Nikolay Miloshev

Contribution of biogenic emissions to the atmospheric composition of the Balkan Region and Bulgaria

The present work aims at studying the local to regional atmospheric pollution transport and transformation processes over the Balkan Peninsula and Bulgaria. The US EPA models-3 system is chosen as a modelling tool. As the NCEP global analysis data with one degree resolution is used as meteorological background, the models nesting capabilities are applied for downscaling the simulations to a 9 km resolution over Balkans and 3 km over Bulgaria. The TNO emission inventory is used as emission input. Special pre-processing procedures are created for introducing temporal profiles and speciation of the emissions. The study is based on a large number of numerical simulations carried out for two emission scenarios – with all the emissions and with biogenic emissions excluded. Some results from both emission scenarios which make it possible to evaluate the contribution of biogenic emissions are demonstrated in the paper.

On a new approach for finding the non-steady state kinetic rate of phase formation

Abstract In this study an expression is obtained for the non-steady state kinetic rate of phase formation by using elements of the probability theory. Its most important feature is that it is valid for various cluster sizes larger or equal to the critical (nucleus) size. The results from this expression are compared with the numerical solution of the basic kinetic equation of phase formation, known as Zeldovichs equation, and the coincidence is remarkable. Owing to its greater simplicity, the expression proposed here can be used instead of the numerical solution in a large number of cases. It is shown that some known expressions for the non-steady state kinetic rate valid for nucleus sizes can be used for various larger sizes when the induction period τ k can be determined for these sizes with sufficient accuracy. It is shown that these known expressions for nucleus size, as well as for larger sizes are less accurate than the expression proposed in this paper in view of closeness to the numerical solution.

Climate change impact assessment of air pollution levels in bulgaria

The presented work is aiming at climate change impacts and vulnerability assessment in Bulgaria Climate change may affect exposures to air pollutants by affecting weather and thereby local and regional pollution concentrations Local weather patterns influence atmospheric chemical reactions and can also affect atmospheric transport and deposition processes. US EPA Models-3 System for a region with resolution of 10 km covering Bulgaria is exploited here The meteorological background is produced by the climatic version of ALADIN weather forecast system TNO emission inventory for 2000 is used The chemical boundary conditions are extracted from 50-km resolution runs over Europe made in Aristotle University of Thessaloniki, Greece Calculations for the period 1991-2000 are performed, results presented in a study For year 2000, some scenarios are run, results compared with measured data.

Analysis of the Processes Which Form the Air Pollution Pattern over Bulgaria

The air pollution transport is subject to different scale phenomena, each characterized by specific atmospheric dynamics mechanisms, chemical transformations, typical time scales etc. The air pollution pattern is formed as a result of interaction of different processes. The present study attempts to make some evaluations of the contribution of different processes to the local to regional pollution over Bulgaria. The US EPA Model-3 system is chosen as a modelling tool. As the NCEP Global Analysis Data with one degree resolution is used as meteorological background, the MM5 and CMAQ nesting capabilities are applied for downscaling the simulations to a 3 km resolution over Bulgaria.

Some Basic Facts About the Atmospheric Composition in Bulgaria – Grid Computing Simulations

The present work aims at studying the local to regional atmospheric pollution transport and transformation processes over Bulgaria and at tracking and characterizing the main pathways and processes that lead to atmospheric composition formation in the region.

Nonstationary homogeneous nucleation in the atmosphere — a numerical solution

Abstract The present study deals with the problem of nonsteadiness of the formation process of a new phase in the atmosphere. Using a numerical method, the solution of the main kinetic equation of phase formation is found in the cases of nonstationary homogeneous condensation, deposition and freezing. The results obtained are compared with those derived by the analytical approach, and the advantages of the numerical solution are stressed. The differences between the time characteristics of the nonstationary phase formation process, delay time τ n , transient time t n , effective time lag θ n and induction time or time lag τ are pointed out. The period of nonsteadiness is shown as being essential in the process of formation of a new phase in the atmosphere, which has to be thoroughly studied. It is emphasised that the numerical approach is also applicable to over-critical sizes, i.e. it is applicable in order to obtain the description of the process of condensational growth leading to the formation of visible clusters under experimental conditions. This provides a possibility for immediate comparison between theory and experiment.

