Modeling the Effect of Waves on the Diurnal Temperature Stratification of a Shallow Lake

In this paper a three-dimensional circulation model has been applied to determine the spatial distribution of the temperature and mixed-layer depth (MLD) of a medium-sized shallow lake. In order to reproduce the vertical thermal structure of the lake, the impact of waves has been incorporated using several recently published schemes. These schemes approximate the additional mixing due to the orbital motion of waves, the turbulent kinetic energy produced by waves, or both. The reference solver is the Reynolds-Averaged Navier-Stokes equations with two-equation Mellor-Yamada 2.5 turbulence closure. The wave field is characterized by bulk parameters, e.g. significant wave height. The sensitivity to the choice of the wave mixing scheme is analyzed by means of an academic test case. The accuracy of the scheme is explored through data collected in Lake Balaton. The modeled temperature profiles and MLDs match measurements much better when the effect of non-breaking surface waves is included

On the 2D modelling aspects of wind-induced waves in shallow, fetch-limited lakes

Wind-induced waves play an important role in shallow lake hydro- and sediment dynamics. But most of the field measurement methods can give information about the wave properties only at single point, which calls for wave estimation methods to take the effect of waves into account in multidimensional hydro- and sediment dynamic models. The aim of this study is to improve modelling waves in depth- and fetch-limited lakes generated by the local winds. In the first part of this paper, we describe the calibration and validation of the 2D spectral wave model SWAN (Simulating Waves Nearshore) to the very shallow Lake Neusiedl, Hungary/Austria. The abrupt change of the roughness at the perimeter of the open lake and the gradual change along the fetch due to wave growth result in a systematic, fetch-dependent variation of the wind speed. This spatial inhomogeneity is modelled here by a 1D atmospheric internal boundary layer (IBL) model. It is shown in the second part of this paper that this approach results in a significant effect on wave parameters and, as a consequence, on bottom shear stress

Wind Shear Stress Interpolation over Lake Surface from Routine Weather Data Considering the IBL Development

In this paper a simple diagnostic wind field calculation scheme is presented which provides a spatially variable wind stress field over the lake surface for hydrodynamic modeling purposes. The goal was to develop a scheme that requires routine wind time series as input from stations located over or around the lake. The main idea is to embed an internal boundary layer model within a horizontal interpolation scheme, in this case, with inverse-distance weighting. The wind model reproduces reasonably well the increment of wind stress along the fetch due to the abrupt roughness change at the shoreline and the gradual roughening of the wavy lake surface. The proposed method is validated with wind measurements observed around Lake Balaton and through hydrodynamic modeling. Sensitivity to the parameters is analyzed, including the effect of the temporal averaging of the wind

Surface Water–Groundwater Interactions and Bank Storage during Flooding: A Review

The interaction between river floods and groundwater not only replenishes groundwater resources, but also contributes to the attenuation of flood waves and is therefore a hydrologic factor in flood risk management. The magnitude of this interaction is expressed as bank storage, that is, the volume of the surface water that is temporarily stored in the riverbanks and slowly released back into the river after the peak of the flood wave. The amount of bank storage depends not only on the hydrograph of the river, but also on the morphology and hydrogeology of the river valley. This article offers a review of the current understanding and description of water exchange between the river and aquifer, with a focus on exchange due to flood events. The main field measurement methods of river-aquifer interactions, made to determine the properties of the aquifer, are summarized. The foundations of mathematical models are also reviewed, centered on how the surface and groundwater flow models are coupled, as well as on dimensional and process-related simplifications

Processes Towards Sedimentation around a Reed Island in a Shallow Lake

There are many studies on the hydromorphological impacts of emergent aquatic vegetation, but many of these focus on gravity-driven flows in riverine or tidal environments. However, an added effect of emergent vegetation in lakes is that it reduces the main external force (wind) significantly and in a spatially coherent way. We performed long Monte Carlo simulations using a 2D hydrodynamic model and a spectral wind wave model to study resuspension dynamics around a 100-m-wide reed island in southern Lake Fertő/Neusiedl. Wave-current interaction, computed in a post-processing step, was found to enhance maximum bed shear stresses only on the leeward side of the reed island, and even there to a small extent. We have found evidence that the present bed topography is close to an equilibrium where simulated combined wave-current shear stresses have a reasonably uniform exceedance probability over the critical shear stress of the bed sediment. We also found that an artificially flattened lakebed around the reed island would start evolving towards the present bed topography and grain size distribution (both of which were surveyed in the field). Despite the limitations of our modelling framework, our results illustrate the importance of how wind climate is translated to an uneven distribution of sediment entrainment around the reed island, explaining tendencies of sediment accumulation and sorting. Our results lead to a better understanding of the complicated processes involving interaction among wind, vegetation, circulation, wind waves, sediment and bathymetry

