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1253. Theory of evapotranspiration. 1.. Transpiration and its quantitative description

Creator:
Budagovskyi, Anatolij Ivanovič and Novák, Viliam
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
evapotranspiration, transpiration, evaporation, soil water, water balance, evapotranspirácia, transpirácia, evaporácia, pôdna voda, and bilancia vody
Language:
Slovak
Description:
Basic information about the evapotranspiration and its components is presented. System of equations describing the transport of water and energy in the soil - plant continuum is analyzed. The system of five differential equations with five unknowns is proposed, describing transport of heat and water vapour within the plant canopy, including exchange processes among the leaves and the atmosphere, vertical transport of the heat, water vapour and the energy balance. and Príspevok obsahuje základné informácie o evapotranspirácii a jej zložkách, výpare a transpirácii. Proces prenosu vody a energie v systéme pôda - porast je opísaný systémom piatich diferenciálnych rovníc kvantifikujúcich prenos vodnej pary a tepla medzi listami a atmosférou, ktoré umožnujú výpočet charakteristík vertikálneho prenosu vody a tepla v poraste a tiež bilanciu energie v tomto systéme.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1254. Theory of evapotraspiration. 2.. Soil and intercepted water evaporation

Creator:
Budagovskyi, Anatolij Ivanovič and Novák, Viliam
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
evapotranspiration, transpiration, evaporation, soil water, water balance, evapotranspirácia, transpirácia, evaporácia, pôdna voda, and bilancia vody
Language:
Slovak
Description:
Evaporation of water from the soil is described and quantified. Formation of the soil dry surface layer is quantitatively described, as a process resulting from the difference between the evaporation and upward soil water flux to the soil evaporating level. The results of evaporation analysis are generalized even for the case of water evaporation from the soil under canopy and interaction between evaporation rate and canopy transpiration is accounted for. Relationships describing evapotranspiration increase due to evaporation of the water intercepted by canopy are presented. Indirect methods of evapotranspiration estimation are discussed, based on the measured temperature profiles and of the air humidity, as well as of the net radiation and the soil heat fluxes. and Príspevok obsahuje kvantitatívny opis výparu vody z pôdy a bilanciu energie počas vyparovania, charakterizovanú rovnicou obsahujúcou turbulentný tok tepla a skupenské teplo vyparovania. Je opísaný proces tvorby suchej vrstvy na povrchu pôdy počas výparu; jeho tvorba závisí od rozdielu medzi rýchlosťou výparu a prítokom vody k horizontu výparu zo spodnej vrstvy pôdy.Výsledky analýzy možno použiť aj na kvantifikáciu výparu z pôdy pod porastom. Uvádzajú sa vzťahy na výpočet zvýšenia rýchlosti evapotranspirácie, spôsobenej intercepciou. Práca obsahuje analýzu nepriamych metód výpočtu evapotranspirácie, ktoré sú založené na meraní profilov teploty a vlhkosti vzduchu nad vyparujúcim povrchom, ako aj radiačnej bilancie a tokov tepla v pôde.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1256. Three-dimensional flow of an Oldroyd-B fluid over a bidirectional stretching surface with prescribed surface temperature and prescribed surface heat flux

Creator:
Hayat, Tasawar, Shehzad, Sabir Ali, Al-Mezel, Saleh, and Alsaedi, Ahmed
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
three-dimensional flow, Oldroyd-B fluid, bidirectional stretching surface, and heat source/sink
Language:
Slovak
Description:
This paper concentrates on the mathematical modelling for three-dimensional flow of an incompressible Oldroyd-B fluid over a bidirectional stretching surface. Mathematical formulation incorporates the effect of internal heat source/sink. Two cases of heat transfer namely the prescribed surface temperature (PST) and prescribed surface heat flux (PHF) are considered. Computations for the governing nonlinear flow are presented using homotopy analysis method. Comparison of the present analysis is shown with the previous limiting result. The obtained results are discussed by plots of interesting parameters for both PST and PHF cases. We examine that an increase in Prandtl number leads to a reduction in PST and PHF. It is noted that both PST and PHF are increased with an increase in source parameter. Further we have seen that the temperature is an increasing function of ratio parameter.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1257. Time of concentration of surface flow in complex hillslopes

