Aleksandre Surmava

PM2.5 propagation at Tbilisi city territory in winter period during north background weak wind is modeled and analyzed using 3D regional model of atmospheric process evolution and via combined integration of admixtures transfer and diffusion equations. The motor transport moving at city streets and highways is the main source of atmosphere pollution. Zones of high concentrations of PM2.5 in the city have been established, time intervals have been determined when high air pollution is formed or the process of air self-cleaning proceeds

PM2.5 propagation at Tbilisi city territory in winter period during nortsouth background weak wind is modeled and analyzed using 3D regional model of atmospheric process evolution and via combined integration of admixtures transfer and diffusion equations. The motor transport moving at city streets and highways is the main source of atmosphere pollution. Zones of high concentrations of PM2.5 in the city have been established, time intervals have been determined when high air pollution is formed or the process of air self-cleaning proceeds

Science 2010, aq short-term regional marine forecasting fieldsw -the current, temperature and salinity operaits for the Georgian sector of the Blacr Sea and adjacement sater area.The forecasting sistem is based on the regional model of Black Sea dynamics of the Marine Hydrophysical Institude (Sevastopol)  

The subject of our study is atmospheric air pollution with numerical modeling. In the presented article, as the object of research there is chosen city Tbilisi, the capital of Georgia, with a population of one and a half million and a difficult terrain. Main source of pollution in Tbilisi is currently vehicles and construction dust. The concentrations of dust and PM (Particulate Matter) were determined in the air of Tbilisi and in its vicinity.There are estimated their monthly maximum, minimum and average concentrations. Processes of dust propagation in the atmosphere of the city and its surrounding territory are modelled using 3D regional model of atmospheric processes and an admixture transfer-diffusion equation. There were taken figures of distribution of the polluted cloud and dust concentrations in different areas of the city at different heights and at different time intervals with the background stationary eastern wind. It is accepted that the difficult terrain and mountain-bar circulation affect the deformation of the cloud and its spread, there are determined time periods when the dust concentration in the city is greater than MAC (Maximum Allowable Concentration, MAC=0.5 mg/m3).

The concentrations of PM2.5 and PM10 in the atmospheric air of Tbilisi and the adjacent territory during the COVID-19 pandemic was studied. A decrease of the PM concentrations in the atmosphere of the city was revealed and it was found that the main contribution to the pollution of the atmosphere of Tbilisi with PM2.5 and PM10 is made by motor vehicles. The concentration of PM2.5 in the atmosphere of Tbilisi is usually lower than the concentration of PM10 by about 2-4 times, but the character of the curve of their changes is the same. The maximum dust pollution is reached in the evening hours, after 19:00. At a height of 2 m from the surface layer, the high concentration of PM10 (1.0-2.5 MAC) is formed in the interval from 16:00 to 21:00 in the central and southern parts of the city and on relatively flat areas.

Dust propagation at the territory of Tbilisi city in case of western background light air is studied using the 3D regional model of atmospheric processes and integration of the equation of admixtures’ transfer-diffusion. In this model, the motor transport is considered as a main non-stationary pollution source, from which a dust is emitted into the atmosphere. By numerical modeling there is shown that the process of air pollution by the dust proceeds in four stages and they depend on the intensity of motor traffic, the micro-relief of the city and the location of city mains. In the interval of time 06.00 – 09.00 the intensive growth, 09.00 - 15.00 – a constancy or weak decrease, 18.00 -21.00 a growth, and from 21.00 to 06.00 a reduction of the dust concentrations take place. The highly polluted areas are located in the vicinity of the city center and at some peripherical territories of the city, where the maximum of dust concentration at 21.00 is equal to 2 maximum allowable concentration.

Pollution by PM (particulate matter) of atmospheric air in Tbilisi was studied. Tbilisi is one of the largest cities in the South Caucasus and has a difficult terrain. On the basis of the data of 5 observation points, the hourly dynamics of atmospheric pollution was considered: the maximum, minimum and average values ​​of PM_2.5, PM₁₀ in individual parts of the city were estimated. The values ​​of the statistical characteristic parameters of PM in the atmosphere of Tbilisi are analyzed and trend graphs are constructed. During the analysis of air pollution data, special attention was paid to the period when quarantine was declared in the city. This analysis showed, that the main source of pollution in the city is road transport. Experimental measurements of PM_2.5, PM₁₀ in the atmosphere have been carried out in different districts of the city and map of the distribution of their concentrations were constructed. It is shown that maximum pollution values ​​are recorded in the city center and along major motorways. It is shown that the average monthly concentrations vary in the range of 0.6 – 1.6 Maximum Permissible Concentration (MPC). Average daily values ​​of concentration vary at 2-4 day intervals. The distribution of PM₁₀ generated as a result of traffic is numerical modeled. The modeling results are compared with the observation data.