A repceolaj biológiai hatásának vizsgálata

Die Verfasserin untersucffte einige biologische Wirkungen des Rapsöls im Vergleich mit Sonnenblumenöl in Ratten. Es wurde festgestellt dass in 20% Rapsöl enthaltendes Futter verzehrenden Ratten im Vergleich zu den Sonnenblumenöl enthaltendes Futter verzehrenden Kontrollticren folgende Unterschiede festgestellt werden können: 1. Die Gewichtszunahme der Tiere verringert sich nach 4 Wochen,. 2. Das Gewicht der Leber ist in signifikantem Masse grösser geworden. 3. Erucasäure und Gadolensäure kann in jedem der untersuchten Organe und Gewebe nachgewiesen werden. Die Menge der Erucasäure ist von diesen Organen besonders im Herzen, in der Nebenniere und den Muskeln bedeutend, diejenige der Gadolensäure aber in der Nebenniere und den Muskeln. 4. Mit fortschreitender Fütterung steigt der Erucasäurcgehalt in dem Fettgewebe an, nimmt im Serum, der Leber und dem Herz ab, und bleibt in der Niere und der Nebenniere unverändert. Das Niveau der Gadolensäure nimmt in dem Fettgewebe zu, bleibt in den untersuchten Organen unverändert. 5. Der Cholesteringehalt der Leber, der Nebenniere und des Muskelgewebes ist signifikant höher. Aufgrund der obigen Resultate scheint die Erhöhung des Konsums bis zur Klärung der Wirkung des Rapsöls durch weitere Experimente und Beobachtung an Menschen nicht erwünscht. In experiments with rats, some of the biological effects of rape oil were compared with those of sunflower oil. It was found that in rats fed with feeds containing 20% of rape oil the following alterations were observed, in comparison with controls fed with feeds containing sunflower oil. 1. The weight increase of rats decreased after 4 weeks of feeding. 2. The weight of liver was significantly greater. 3. In all the examined organs and tissues, erucic acid and gadolenic acid were detectable. The quantity of erucic acid was particularly significant in the heart, adrenals and muscles (of the examined organs), that of gadolenic acid in the adrenals and in muscles. 4. With the advance of the feeding period the contents of eruricacid in the heart tissue increased, in the serum, liver and heart decreased, w'hereas no changes were observed in the kidneys and in the adrenals. The level of gadolenic acid increased in the fat tissue but did not alter in the other organs examined. 5. The cholesterol content was significantly higher in the liver, adrenals and muscles. On the basis of the above results the increase of the consumption of rape oil does not appear to be desirable until its effect is not cleared up by further experiments and observations on humans. L’auteur a effectué Pexamen comparé de quelques effets biologiques des huiles de colza et de tournesol dans des rats. Elle a constaté qu’en comparant les rats nourris d’un fourrage contenant 20 p. c. cThuile de colza aux rats controles nourris de fourrage contenant de l’huile de tournesol, les differences suivantes se font observer: 1. L’augmentation du poids des animaux diminue aprés 4 semaines. 2. Le poids du foie est signifiquamment plus élévé. 3. Les acides erouca et gadolene se font décéler dans tous les organes et tissus examinés. La quantité de l’acide erouca est particuliérement élevée dans le coeur, la glande surrénale et les muscles, celle de l’acide gadolénique cependant dans la glande surrénale et dans les muscles. 4. Avec l’avancement de la période d’affouragement la teneur en acide eroucaique augmente dans le tissu adipeux, diminue dans le sérum, le foie et le coeur et ne change pas dans les reins et dans la glande surrénale. Le niveau de Lacidé gadolénique augmente dans le tissu adipeux et ne varié pas dans les organes examinés. 5. Les teneurs en choléstérine du foie, de la glande surrénale et du tissu musculaire sont signifiquamment plus élevées. A partir de susdits résultats Laugmentation de la consommation de l’huile de colza ne semble pás désirable avant a mise au point de son effet ä l’aide d’expériences ultérieures effectuées sur des animaux ainsi que des observations faites s ir des hommes

