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2672. Vztahy mezi vodní hodnotou sněhu v zalesněném terénu a na otevřeném prostranství v experimentálních povodích Jizerských hor

Creator:
Stehlík, Jiří and Bubeníčková, Libuše
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
snow water equivalent, snow water storage, forest and open area, the Jizera Mts, vodní hodnota sněhu, sněhové zásoby, les a otevřené prostranství, and Jizerské hory
Language:
Slovak
Description:
The study deals with the analyses of long-term snow measurements performed in the top-parts of the Jizera Mts. The homogenity of the measured data and the relationship between the snow cover parameters and elevation are tested. The main task is to determine the amount of snow sotrage in forest based on the measurements in open areas. It was proved that: i) the relationships can be defined by means of simple linear regression, ii) the resulting equations differ during the winter season depending on snow accumulation and snow melting periods respectively. The results re the first step in the research which will continue with analyses from other sites in Jizera mountains and new established measurements in the selected climatological stations. and Článek se zabývá analýzou sněhoměrných měření prováděných dlouhodobě ve vrcholových partiích Jizerských hor. Testována je homogenita naměřených dat a závislost parametrů sněhové pokrývky na nadmořské výšce. Jádrem práce je však zjišťování vztahů pro výpočet sněhových zásob v lesním prostředí na základě měření z volných prostranství. Bylo prokázáno, že i)tyto převodní vztahy lze odvodit pomocí jednoduché lineární regrese, ii)výsledné rovnice se liší během zimního období - pro období akumulace sněhové pokrývky jsou jiné než pro období tání. Výsledky jsou prvním krokem výzkumu, který bude pokračovat analýzami dalších profilů v Jizerských horách a nově zaváděných měření na souboru vybraných klimatických stanic.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2673. Vztahy Slunce - Země: seminář Praha, říjen 1983

Creator:
Ryš, Přemysl, Bumba, Václav, Vědecké kolegium geologie a geografie ČSAV Praha, Slovenské ústredie amatérskej astronómie Hurbanovo, and Vztahy Slunce - Země (1983 : Praha, Česko)
Publisher:
Vědecké kolegium astronomie a geofyziky ČSAV
Format:
print and 247 s. : obr., tab.
Type:
model:monograph and TEXT
Subject:
Astronomie, astronomie, geofyzika, 52, 550.3, (062.534), and 6
Language:
Czech and Slovak
Description:
P. Ryš, V. Bumba ... [et al.]. and Část. slovenský text
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2675. Warming Vistula River - the effects of climate and local conditions on water temperature in one of the largest rivers in Europe

Creator:
Ptak, Mariusz, Sojka, Mariusz, Graf, Renata, Choiński, Adam, Zhu, Senlin, and Nowak, Bogumił
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
water temperature, transit rivers, trends, transformation factors, and Central Europe
Language:
Slovak
Description:
The paper evaluates changes in the water temperature of the Vistula River – one of the longest rivers in Europe. Mean monthly and annual water temperatures from the period 1971–2017 for 11 stations along the entire length of the river revealed the increasing trends. The mean increase in water temperature in the analysed multi-annual period was 0.31 °C dec–1. In the majority of analysed stations, the key factor determining changes in the water temperature of the river was air temperature. The observed water warming in the Vistula River should be considered an exceptionally unfavourable situation in the context of importance of water temperature for a number of processes and phenomena occurring in river ecosystems. Given the scale of changes, fast measures should be undertaken to slow down the warming.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2677. Water flow in a single fracture with variable aperture

Creator:
Veselý, Marek and Mls, Jiří
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
fracture flow, variable aperture, percolation probability, contact area, puklinové proudění, proměnlivé rozevření, perkolační pravděpodobnost, and kontaktní plocha
Language:
Slovak
Description:
Water flow in a single fracture with variable aperture was studied by means of numerical modeling. For this purpose, two numerical models were developed. Computer simulations of water flow rates, fracture contact areas and transmissivities for fractal and nonfractal fractures were performed. Water flow rates were approximated by a trend function. The effect of the grid size upon the stability of results as well as the dependence of the fracture transmissivity on rate of contact area were studied. The achieved results were compared with measured data. and Studie se věnuje proudění podzemní vody v samostatné puklině metodou numerického modelování. K tomu účelu jsme vyvinuli dva numerické modely. Byly provedeny série numerických simulací proudění vody a výpočtu kontaktní plochy a transmisivity pukliny pro obecný typ pukliny. Byly studovány vliv velikosti sítě generované pukliny na stabilitu perkolačních charakteristik a závislost propustnosti pukliny na poměrné velikosti kontaktní plochy. Získané výsledky byly vyhodnocovány ve vztahu ke známým experimentálním datům.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2678. Water infiltration in an aquifer recharge basin affected by temperature and air entrapment

