Transporting passive additives in a turbulent medium under convective mixing     

V. P. Kukharets  O. G. Nalbandyan  A. V. Shmakov 《Izvestiya Atmospheric and Oceanic Physics》2009,45(4):411-415

The vertical transport of passive additives in a medium in the presence of both turbulent and convective mixing is studied. It is shown that, despite the fact that turbulent and convective fluxes are uncorrelated, no additive mechanism of mixing exists. On the basis of a theoretical model and a comparison with model calculations, it is shown that, in the presence of both turbulent and convective mixing in a medium, the effect of the interference of turbulent and convective transport mechanisms takes place. This effect is manifested in the following way: the presence of convection decreases the coefficient of turbulent transport and the presence of turbulence decreases the coefficient of convective transport; in this case, this effect depends on the parameter of the inhomogeneity (extension) of convective fluxes. The relative contribution of each of the mechanisms to the total transport is estimated. It is shown that the interference of turbulence and convection results in an anisotropy of the coefficient of turbulent transport in an isotropic turbulent velocity field. The effect of the coefficient of molecular diffusion is assumed to be negligibly small, and its effect is not taken into consideration when analyzing model results. The interference of the turbulent and convective mechanisms of transport is explained by the inclusion of an additional mechanism that decreases the distance of linear particle propagation.  相似文献   

Reconstruction of the Internal-Wave Parameters in the Atmosphere from Signal Amplitude Fluctuations in a Radio-Occultation Experiment     

Kan  V.  Gorbunov  M. E.  Shmakov  A. V.  Sofieva  V. F. 《Izvestiya Atmospheric and Oceanic Physics》2020,56(5):435-447

Izvestiya, Atmospheric and Oceanic Physics - In this paper, we discuss a method for reconstructing the parameters of internal gravitational waves (IGWs) in the stratosphere from amplitude...  相似文献   

Ways of investigating radionuclide migration processes in the lithosphere and hydrosphere     

A. P. Belousova  A. I. Shmakov  O. V. Galaktionova 《Environmental Geology》1994,24(4):306-308

In Russia, until recently, it was considered that groundwater was protected from surface radioactive contamination by soil and rocks in the zone aeration. Groundwater was not a subject of radiation control. The accident at the Chernobyl Nuclear Power Plant showed, however, that groundwater is vulnerable to radioactive contamination. In this connection, the vulnerability of groundwater to and the problems of protecting groundwater from radioactive contamination became urgent. The assessment of natural protection of groundwater from radioactive contamination is now considered a top priority. The zone of aeration is generally considered to be the zone separating groundwater from surface contamination. In respect to radioactive contamination, soils that may fix a large quantity of radionuclides serve as a protection zone of a higher order. The mapping of protectibility was done for each radionuclide taking into consideration the specific structure of the flow medium and migration properties of a radionuclide.⁹⁰Sr and¹³⁷Cs have different mechanisms of transport; convective transport is characteristic of the former and diffusive transfer of the latter. This is conditioned by different physico-chemical properties of the radionuclides and principally by their sorption capacities. The coefficient of distribution of⁹⁰Sr is in many times less than the coefficient of distribution of¹³⁷Cs. The environmental protection problem in regions with nuclear power plants and in areas subjected to radioactive contamination may be solved using a monitoring, system including interrelated systems of observation and prediction of the lithosphere and the hydrosphere. The problem of mathematical modeling of migration processes is related to the complexities of modeling the processes of flow, mass transfer, and the accompanying physicochemical processes in zones of full and partial saturation, as well as difficulties in mathematical calculations.  相似文献   

Statistically average atmospheric bending angle model based on COSMIC experimental data     

M. E. Gorbunov  A. V. Shmakov 《Izvestiya Atmospheric and Oceanic Physics》2016,52(6):622-628

The retrieval of profiles of meteorological variables from radio occultation observations requires knowledge of bending angle profiles up to heights of no less than 60–70 km. Because of the residual error of the ionospheric correction, retrieved profiles become too noisy by a height of about 40 km. In order to invert the bending angle profiles, the statistical optimization is used. This makes it possible to construct an optimal linear combination of the a priori estimate of the average bending angle profile and a posteriori noisy estimate based on observations. The estimate of the average bending angle profile for the given coordinates and the time of year is usually based on the climatological atmospheric model. MSIS and CIRA models that have been used for this purpose are now obsolete and do not describe the global changes in the atmospheric state. The model of average bending angles BA–IAP (Bending Angle–Institute of Atmospheric Physics) is built based on the processing of the array of COSMIC radio occultation observations during 2006–2013. The proposed model is statistically validated based on the COSMIC database. It is shown that our model describes the average bending angle profiles more accurately than the MSIS model.  相似文献