicami veľmi malú sezónnu variabilitu δ18O v zrážkach. Druhá najvyššie položená stanica mala podstatne vyšší exces deutéria, ako susedné stanice ležiace v kotlinovej polohe. Pri niektorých analýzach boli údaje zo Slovenska porovnávané s najbližšie ležiacimi zahraničnými stanicami (Viedeň, Krakov).