Computer Simulations of Atmospheric Composition in Urban Areas. Some Results for the City of Sofia

Some extensive numerical simulations of the atmospheric composition fields in the city of Sofia have been recently performed. An ensemble, comprehensive enough as to provide statistically reliable assessment of the atmospheric composition climate of Sofia—typical and extreme features of the special/temporal behavior, annual means and seasonal variations, etc. has been constructed. The simulations were carried out using the American Environment Protection Agency (US EPA) Models-3 system. As the National Centers for Environmental Prediction (NCEP) Global Analysis Data with 1 degree resolution was used as meteorological background, the system nesting capabilities were applied for downscaling the simulations to a 1 km resolution over Sofia. The national emission inventory was used as an emission input for Bulgaria, while outside the country the emissions were taken from the Netherlands Organization for Applied Scientific research (TNO) inventory. Special pre-processing procedures are created for introducing temporal profiles and speciation of the emissions. The biogenic emissions of Volatile Organic Compound (VOC) are estimated by the model Sparse Matrix Operator Kernel Emissions (SMOKE). The air pollution pattern is formed as a result of interaction of different processes, so knowing the contribution of each for different meteorological conditions and given emission spatial configuration and temporal behavior could be interesting. Different characteristics of the numerically obtained concentration fields of pollutants as well as of determining the contribution of different types of pollutants and pollution sources will be demonstrated in the present paper.

Empirical background model of total ozone density over Bulgaria

A detailed analysis of the variations of the stratospheric and mesospheric ozone over Bulgaria, in the period 1996 to 2012, is presented in the article on the basis of ground and satellite measurements of the total ozone column (TOC). The dynamics of the most important components has been studied. Their mean values for the period and the existing long-term trends have been found. The time evolution of the most basic components of the seasonal course has been studied, including the existing long-term trends and their relations to the stratospheric temperature and quasi-biennial oscillation. Based on these studies and analyses, an empirical model for a daily forecast of TOC over Bulgaria has been created. The main aim of the model is monitoring of the ozone layer and, respectively, the biologically harmful ultraviolet radiation of the sun related to it which has an effect on human health and life.

Risk Analysis and Emergency Forecast of Toxic Substances Local Scale Transport Over Bulgaria

The present paper describes the some results of the modelling system for operational response to accidental releases of harmful gases in the atmosphere (as a result of terrorist attack or industrial accident). The system is based on the following models: WRF, used as meteorological pre-processor; SMOKE – the emission pre-processor; CMAQ – the Chemical Transport Model (CTM) of the system. For the needs of the emergency response preparedness mode the risk is defined as probability the national regulatory threshold values for toxic gases to be exceeded. Maps of the risk around potential sources of emergency toxic gas releases are constructed and demonstrated in the present paper. Some examples of the system “operational mode” results are demonstrated as well.

HPC Simulations of the Fine Particulate Matter Climate of Bulgaria

Some extensive numerical simulations of the atmospheric composition fields in Bulgaria have been recently performed. The US EPA Model-3 system was chosen as a modelling tool. The TNO emission inventory was used as emission input. Special pre-processing procedures are created for introducing temporal profiles and speciation of the emissions. The biogenic emissions of VOC are estimated by the model SMOKE. The numerical experiments have been carried out for different emission scenarios, which makes it possible the contribution of emissions from different source categories to be evaluated. The simulations aimed at constructing of ensemble, comprehensive enough as to provide statistically reliable assessment of the atmospheric composition climate of Bulgaria - typical and extreme features of the special/temporal behavior, annual means and seasonal variations, etc. The present one focuses on the results about fine particulate matter. This is a compound with significant impact on human health, so the interest towards it is recently very big.