卷 52, 编号 6 (2016)

An analysis of the air-temperature and atmospheric-pressure fields in Western Siberia is performed based on observations in 1976–2014; a comparison of temperature and pressure variability in two temporal intervals, 1976–2005 and 1985–2014, is carried out. The estimation of contributions from such climate-forming factors as radiation and circulation is performed for the same intervals. It is revealed that an increase in the annual mean ground–air temperature in the investigated region of Western Siberia was still taking place in the period of 1985–2014; however, the warming process was less active than in the 1976–2005 period. Winter months play the largest role in decreasing the temperature growth rate; during these months, the warming process was replaced by a cooling one in the second time interval. It is shown that the circulation factors, that is, the mechanisms described by indices of global circulation, played the dominant role in the period from 1985 to 2014.

The statistical regularity in the chaotic dynamics of wind direction is established. The distribution density of the increment in a wind-direction angle is approximated by generalizing the logistic law of distribution. Parameters of the approximation function are calculated by the least square method using the experimental data. The conformity between the function proposed and the meteorological data is verified by the Pearson’s chi-squared test and the Kolmogorov test.

The possibility of estimating the parameters of surface pulsed sources from data on acoustic waves recorded in the atmosphere is studied. Experimental values are given for peak pressure P₊ of recorded acoustic signals, wave-profile area S₊ in their positive phase, and length t₊ of this phase, and the approximations of these parameters are obtained within wide ranges of source energy 10^–3 < E < 10¹⁰ kg TNT and scaled distances 1 < R/E^1/3 < 4 × 10⁴ m/kg^1/3. Conventional methods of estimating the acoustic energy E according to data obtained from acoustic measurements in the atmosphere are analyzed, and ways to improve their accuracy are proposed. The influence of the type of explosions on the parameters P₊, S₊, and t₊ of acoustic signals at long distances R/E^1/3 > 500 m/kg^1/3 from explosions is shown.

The retrieval of profiles of meteorological variables from radio occultation observations requires knowledge of bending angle profiles up to heights of no less than 60–70 km. Because of the residual error of the ionospheric correction, retrieved profiles become too noisy by a height of about 40 km. In order to invert the bending angle profiles, the statistical optimization is used. This makes it possible to construct an optimal linear combination of the a priori estimate of the average bending angle profile and a posteriori noisy estimate based on observations. The estimate of the average bending angle profile for the given coordinates and the time of year is usually based on the climatological atmospheric model. MSIS and CIRA models that have been used for this purpose are now obsolete and do not describe the global changes in the atmospheric state. The model of average bending angles BA–IAP (Bending Angle–Institute of Atmospheric Physics) is built based on the processing of the array of COSMIC radio occultation observations during 2006–2013. The proposed model is statistically validated based on the COSMIC database. It is shown that our model describes the average bending angle profiles more accurately than the MSIS model.

A method to register sea-wave spectra using optical aerospace imagery has been developed. The method is based on the use of retrieval operators both in areas of high and low spatial frequencies, including the areas of spectral maximum. The approach to adjust and validate the method developed using sea truth data obtained by string wave recorders has been suggested. This paper presents the results of using the suggested method to study sea-wave spectra using high-resolution satellite imagery for various water areas under different conditions of wave generation.

The estimated characteristics of the atmospheric boundary layer, obtained by the simulation of wind wave fields using three versions of the WAM numerical model are compared with the well-known empirical dependences of drag coefficient C_d on wind speed U₁₀ and wave age A, as well as with the dependence of dimensionless roughness height z_n on inverse wave age u*/ср. Calculations carried out for several years in the areas of the Pacific and Indian oceans, based on the ERA-interim and CFSR wind reanalyses have shown good agreement between the model and empirical dependences C_d(U₁₀) and C_d(A). The range of estimated variability for z_n(u*/с_р) has been found to be significantly less than empirical. It has been also found that estimated values of wind speed U_10W(t) are overestimated from 5 to 10% in all versions of WAM models compared with the input wind reanalysis U_10R(t) at the moments of appearance maximum values of wind U_10R(t). The reasons for the established features of the WAM model and their dependence on the model version are discussed.