Reconstruction of internal gravity wave parameters from radio occultation retrievals of vertical temperature profiles in the Earth's atmosphere

A new method for the reconstruction of internal gravity wave (IGW) parameters from a single vertical temperature profile measurement in the Earth's atmosphere has been developed. This method does not require any additional information not contained in the profile and may be used for the analysis of profiles measured by various techniques. The criterion for the IGW identification has been formulated and argued. In the case when this criterion is satisfied, then analyzed temperature fluctuations can be considered as wave-induced. The method is based on the analysis of relative amplitude thresholds of the temperature wave field and on the linear IGW saturation theory in which amplitude thresholds are restricted by dynamical (shear) instability processes in the atmosphere. When the amplitude of an internal gravity wave reaches the shear instability limit, energy is assumed to be dissipated in such a way that the amplitude is maintained at the instability limit as the wave propagates upwards. In order to approbate the method we have used data of simultaneous high-resolution balloon measurements of the temperature and wind velocity in the Earth's stratosphere over France where a long-period inertia-gravity wave has been detected. Using the radiosonde temperature data only, we have reconstructed all wave parameters, which were determined by radiosondes, with relative deviations not larger than 30%. An application of the method to the radio occultation (RO) data has given the possibility to identify the IGWs in the Earth's stratosphere and to determine the magnitudes of key wave parameters such as the intrinsic frequency, amplitudes of vertical and horizontal perturbations of the wind velocity, vertical and horizontal wavelengths, intrinsic vertical and horizontal phase (and group) speeds, kinetic and potential energy, vertical fluxes of the wave energy and horizontal momentum. The obtained results of internal wave studies in the Earth's stratosphere deduced from the COSMIC and CHAMP GPS occultation temperature profiles are presented and discussed

Exciton and Hole-Transfer Dynamics in Polymer:Fullerene Blends

Ultrafast hole transfer dynamics from fullerene derivative to polymer in bulk heterojunction blends are studied with visible-pump – IR-probe spectroscopy. The hole transfer process is found to occur in 50/300 fs next to the interface, while a longer 15-ps time is attributed to exciton diffusion towards interface in PC71BM domains. High polaron generation efficiency in P3HT blends indicates excellent intercalation between the polymer and the fullerene even at highest PC71BM concentration thereby yielding a valuable information on the blend morphology

Analysis and verification of vertical profile of atmospheric temperature for Kazan area according to radio occultation in satellite-to-satellite communication line

The altitude temperature dependences in the atmosphere, measured in the period from 2007 to 2010 in the area of Kazan by meteorological radiosondes and radio occultation method are compared. Radiosonde measurements of the atmosphere were conducted twice a day at 0 and 12 UTC, i.e. at 4 and 16 h local time. The radio occultation experiments were carried out using radio waves emitted by GPS navigation satellites in the decimeter range and received on low Earth orbit satellites Formosat-3 when they entered the Earth's limb relative to the satellite-transmitter. Despite the fact that the radio occultation method provides about 2,000 atmospheric soundings per day for different regions of the Earth, when analyzing the accuracy in the measurements of the vertical temperature profiles for a particular small climatic region, it is possible to obtain only one radio sounding in two, three days, at an arbitrary local time. When comparing the experimental dependencies, a strict restriction of not more than one hour has been introduced on the difference in the time of meteorological and radio occultation soundings. The distance between the radiosonde and the area of radio sounding of the atmosphere was chosen to be less than 250 km. The data of 43 sessions of the radio occultation soundings of the temperature altitude profiles obtained by two ways in different seasons of the year are given in the altitude range from 0.5 to 25 km were compared. It is shown that under such conditions at altitudes of more than 6 km the difference in the values of the temperature measured by the two methods does not exceed ±2 °C. At low humidity in the winter season, radio occultation and meteorological data at altitudes of 1 to 3 km differed by not more than 4 °C. At altitudes below 4 km the radio occultation method gives an underestimate of the temperature because of the influence of air humidity. The results of determining the vertical temperature gradients in the middle troposphere differ by no more than ±0.6 °C/km, and the height of the tropopause - by ±0.5 km

Скоростная модуляция поперечно-модового состава лазерных пучков с помощью дифракционных оптических элементов на основе LiNbO3

A diffractive optical element based on a nonlinear-optical ferroelectric single crystal has been proposed, synthesized, and experimentally characterized. The element allows fast modulation of transverse modes of a Gaussian laser beam. © 2021, Institution of Russian Academy of Sciences. All rights reserved.The equipment of the Ural Center for Shared Use “Modern nanotechnolo- gy” UrFU was used. This work was supported by the Russian Foundation for Basic Research (grant no. 18-29-20077 mk)

Multi-functional oilfield production chemicals: maleic-based polymers for gas hydrate and corrosion inhibition

Several chemical problems can occur during the production of oil and gas through flow lines. This includes corrosion, scale deposition and gas hydrate plugging. Three separate chemicals may be needed to treat these issues. Kinetic hydrate inhibitors (KHIs) are used in cold oil or natural gas production flow lines to prevent the formation and plugging of the line with gas hydrates. They are often injected concomitantly with other production chemicals such as corrosion and scale inhibitors. KHIs are specific low molecular weight water-soluble polymers with amphiphilic groups formulated with synergists and solvents. However, many corrosion inhibitors (CIs) are antagonistic to the KHI polymer, severely reducing the KHI performance. It would be preferable and economic if the KHI also could act as a CI. We have explored the use of maleic-based copolymers as KHIs as well as their use as film-forming CIs. KHIs were tested using a natural gas mixture in high pressure rocking cells using the slow constant cooling test method. A terpolymer from reaction of vinyl acetate:maleic anhydride copolymer with cyclohexy lamine and 3,3-di-n-butylaminopropylamine (VA:MA-60% cHex-40% DBAPA), gave excellent performance as a KHI, better than the commercially available poly(N-vinyl caprolactam) (PVCap). CO2 corrosion inhibition was measured by Linear Polarization Resistance (LPR) in a 1 litre CO2 bubble test equipment using C1018 steel coupons. The new terpolymer gave good CO2 corrosion inhibition in 3.6 wt% brine, significantly better than PVCap, but not as good as a commercial imidazoline-based surfactant corrosion inhibitor. The terpolymer also showed good corrosion inhibition efficiency at high salinity conditions, (density 1.12 g/cm3). VA:MA-60% cHex-40% DBAPA shifted the open-circuit potential to more positive values and significantly decreased the corrosion rate.publishedVersio