The concentrations of PM-particles and dust in the air in Tbilisi and its surrounding area are define. Their monthly maximum, minimum and average values ​​are estimated. The dust diffusion process is modeled in the case of background, stationary westerly winds. The source of pollution is dust generated in the city. Visual images of dust distribution area and concentrations are obtained.  

A kinetic of dust distribution in the city of Tbilisi using a 3D regional model of atmospheric processes in

Caucasus and numerical integration of the transport-diffusion equation of the impurity in case of different eastern

background winds are investigated

Based on computational experiment, some of the key features of the circulation processes in the

easternmost waters of the Black Sea and their impact on the spread of oil slick on the sea surface have been studied.

Computational experiments have been conducted on the basis of a coupled modeling system consisting of a regional

model of sea dynamics and a non-stationary advection-diffusion model of the distribution of impurities.

The temporary variations of the dust concentration in Tbilisi city by of the data of natural measurement are investigated and dust propagation at Tbilisi city territory in case of strong background eastern winds by numerical modelling are studied. It is shown that dust propagation substantially depends on both the terrain of city and surrounding territories and on the magnitude and direction of background wind velocity. It is obtained that dust propagation process in case of strong background wind is characterized by time variation and spatial distribution peculiarities. High pollution zones as well as the reasons of their time variation and dust accumulation are determined. It is established that a high pollution level (1.2-2.0 MAC) is obtained in the time interval from 3 p.m. to 9 p.m. in the up to 50 m thick lower part of surface layer of the atmosphere.  

Distribution patterns of dust dissipated in the atmosphere are obtained at different level from the surface. It is shown that dust dissipated from city in the atmosphere is basically concentrated in the boundary layer. Maximum values of dust concentration are obtained in the lower 100 m surface air layer. The influence of local orography on the pollution cloud is investigation. There is identified an area, were urban dust can cause pollution of adjacent environment, as well as the zone and quantity of dust deposited on the ground.

The kinematics of dust concentration change created by motor transport at the territory of Tbilisi and diurnal pattern of its spatial distribution in case of strong background eastern wind are studied. Via analysis of wind velocity and concentration fields it is obtained that spatial distribution of heavily polluted areas depends on city mains disposition, and local circulation systems formed under dynamic impact of terrain and diurnal change of thermal regime at the underlying surface. Maximum concentration 1.5-2.0 MPC is obtained in time interval of t = 15-21 h in the central and western parts of the city. At 600 m height from earth surface a maximum value of concentration reaches 0.7 MAC, when t = 21h. Results obtained through modeling of time and spatial changes of dust concentration qualitatively correctly describe the true picture. From a quantitative viewpoint, modeling results are close to average characteristic data of observations.

The main characteristics of industrial dust diffusion in the industrial region of Georgia, the city of Zestaponi, were studied in the cases of background, weak, and strong western winds. The calculations were carried out using a regional model for the development of atmospheric processes in the Caucasus and the equation for the transfer of passive impurities

A numerical model of the propagation of dust emitted into the atmosphere is based on a three-dimensional nonlinear nonquasistatic equation for thermal convection in the atmosphere. The model uses a digital grid with high resolution capability. The kinetics of the distribution of 10 μm dust particles emitted from two high sources into the atmosphere are studied using numerical modeling. Two meteorological situations are considered - calm and background northwest wind. By modeling, it is obtained that the kinematics of the distribution of dust emitted into the atmosphere are substantially different from each other in the case of quiet and background movement. Spatial dust distribution occurs as a result of both ordered horizontal and vertical flows as well as diffuse movements. Diffusion of advection, convection and turbulent dust under the influence of background wind creates a cloud-shaped vertical zone of dust pollution. No diffusion motion is obtained in the received zone

The kinetics of anthropogenic dust scattering in the atmosphere of large cities by separate sources using numerical integration of a system of three-dimensional nonlinear quasi-static and non-static equations of the atmosphere. It is accepted by modeling that the dust propagation kinematics obtained by quasi-static and non-static equations have both common and different characteristics. In the case of beta-mesoscale diffusion, described by quasistatic equations, advection diffusion plays a major role in the dust transfer process. In the case of gamma-scale diffusion, described by non-static equations, convection diffusion plays a major role in the dust transfer process.   