Hajfestőszerek parafeniléndiamin tartalmának meghatározása papírkromatográfiás eljárással, egészségügyi megítélés céljából

Die Verfasser entwickelten ein analytisches Verfahren zur Bestimmung des p-Phenilendiamingehaltes von Haarfärbemitteln neben p-Toluidendiamin in Anwesenheit von p-Aminophenol oder Resorcin zwecks hygienischer Beurteilung. Die Methode besteht in papierchromatographischer Trennung der genannten Verbindungen vermittels der oberen Phase des Gemisches n-Butanol- conc. Salzsäure und dest. Wasser 7:2:4 und Densitometrierung und planimetrischer Auswertung der mit einer salzsauren Lösung von p-Dimethylaminobenzaldehyd oder einer ammoniakalischen H20 2-Lösung sichtbar gemachten Flecke. Das erstgenannte Reagens eignet sich zur Messung von 1 - 4 g, das andere zur Messung von 10-40 g Mengen von p-Phenilendiamin. Die Streung der mit der Methode erhaltenen Resultate (standardé Deviation) ist in beiden Fällen ±5%. Die praktische Verwendungsmöglichkeit des Verfahrens wird an einigen Beispielen illustriert. An analytical method for the determination of the content of p-phenylene diamine in the simultaneous presence of p-toluylene diamine, p-aminophenol or resorcinol is presented by the authors, in order to facilitate the hygienic evaluation of hair dyeing agents. The method consists in a paper chromatographic separation of the mentioned compounds with the upper phase of a 7 : 2 : 4 mixture of n-butanol, concentratei hydrochloric acid and distilled water, followed by the densitometric examination of the spots developed with a hydrochloric acid solution of p-dimethylaminobenzaldehyde or with an ammonia solution of hydrogen peroxide. The former reagent is applied in the measurement of pphenylene amounts of 1 to 4 g, while the latter reagent for that of quantities of 10 to 40 g of p-phenylene diamine. The standard deviations of the data obtained by the suggested method ranged with both reagents ±5%. The practical applicability of the method is sohwn is several examples. Les auteurs publient un procédé analvtique pour le dosage de la leneur en p-phénylénediatnine en présence de p-toluilénediamine et de p-aminophénol ou de resorcine dans le but de la qualification au point de vue hygiénique des teintures de cheveux. La méthode consiste en la séparation des cotnposants mentionnés par chromatogaphie sur papier, avec la phase supérieure obtenue ayec un mélange de n-butanol, d’acide chlorhydrique concentrée et d’eau ä 7:2:4, par le densimétrage des taches rendues visibles par une solution de p-diméthylaminobenzaldehyde dans de Pacidé chlorhydrique ou par une solution ammoniacale de H20 2 et finalcment par le mesurage planimétrique des taches. Le premier réactif peut servir pour le dosage de 1 ä 4 g de p-phénylénediamine et le second pour des quantités entre 10 et 40 g. La déviation standardé des résultats obtenus avec les deux méthodes est +5%. La praticabilité du procédé est demontrée sur quelques exemples

Identifying wave and turbulence components in wind-driven shallow basins

Wind-induced waves play an important role in shallow lake hydro- and sediment dynamics. That is why field measurements are important for the validation of their estimation methods, especially in shallow waters. In the first part of the present paper a method is introduced to improve the interpretation of the measured data, applicable both for pressure and velocity data. Replacing the turbulence-affected tail of the measured spectrum with a fitted power function causes a considerable 8-10% difference in the derived bulk wave parameters so this procedure is worth to be done. In the second part an appropriate technique to obtain wave features from 3D velocity time series will be described. The applicability of the presented velocity-based estimation method will be proved by the analysis of field measurements. By velocity decomposition used for the reconstruction of wave features one could also analyse the depth-related differences in the turbulence accompanying the wave motion