Alexander V. Starchenko

Numerical Modelling of Pollutant Propagation in Lake Baikal during the Spring Thermal Bar

Abstract In this paper, the phenomenon of the thermal bar in Lake Baikal and the propagation of pollutants from the Selenga River are studied with a nonhydrostatic mathematical model. An unsteady flow is simulated by solving numerically a system of thermal convection equations in the Boussinesq approximation using second-order implicit difference schemes in both space and time. To calculate the velocity and pressure fields in the model, an original procedure for buoyant flows, SIMPLED, which is a modification of the well-known Patankar and Spaldings SIMPLE algorithm, has been developed. The simulation results have shown that the thermal bar plays a key role in propagation of pollution in the area of Selenga River inflow into Lake Baikal.

To the selection of heat flux parameterization models at the water-air interface for the study of the spring thermal bar in a deep lake

The paper is devoted to the comparative analysis of the parameterization models of latent and sensible heat fluxes, longwave radiation calculated on the basis of the papers of Goudsmit G.-H. et al. (2002), Hodges B. (1998), Ji Zh.-G. (2008) with the use of atmospheric data of the meteorological station of City of Kamloops (Canada) within the period from 01.04.2001 to 10.05.2001. Numerical analysis of the distribution of spring thermal bar in Kamloops Lake was carried out with mathematical simulation methods.

Forecast of precipitation in the area of Bogashevo airport using the WRF model

Numerical simulation results obtained for meteorological conditions in the area of Bogashevo airport and the city of Tomsk using the Weather Research & Forecasting (WRF) mesoscale system are presented. The main attention is paid to choosing the parameterization of microphysical processes adequate for conditions of Western Siberia with the aim to obtain a reliable forecast of intense rainfalls. The performed comparison of predicted and factual data on precipitation and cloudiness demonstrated good possibilities of the model for forecasting precipitation and dangerous events for aviation. The ETA microphysics parameterization yielded the best results.

Simulation of turbulent transport during 24-hour evolution of the atmospheric boundary layer

This paper aims to select an accurate and numerically efficient second-order closure model of turbulence to predict dispersion of pollution in the atmospheric boundary layer. An one-equation E-model suggested by Mellor and Yamada, two- equation E-(epsilon) model by Duynkerke and E-1 model with algebraic relations for Reynolds stresses and turbulent fluxes for conditions of 33 - 34 days of the Wangara experiment are compared. Ii is shown that the later model more accurately predicts data of observation but it needs more computational time.

Simulation of Doppler lidar measurements using the WRF and Yamada-Mellor models

In this paper the numerical simulation results of mean wind velocity vector and its measurement error for VAD technique using Weather Research and Forecasting Model (WRF) and Yamada-Mellor models are presented. The numerical model takes into account the non-Gaussian and nonstationary characteristics of the Doppler lidar signal. The numerical simulation results were compared with CASES-99 experimental data from balloon sonde (GLASS) and the Doppler Lidar. It shows that results of numerical simulation by WRF and Yamada-Mellor models agree well with experimental data for potential temperature. Yamada-Mellor model describes the nocturnal low-level jet only up to 100 m and above the fit is fairly bad. But WRF model allows us to have a good comparison for all levels. In case of the strong turbulence the value of measurement error can greatly surpass the value 0.5 m/s; therefore it does not satisfy World Meteorological Organization (WMO) requirements for wind. For the high spatial resolution we cannot get the required accuracy.

A model of short-range forecast of homogeneous atmospheric boundary layer parameters in view of solving the problems of laser beam propagation in the atmosphere

The paper suggests a model for predicting the behavior of the optical characteristics of a medium that determine the character of laser beam propagation in the atmosphere. These are first of all the refractive index and the refractive-index-structure parameter as well as the wind velocity, kinetic turbulence energy, dissipation energy speed and other meteorological parameters that are important in the laser propagation problem. The prediction of the refractive index and the refractive-indexstructure parameter is based on the known equations of the theory of wave propagation in a turbulent atmosphere and a mathematical model for short-range forecast of evolution of local meteorology and turbulent structure of the atmospheric boundary layer (ABL).

The effects of wind and diurnal variability of surface heat fluxes on riverine thermal bar dynamics: a numerical experiment

ABSTRACT We numerically reproduced the spring riverine thermal bar in the area of the Selenga inflow into Lake Baikal using the nonhydrostatic 2.5D mathematical model. Our model took into account the diurnal variability of the heat fluxes and wind stress on the lake surface based on the atmospheric data from the Babushkin weather station archive during 1–30 May 2015. Propagation of the thermal bar is driven principally by the mechanical and thermal energy of the river inflow together with shortwave radiation while longwave radiation and latent and sensible heat fluxes make smaller contributions. Numerical modeling of the lake hydrodynamics demonstrated that the thermal bar propagation decelerated at night and that strong reverse motion of the thermal bar (toward the shore) was possible within some specific areas due to night cooling and opposing wind. These effects appear following an initial period in which the dynamics are dominated by the river inflow. As the distance from the mouth of the Selenga to the thermal bar increased, the impact of westerly winds on the reverse movement of the thermal bar was reinforced, although the influence of wind does not extend to the full depth of the lake.

Parallel Algorithms for a 3D Photochemical Model of Pollutant Transport in the Atmosphere

In this paper, a numerical scheme for solving a system of convection-diffusion-kinetics equations of a mathematical model of transport of small pollutant components with their chemical interactions in the atmospheric boundary layer is presented. A new monotonized high-accuracy spline scheme is proposed to approximate the convective terms. Various approaches to parallelization of the computational algorithm are developed and tested. These are based on a two-dimensional decomposition of the calculation domain with synchronous or asynchronous interprocessor data communications for distributed memory computer systems.

Forecast of icing zones using possibilities of hydrodynamic simulation for the atmospheric boundary layer

This paper presents the results of the analysis and forecast of meteorological conditions that promote icing of aircrafts in the atmospheric boundary layer. The forecasting results were obtained using the mesoscale meteorological model TSU-NM3. The Godske method, the NCEP method, and the statistical method of the Hydro-meteorological Centre of Russia were used as the criteria of aircraft icing probability during take-off or landing. The numeric forecast results were compared with pilot reports. The forecast accuracy rates, the probability of false detection, and the Peirces skill score confirm the prospects of the proposed approach for the sphere of forecasting aircraft icing zones. On the basis of this technology, a regional method for forecasting aircraft icing can be developed.

Meteorological optical range predictability with the use of high resolution mesoscale models

The report describes and argues in favor of the data base for numerical experiments with hydrodynamic and photochemical atmospheric models with the purpose of the meteorological visibility forecast. The obtained results demonstrate methodological potential of this approach.