Creator:
Loizeau, Sébastien, Rossier, Yvan, Gaudet, Jean-Paul, Refloch, Aurore, Besnard, Katia, Angulo-Jaramillo, Rafael, and Lassabatere, Laurent
Type:
article, model:article, and TEXT
Subject:
aquifer recharge, unsaturated/saturated modeling, infiltration test, air entrapment, and temperature dependence
Language:
Slovak
Description:
Artificial basins are used to recharge groundwater and protect water pumping fields. In these basins, infiltration rates are monitored to detect any decrease in water infiltration in relation with clogging. However, miss-estimations of infiltration rate may result from neglecting the effects of water temperature change and air-entrapment. This study aims to investigate the effect of temperature and air entrapment on water infiltration at the basin scale by conducting successive infiltration cycles in an experimental basin of 11869 m2 in a pumping field at Crepieux-Charmy (Lyon, France). A first experiment, conducted in summer 2011, showed a strong increase in infiltration rate; which was linked to a potential increase in ground water temperature or a potential dissolution of air entrapped at the beginning of the infiltration. A second experiment was conducted in summer, to inject cold water instead of warm water, and also revealed an increase in infiltration rate. This increase was linked to air dissolution in the soil. A final experiment was conducted in spring with no temperature contrast and no entrapped air (soil initially water-saturated), revealing a constant infiltration rate. Modeling and analysis of experiments revealed that air entrapment and cold water temperature in the soil could substantially reduce infiltration rate over the first infiltration cycles, with respective effects of similar magnitude. Clearly, both water temperature change and air entrapment must be considered for an accurate assessment of the infiltration rate in basins.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

2679. Water repellency decreases with increasing carbonate content and pH for different biocrust types on sand dunes

Creator:
Drahorad, Sylvie Laureen, Felde, Vincent J. M. N. L., Ellerbrock, Ruth H., and Henss, Anja
Format:
počítač and online zdroj
Type:
model:article and TEXT
Subject:
organic matter composition, surface characteristics, TOF-SIMS, biocrust, carbonate content, and water repellency
Language:
Slovak
Description:
Biocrusts are biological communities that occupy the soil surface, accumulate organic matter and mineral particles and hence strongly affect the properties of the soils they cover. Moreover, by affecting water repellency, biocrusts may cause a preferential infiltration of rainwater, with a high impact on the formation of local water pathways, especially for sand dunes. The aim of this study is to shed light on the connections between water repellency and pH, carbonate and organic matter content in two dune ecosystems with different biocrust types. For this, we used contact angle measurements, gas volumetric carbonate determination and organic matter characterization via FT-IR and TOFSIMS. In both ecosystems, moss-dominated biocrusts showed higher water repellency and higher amounts of organic matter compared to algal or cyanobacterial biocrusts. Surprisingly, the biocrusts of the two dune systems did not show differences in organic matter composition or organic coatings of the mineral grains. Biocrusts on the more acidic dunes showed a significantly higher level of water repellency as compared to higher carbonate containing dunes. We conclude that the driving factor for the increase in water repellency between cyanobacterial and moss-dominated biocrusts within one study site is the content of organic matter. However, when comparing the different study sites, we found that higher amounts of carbonate reduced biocrust water repellency.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2680. Water stable aggregates of Japanese Andisol as affected by hydrophobicity and drying temperature

Creator:
Leelamanie, D.A.L. and Karube, Jutaro
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
aggregate stability, contact angle, floating time, Japanese Andisol, hydrophobicity, and wetting rate
Language:
Slovak
Description:
Hydrophobicity is a property of soils that reduces their affinity for water, which may help impeding the pressure build-up within aggregates, and reducing aggregate disruption. The purpose of this study was to examine the relation of soil hydrophobicity and drying temperature to water stability of aggregates while preventing the floating of dry aggregates using unhydrophobized and hydrophobized surface Andisol. Soil was hydrophobized using stearic acid into different hydrophobicities. Hydrophobicity was determined using sessile drop contact angle and water drop penetration time (WDPT). Water stability of aggregates (%WSA) was determined using artificially prepared model aggregates. The %WSA increased as the contact angle and WDPT increased. Contact angle and WDPT, which provided maximum %WSA showing less than 1 s of floating, was around 100° and 5 s, respectively. Although the %WSA gradually increased with increasing contact angle and WDPT above this level, high levels of hydrophobicity initiated aggregate floating, which would cause undesirable effects of water repellency. Heating at 50°C for 5 h d-1 significantly affected %WSA and hydrophobicity in hydrophobized samples, but did not in unhydrophobized samples. The results indicate that the contact angle and wetting rate (WDPT) are closely related with the water stability of aggregates. The results further confirm that high levels of hydrophobicities induce aggregate floating, and the drying temperature has differential effects on hydrophobicity and aggregate stability depending on the hydrophobic materials present in the soil.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

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