Creator:
Sabzevari, Touraj, Saghafian, Bahram, Talebi, Ali, and Ardakanian, Reza
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
complex hillslopes, time of concentration, and surface flow
Language:
Slovak
Description:
Time of concentration (TC) of surface flow in watersheds depends on the coupled response of hillslopes and stream networks. The important point in this background is to study the effects of the geometry and the shape of complex hillslopes on the time of concentration considering the degree of flow convergence (convergent, parallel or divergent) as well as the profile curvature (concave, straight or convex). In this research, the shape factor of complex hillslopes as introduced by Agnese et al. (2007) is generalized and linked to the TC. A new model for calculating TC of complex hillslopes is presented, which depends on the plan shape, the type and degree of profile curvature, the Manning roughness coefficient, the flow regime, the length, the average slope, and the excess rainfall intensity. The presented model was compared to that proposed by Singh and Agiralioglu (1981a,b) and Agiralioglu (1985). Moreover, the results of laboratory experiments on the travel time of surface flow of complex hillslopes were used to calibrate the model. The results showed that TC for convergent hillslopes is nearly double those of parallel and divergent ones. TC in convex hillslopes was very close to that in straight and concave hillslopes. While the effect of convergence on TC is considerable, the curvature effect confirmed insignificant. Finally, in convergent hillslopes, TC increases with the degree of convergence, but in divergent hillslopes, it decreases as degree of divergence increases.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1258. Time sensitivity and acceptance of testimony

Creator:
Alsamaani, Nader
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
acceptance of testimony, time sensitivity, reductionism, and non-reductionism
Language:
Slovak
Description:
Time sensitivity seems to affect our intuitive evaluation of the reasonable risk of fallibility in testimonies. All things being equal, we tend to be less demanding in accepting time sensitive testimonies as opposed to time insensitive testimonies. This paper considers this intuitive response to testimonies as a strategy of acceptance. It argues that the intuitive strategy, which takes time sensitivity into account, is epistemically superior to two adjacent strategies that do not: the undemanding strategy adopted by non-reductionists and the cautious strategy adopted by reductionists. The paper demonstrates that in adopting the intuitive strategy of acceptance, one is likely to form more true beliefs and fewer false beliefs. Also, in following the intuitive strategy, the listener will be fulfilling his epistemic duties more efficiently.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

1259. Time series analysis of hydrologic data for water resources planning and management: a review

Creator:
Machiwal, Deepesh and Jha, Madan K.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
time series analysis techniques, review, climatologic time series, hydrologic time series, water resources planning and management, techniky analýzy časových radov, prehľad, časové rady v hydrológii, časové rady v klimatológii, vodohospodárske plánovanie, and riadenie vodného hospodárstva
Language:
Slovak
Description:
The main intent of this paper is to present a review on the application of time series analysis techniques in hydrology and climatology. An overview of various statistical tests for detecting and estimating the hydrologic time series characteristics (i.e., homogeneity, stationarity, trend, periodicity, and persistence) is presented, together with their merits and demerits followed by comprehensive reviews of past studies (both basic and applied), and future research directions. The present review revealed that the climatologic time series of precipitation, air temperature, evapotranspiration and climatic change, and the hydrologic time series of streamflow and surface water quality have received a great deal of attention worldwide. Although the application areas of time series analysis techniques are expanding with growing concerns about climate change and global warming, their application is still very limited in groundwater hydrology as well as for non-traditional hydrologic time series. It is also apparent from this review that the detection of trend and stationarity by parametric and/or nonparametric tests has been a major focus in the past. Multiple comparison tests lack appreciation by the researchers for testing homogeneity in the hydrologic and climatologic time series. Furthermore, most studies have ignored the importance of testing periodicity and persistence in the time series, which are equally important properties of hydrologic and climatologic time series. Based on the comprehensive review, future research needs for time series studies in hydrology and climatology are discussed. and Príspevok prináša prehľad aplikácií techník analýzy časových radov v hydrológii a klimatológii. Uvádza prehľad rôznych štatistických testov na zistenie charakteristík týchto radov (napr. homogenity, stacionarity, trendov, periodicity a perzistencie), spolu s ich prednosťami a nedostatkami. Ďalej je uvedený tiež celkový prehľad uskutočnených štúdií (základných aj aplikovaných) a smery výskumu pre budúcnosť. Súčasný prehľad naznačuje celosvetové sústredenie pozornosti na časové súbory klimatologických dát zrážok, teploty vzduchu, evapotranspirácie a zmien klímy, a tiež hydrologických dát prietokov a kvality povrchových vôd. Aj keď so zvýšením záujmu o zmenu klímy a globálne otepľovanie sa oblasti použitia techník analýzy časových radov rozširujú, ich aplikácie v oblasti hydrológie podzemných vôd a ďalších nie celkom tradičných hydrologických údajov sú veľmi obmedzené. Tento prehľad tiež uvádza, že v minulosti sa vyskytli snahy o sústredenie úsilia na postihnutie trendov a stacionarity radov použitím parametrických a/alebo neparametrických testov. Mnohí výskumníci dostatočne neoceňujú viacnásobné porovnávacie testy (multiple comparison tests) homogenity hydrologických a klimatických časových radov. Okrem toho vo väčšine štúdií sú zanedbané dôležité testy periodicity a perzistencie hydrologických radov. Tieto sú ich rovnako dôležité charakteristiky. Na základe všeobecného prehľadu príspevok tiež pojednáva o potrebe ďalšieho výskumu časových radov v hydrológii a klimatológii.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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