By numerical integration of the system of three-dimensional non-linear quasi-static and non-static equations of atmospheric hydrothermodynamics the kinetics of dust distribution in the cities of Tbilisi and Kartli region are studied.. 

By using the regional model for the development of atmospheric processes in the Caucasus and the passive impurity transference equation, the diffusion of urban dust is simulated in cases of background, weak and strong west winds. The main characteristics of dust diffusion in the industrial region of Georgia – c.Zestafoni and its environs are studied. Areas of urban dust distribution, the vertical structure of a dust cloud, the surface density of deposited dust, etc. have been determined.

Dust distribution of the industrial town Zestafoni located in the complex territory of Georgia in case of basic meteorological situations and stationary pollution sources is studied with the use of regional model of atmospheric process development in the Caucasus and non-stationary three-dimensional equation of transfer-diffusion of passive admixtures.

Distribution patterns of dust dissipated in the atmosphere are obtained at different level from the surface. It is shown that dust dissipated from cities in the atmosphere is basically concentrated in the boundary layer. Maximum values of dust concentration are obtained in the lower 100 m surface air layer. Spatial dust distribution region increases and concentration decreases along with height increase. An influence of local orography on the pollution cloud is investigated. During a background western Light Air Likhi and Racha ridges impede dust transfer to the east and cause dust cloud deformation. Dust spreads along the valleys of Kvirila and Chkherimela rivers located between the ridges. In case of Gentle and Fresh Breezes the impact of local orography on the dust dispersion process is insignificant. Dust is basically transferred in the direction of background flows.

The zone of influence of industrial town dust on the environmental pollution is determined. A width of this area varies from 5 to 20 km in dependence of the background wind velocity.

Kinematics of dust propagation is studied. It is determined that in 2-100 m layer of atmosphere the process of turbulent diffusion take precedence in the process of dust spreading. From 100 m to 1 km the processes of diffusive and advective transfers are identical, while above 1 km the preference is given to advective transfer.

Numerically modeled and studied dust distribution in industrial cities of Georgia in case of weak westerly wind. Images of spatial distribution of dust are obtained, the influence of orography, horizontal and vertical turbulence and advection processes on the distribution of dust in the atmosphere is analyzed.

the spatial distribution of meteorological fields in the case of background north wind in the territory of Kakheti by using the model of atmospheric processes in the Caucasus adapted to the regions , has been studied. It is shown that the interaction of the terrain and the background wind generates vertical meridional and zonal meso-scale vortices, local vertical movement zones, and the temperature field characteristic of the region.

Numerical experimental modeling of passive pollutants flowing into the Mtkvari River near the Georgian-Turkish state border was performed. The modeling determined the time it would take for pollutants to reach various points in the settlements, including the Georgian state border and the Mingechauri Reservoir in Azerbaijan. The distribution of pollutant concentrations along the river and the change in these concentrations over time as they move from one section to another were determined. Relative changes in pollutant concentrations over more than 10 conditional river sections were assessed

Based on comparative analyzes, an important role of uncontrolled landfills in ecosystem pollution processes has been identified. It turned out that the impact of landfills on ecosystems in eastern Georgia is much higher than in western Georgia

It is shown, that the relief of the Caucasus significantly influences on the trajectory of the pollution distribution. The North West orientation of the Main Caucasian Range resists air motion to the north, constrains the radioactive pollution in the boundary layer to flow around the Main Caucasian Range from the west or east sides. It is obtained that the 48 hours are necessary for the radioactive cloud to overflow the South Caucasus and distribute over the territory of the North Caucasus. The radioactive pollution is falling out mainly in the central, southeast and northwest parts of the South Caucasus. The zone of the radioactive deposition is extended along the background wind and deformed by the influence of the relief. The maximum length of the zone of significant deposition of radioactive substance equals approximately 750 km in case of the background South East wind and 350 km in other cases. The maximum width of the zone approximately equals 150 km. It is obtained that the surface density of the deposited radioactive nuclide in the zone of significant radioactivity decreases from 360 a.u./m² down to 1 a.u./m² when the concentration of 10 aerosol 131I in emission plume during during 6 hours are equal to 100 a.u./m3.

