Vol 43, No 3 (2018)

This paper describes the impact of altered land use on urban flooding in Northwest Indiana over a 10-year time span between 1992 and 2001. The studied watershed, the Great Calumet basin, is located on the south shore of Lake Michigan, which is well known as a highly industrialized area. The flood peaks and the time-to-peak values are used to analyze the flooding problems of the study area. The study uses a Hydrologic Engineering Center for Hydrologic Modeling System (HEC-HMS) model to explore the change in land use represented by Curve Number (CN). The model parameters are calibrated using archived raintall data available in National Climatic Data Center (NCDC) and United States Geological Survey (USGS) Instantaneous Data Archive (IDA). All four simulations show that the peak flow of simulated hydrographs in the terrain conditions of 2001 is by 22% higher than that in the terrain of 1992. The paper concludes with the results of simulation analyses that can be used to remedy flooding problems in the study area.

The actinometric system installed aboard the Yak-42D "Roshydromet" research aircraft is presented. It is designed to study radiation processes in the troposphere. The system is based on standard Kipp&Zonen actinometric instruments for measuring solar, thermal, and ultraviolet radiation fluxes as well as on specially developed radiation models with high-precision methods for solving radiative transfer equations (Monte Carlo, k-distribution, and line-by-line calculations). The combination of actinometric measurements and detailed simulation of radiative transfer in the atmosphere allows examining the radiation balance components throughout the troposphere using in situ measurements at the aircraft location. Some results of studying radiation fluxes obtained during the flights over the Arctic region of the Russian Federation are presented. The data of measurements carried out using the presented system are useful for validating radiation codes utilized in general atmospheric circulation models and for processing satellite remote sensing data.

In the first half of the 1930s A.N. Kolmogorov was developing analytical methods for the probability theory and presented the solution of the Fokker–Planck type equation. This solution contains scales for the distribution function moments of the mean squares for velocities and relative displacements of the analyzed objects and for the mixed moments of velocities and coordinates. The exclusion of time from these moments leads to the 2/3 law for the velocity structure function and to the Richardson–Obukhov law for the eddy diffusion. The analysis of the fetch laws for wind waves demonstrates that the Kolmogorov laws are manifested in the growth of wave amplitudes and in the form of elevation spectra. These laws also work in the statistics of the planetary surface relief, in the size distribution of the lithospheric plates, in the energy spectra of cosmic rays, and in other processes. In the equation deduced in 1934, probability distribution functions are derived only under the condition of homogeneity of these functions and thereby allow describing a broad range of phenomena and processes.

Radiosonde data are used for the period of 1964–2014 and the method that determines the boundaries and cloud amount based on the profiles of temperature and humidity [23]; long-period statistical characteristics are computed for the cloud layer number for different altitude ranges from the ground to 10 km. The study is performed for the Russian aerological stations located at different latitudes and climate zones. To specify the spatiotemporal features of the atmosphere layering into cloud layers and cloudless layers between them, the estimates of monthly mean, seasonal mean, and annual mean values of cloud layer number as well as of their standard deviations are computed, and the amplitude of their variations is determined. The results qualitatively agree with the data of aircraft-based sounding of the atmosphere as well as with the data of radars and experiments with free balloons.

The results of lidar measurements of ozone profiles over Obninsk in the altitude range of 12–35 km in 2012–2016 are presented. Temporal variations in total ozone in the above altitude range and seasonal variations in the vertical distribution of ozone are considered. Basic attention is paid to the analysis of ozone profile variations on the daily and weekly scales. The backtrajectory analysis demonstrated that in most cases the formation of layers with low or high ozone values is explained by the direction of meridional advection. Cross-correlation coefficients for the variations in ozone and temperature relative to the current monthly mean variations are calculated. Rather high values of correlation coefficients (~0.4–0.6) are obtained for summer in the low stratosphere (100 and 160 hPa) and for winter in the upper troposphere (50 and 20 hPa). In general, variations in ozone profiles are consistent with available climatologic data.

The wave drag is considered for downslope windstorms in Novorossiysk, on Novaya Zemlya, and in Pevek. The research is based on the results of numerical simulation with the WRF-ARW model. Special attention is paid to the evaluation of the contribution that wave processes make to the overall dynamics of the phenomenon (based on the ratio of wave and orographic drag) and to the specific features of wave drag for different downslope windstorms.

The quality of Arctic winter stratospheric dynamics forecast using the SL-AV atmospheric global circulation model is studied. The series of numerical experiments show that forecasts with the lead time up to 7 days are successful. Zonal wind reversal during minor sudden stratospheric warmings is predicted 10–11 days ahead. Overall, the situations of strong polar jet disturbances are beneficial for the forecast accuracy.