Priobalna interakcija atmosfere i mora u uslovima izranjanja

In order to examine a possible sea-air interaction in the vicinity of the western edges of continents, successive integrations of a 2 – D atmosphere and ocean models were performed. The ocean model had prescribed wind forcing that was obtained from the atmospheric model which in turn had prescribed sea surface temperature resembling one for well developed upwelling. Both models are for a hydrostatic and Boussinesq fluid with a sigma coordinate system. They have high resolution in the horizontal and a very high resolution in the vertical, capable of resolving both top and bottom boundary layers. Turbulent fluxes and mixing coefficients are parameterized with the so-called 2.5 level, second order closure scheme proposed by Mellor and Yamada. Seaward boundary conditions for the ocean model and lateral boundary conditions for the atmosphere model were of the radiation type. The ocean model had prescribed sea surface elevation and y-component of the pressure (buoyancy) field from the available data. The diurnal cycle for the atmosphere model was implemented through the specification of the land surface temperature while night time cooling was modelled with a Newtonian forcing. The reference thermodynamic state of the atmosphere model was very similar to the observed state of the atmosphere in the Coastal Ocean Dynamics Experiment while environmental winds were specified to give values for the wind-stress close to the observed climatological values. The significant modification of the wind-stress profile relative to the wind-stress profile for the homogeneous sea surface temperature was obtained when the sea surface temperature was similar to the one for the well-developed upwelling. In the case of the constant sea surface temperature wind-stress profile was fairly constant in the offshore-onshore direction except in the vicinity of the coast line. With sea surface temperature profile resembling well-developed upwelling the atmosphere model developed wind-stress profile that had pronounced decrease in 40 km band next to the coast and a weak increase right at the coast. The ocean model forced with the wind stress obtained from the atmosphere run that had homogeneous sea surface temperature, developed strong upwelling zone and quite strong equatorward current with embedded jet near the coast. Forced with the wind stress from the run with nonhomoheneous sea surface temperature, the ocean run had a much weaker upwelling and a double structure of the longshore current with the poleward flow in the vicinity of the coast line an equatorward flow in the region, away from the coast, where wind stress was bigger than the prescribed, vertically integrad y-component of the pressure gradient force

ASH DUST CONCENTRATION IN THE VICINITY OF THE ASH DISPOSAL SITE DEPENDING ON THE SIZE OF THE POND

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Ash dust co-centration in the vicinity of the ash disposal site depending on the size of the pond (“Water Mirror”)

Thermal power plants Nikola Tesla “A” and “B” are large sources of ash from their ashes/slag deposit sites. Total sizes of ashes/slag depots are 600ha and 382ha, with active cassettes having dimensions ∼200 ha and ∼130 ha. The active cassettes of the disposal sites are covered by rather large waste ponds, the sizes of vary depending on the working condition of a sluice system and on meteorological conditions. Modeling of ash lifting was attempted using results from the dust lifting research. The relation between sizes of ponds and air dust concentration in the vicinity of ash disposal sites was analyzed. As expected, greater sizes of dried disposal site surfaces in combination with stronger winds gave greater dust emission and greater air dust concentration

Method for efficient prevention of gravity wave decoupling on rectangular semi-staggered grids

Generation of short gravity wave noise often occurs on semi-staggered rectangular grids as a result of sub-grid decoupling when there is a strong forcing in the mass field. In this study a numerical scheme has been proposed to prevent the generation of the gravity wave decoupling. The proposed numerical method provides efficient communication between decoupled gravity wave finite-difference solutions by a simple averaging of a term in the height tendency in the continuity equation. The proposed method is tested using a shallow water sink model developed for the purpose of this study. It has been demonstrated that this method outperforms other existing approaches. The new scheme is time efficient, based on explicit time integration and can be easily implemented. The proposed method is applicable in hydrodynamic models specified on semi-staggered B or E grids