Gdaliy Rivin

Polar mesocyclones are often the cause of sudden worsening of weather conditions, including strong winds, snowfall with low visibility, and storms. The short lifetime, rapid development, high movement speeds, and small sizes, combined with a lack of meteorological observations over the Arctic seas, create difficulties in forecasting associated weather phenomena. High-resolution numerical modeling can help address this issue. The emergence and development of polar lows (PLs) significantly depend on the properties of the underlying surface, which largely determine the dynamic properties of the atmosphere in the boundary layer. This article is dedicated to assessing the sensitivity of the configuration ICON-Ru of the model ICON with a 2.0 km grid spacing to changes in the sea ice boundary and sea surface temperature (SST) when forecasting the formation and development of PLs. The results showed that the presence of artificial ice in the model almost completely suppresses the development of PLs in cases where the vortex does not have a strong connection with the jet stream. Heating the SST to 278.15 K while simultaneously shifting the ice boundary northward leads to increased thermal instability, rising sensible and latent heat fluxes, and higher CAPE, which enhances PLs, with the degree of enhancement depending on the nature of the vortex formation itself.

A study of surface and columnar atmospheric aerosol and radiative aerosol effects according to the measurements at the Meteorological Observatory of Moscow State University and mesoscale COSMO-ART model in the urban conditions of Moscow megacity has been presented. The observations of columnar aerosol AERONET retrievals, surface PM10, black carbon (BC) mass concentrations were used as well as radiative and meteorological datasets. We found a positive significant dependence of total and fine aerosol optical depth (AOD) mode (R²∼0.4) with PM10 concentrations with a pronounced bifurcation point around PM10=0.05 mgm⁻³. We also showed the dependence of single scattering albedo with the BC/PM10 fraction both in model and experimental datasets, which is more pronounced in model. Radiative effect of aerosol at TOA varies from -20 Wm⁻² to - 1 Wm⁻² with a noticeable decrease (in absolute value) in conditions with high absorbing aerosol. The validation of city aerosol pollution obtained from the COSMO- ART model against the observed dataset demonstrates an agreement in mostly cases. The difference in AOD between urban and background conditions in Moscow and Zvenigorod (Moscow suburb) due to urban effects comprises about 19% of the total AOD.

The lack of meteorological observations at high latitudes and the small size and relatively short lifetime of polar lows (PLs) constitute a problem in the simulation and prediction of these phenomena by numerical models. On the other hand, PLs, which are rapidly developing, can lead to such extreme weather events as stormy waves, strong winds, the icing of ships, and snowfalls with low visibility, which can influence communication along the Arctic seas. This article is devoted to studying the possibility of the numerical simulation and prediction of polar lows by different model configurations and resolutions. The results of the numerical experiments for the Norwegian and Barents seas with grid spacings of 6.5 and 2 km using the ICON-Ru configurations of the ICON (ICOsahedral Nonhydrostatic) model and with a grid spacing of 6.5 km using the COSMO-CLM (Climate Limited-area Modeling) configuration of the COSMO (COnsortium for Small-scale MOdelling) model are presented for the cold season of 2019–2020. All the used model configurations demonstrated the possibility of the realistic simulation of polar lows. The ICON model showed slightly more accurate results for the analyzed cases. The best results showed runs with lead times of less than a day.

Effects of forest fires on regional weather conditions were analyzed for Central and Eastern Siberia after warm and dry weather conditions in summer 2019 using COSMO-Ru (COnsortium for Small-scale MOdeling; Ru—Russia) and COSMO-RuART (ART—Aerosols and Reactive Trace gases) model systems. Four series of numerical experiments were conducted (one control experiment and three forest fire experiments assuming total vegetation destruction within the burned areas) to evaluate possible effects of forest fires on surface albedo and vegetation properties as well as their influence on air chemistry and aerosol concentration in the atmosphere. The modeling results showed significant influence of forest fires on regional weather conditions that occurred over large areas situated even away from burnt regions. Decreased surface albedo and reduced latent heat fluxes due to fire-induced destruction of forest cover lead to higher near-surface air temperature and lower air humidity in both burned and surrounding unburned forest areas. On the other hand, reduced incoming solar radiation due to smoke from forest fire plumes decreased land surface temperatures and increased thermal atmospheric stability resulting in reduced regional precipitation.

The study presents the new system for operational short-range numerical weather prediction with the grid spacing of 1 km for the Moscow region that conside

The COSMO-Ru1Mp prototype of the numerical weather prediction system for the Moscow region with a grid spacing of 1 km and with the included and adapted TERRA_URB parameterization module for the...

The main stages are considered of the process of Roshydromet forecast technologies modernization that started in the 1990s, especially those related to the use of supercomputers for operational numerical weather prediction (NWP) and to the development of supercomputer technologies for NWP with different lead times. Some outcomes of the modernization are presented.

Described is the second stage of the work (2011-2014) on the implementation and development of the COSMO-Ru system of nonhydrostatic short-range weather forecasting (the first stage of the implementation and development of the COSMO-Ru system is described in [7, 8]). Demonstrated is how the research activities and ideas of G.I. Marchuk influenced modern methods for solving the systems of differential equations that describe atmospheric processes (in particular, the version of the Marchuk’s splitting method is used to find the solution of the finite-difference analog of the system of differential equations in the COSMO-Ru model); it is shown how he contributed to the development of the methods of assimilation of meteorological information associated with the use of adjoint equations. Given is a brief description of the COSMO model of the atmosphere and soil active layer, the COSMO-Ru system, and research activities on this system development.