The distribution of the pollution substances emitted in the atmosphere in result of the hypothetical accidents in the industrial centers located on the Great Silk Road’s Caucasian interval - in the t. Poti, t. Baku and t. Metsamor by numerical modeling are investigated. The possible trajectories of the pollution substances displacements in case of the different background winds by calculations are determined. It is shown the relief of the Caucasian Region significantly changes the trajectory of pollution cloud

In the paper the prognostic hydrophysical fields corresponding to the cold season for 2010-2014, which are calculated for the easternmost part of the Black Sea on the basis of the regional forecasting system of the Black Sea state, are analyzed. The analysis of the received results shows that the character of the regional circulation processes for cold season substantially differs from circulation characteristic for the warm period. The Batumi anticyclonic eddy typical for the warm period to a lesser degree or practically is not observed in the cold period and nonstationary processes of generation, evolution and dissipation of cyclonic and anticyclonic eddies of different sizes permanently take place. 

By means of regional model of development of atmospheric processes in the Caucasian Region and the equation of a substance transfer the spatial distributions of zones of radioactive deposition are investigated. In the model the radioactive decay and aerosols deposition processes are taken into account. The distribution of radioactive pollution is simulated in cases of the South, South West and South East background winds. The distribution of only one radionuclide aerosol 131I with diameter 10 µ m is considered. Numerical simulation shows that the 48 hours are necessary for the radioactive cloud to overflow the South Caucasus and distribute over the territory of the North Caucasus. The radioactive pollution is falling out mainly in the central, southeast and northwest parts of the South Caucasus. The zone of the radioactive deposition is extended along the background wind and deformed by the influence of the relief. The maximum length of the zone of significant deposition of radioactive substance equals approximately 750 km in case of the background South East wind and 350 km in other cases. The maximum width of the zone approximately equals 150 km. It is obtained that the surface density of the deposited radioactive nuclide in the zone of significant radioactivity decreases from 360 a.u./m2 down to 1 a.u./m2 when the concentration of 10 µ m aerosol 131I in emission plume during 6 hours are equal to 100 a.u./m3

.

The possible distribution of the contaminants emited in the Caucasus atmosphere by numerical modelling is investigated. 

By meansw of equation of filtration and equation of Kinetics for chemical reaqtion of a carbonate sodiumand calciun sulfate a change of the ground salinity is numericalyly simulated. It is shown, the application of sorbent intensifies reduction of the content of sodium in 5 m layer of soil. tThe content of sodiun especially strongly decreases in the top 40 cm layer of soil. In greater depths a reduction on the content of sodium occurs considerably slowly. 

By numerical modeling the distribution of radioactive cloud in the atmosphere of Poti and its surroundings in different meteorological conditions are studied.

By use the Numerical modeling is shon thathas shown that frequent watering significantly reduces the salinity of the topsoil (70 cm).

Variability of soil salinity in different meteorological and irrigation conditions has been studied using numerical modeling for arable and saline soils of Georgia.

Doctoral Thesis Referee

Master Theses Supervisor

Doctoral Thesis Supervisor/Co-supervisor

Scientific editor of monographs in foreign languages

Scientific editor of a monograph in Georgian

Editor-in-Chief of a peer-reviewed or professional journal / proceedings

Review of a scientific professional journal / proceedings

Member of the editorial board of a peer-reviewed scientific or professional journal / proceedings

Participation in a project / grant funded by an international organization

Participation in a project / grant funded from the state budget

Patent authorship

Membership of the Georgian National Academy of Science or Georgian Academy of Agricultural Sciences

Membership of an international professional organization

Membership of the Conference Organizing / Program Committee

National Award / Sectoral Award, Order, Medal, etc.

Honorary title

Monograph

Handbook

Research articles in high impact factor and local Scientific Journals

Publication in Scientific Conference Proceedings Indexed in Web of Science and Scopus