Toward Improving Coastal-Fog Prediction (C-FOG)

Boundary-Layer Meteorology -     

Correction to: Atmospheric Turbulence Measurements at a Coastal Zone with and without Fog

Boundary-Layer Meteorology -     

On the nature of the junction zone between the Vienna and Pannonian sedimentary basins

The results of long-term (2001–2009) measurements of fractures in sedimentary rocks of the Badenian and Pannonian age within the Rust-Fertorakos Highland and adjacent areas are presented and interpreted in terms of paleostresses in the study. The Rust-Fertorakos Highland has a nearly north-south trending strike and separates the Vienna and Pannonian Basins. It is expressed not only in the topography but also in the thickness of the sedimentary cover. Faults in the basement of the Rust-Fertorakos Highland have a nearly north-south strike diagonal to the general NE-SW strike of the faults of the basement of the Vienna Basin. The data of measurements of joints made in quarries and on road slopes that were subsequently computer processed using two independent techniques indicate that, along with joint systems, which are orthogonal to the rock bedding and are of a primary lithogenetic origin, joints joining to form systems obliquely oriented to the bedding are quite common in the region. These secondary joint systems have been formed at later stages of development of already lithified rocks under the influence of tectonic paleostresses. Interpreting pairs of secondary systems as conjugated shear joints, the authors have reconstructed the orientations of the axes of the relevant tectonic paleostresses. At some observation points, the identification of conjugated shear systems has been ambiguous. In these cases, two possible solutions for the paleostress axes have been drawn. Despite some ambiguities, all of the solutions obtained have a steady tendency in terms of the orientation of the minimum compression axis T ₃. This axis is subhorizontal and is oriented nearly east-west with some variation. The maximum compression axis T ₁ and the intermediate principal stress axis T ₂ are normally inclined to the horizontal, and the orientation of these axes depends on the observation point.     

Molecular and isotopic composition of hydrate-bound and dissolved gases in the southern basin of Lake Baikal, based on an improved headspace gas method

Assessments of the molecular and isotopic composition of hydrate-bound and dissolved gases in pore water were conducted during the multi-phase gas hydrate project (MHP-09) cruise VER09-03 to the southern basin of Lake Baikal in September 2009. To avoid changes in gas composition during core sampling and transport, various headspace methods were investigated aimed at preserving the dissolved gases in pore water. When distilled water was added to the sediment samples, the concentrations of carbon dioxide and oxygen decreased because of dissolution into the water and/or microbial consumption. When the headspace was not flushed with inert gases, trace levels of hydrogen and ethylene were detected. The findings suggest that best preparation is achieved by flushing the headspace with helium, and adding a saturated aqueous solution of sodium chloride. This improved headspace method served to examine the molecular and isotopic compositions of gas samples retrieved at several new sites in the southern basin. Methane was the major component, and the proportion of ethane ranged widely from 0.0009 to 1.67?mol% of the total hydrocarbon gases. The proportions of propane and higher hydrocarbons were small or less than their detection limits. The carbon isotope signatures suggest that microbial-sourced methane and ethane were dominant in the Peschanka study area, whereas ethane was of thermogenic origin at all other study sites in the southern basin of Lake Baikal.     

Luminescence in Primordial Helium Lines at the Pre-recombination Epoch

The formation of luminescent subordinate He I lines by the absorption of radiation from a source in lines of the main He I series in an expanding Universe is considered. A burst of radiation in continuum is assumed to occur at some instant of time corresponding to redshift z₀. This radiation is partially absorbed at different z < z₀ in lines of the main He I series (different pumping channels) and then is partially converted into radiation in subordinate lines. If ν _ik is the laboratory transition frequency of some subordinate line emerging at some z, then at the present epoch its frequency will be ν = ν _ik /(1 + z). The quantum yield, i.e., the number of photons emitted in the subordinate line per initial excited atom, has been calculated for different z (and, consequently, for different ν). Several pumping channels have been considered. We show that the luminescent lines can be both emission and absorption ones; the same line can be an emission one for one of the pumping channels and an absorption one for another. For example, the 1s2s–1s2p (1S–1P*) line is an emission one for the 1s2–1s2p pumping and an absorption one for the 1s2–1s3p pumping. We show that in the frequency range 30–80 GHz the total quantum yield for the first and second of the above channels can reach +50 and ?50%, respectively.     

Free convection frequency spectra of atmospheric turbulence over the sea

Frequency spectra of atmospheric turbulenceS (f) in the inertial subrange are considered in the free convection regime over the sea surface in a case of motionless instrument measurements (Eulerian frequency spectra). The frequency spectra formulaef _* S (f)/ ² =c (f _*/f)^5/3 for wind velocity (=1–3), temperature (=t) and humidity (=e) fluctuations are derived on the basis of similarity theory and the –5/3 law. These relations also can be derived from a consideration of convective large-scale advection of small eddies. The frequency scalef _* = (N ^{1 2}/)^1/2 (H/z ²)^1/3 is the lower bound of the inertial subrange and it is of order 10^–2 Hz.The spectra formulae are compared with direct measurements of atmospheric turbulence from the fixed research tower in the coastal zone of the Black Sea in calm weather. It is shown that these formulae are realized at least over two to three decades of the frequency range (approximately from 10^–2 to 10 Hz) and values of the numerical coefficients are found. The derived formulae can be used for calculations of sensible and latent heat fluxes by measuring the high-frequency range of spectra at a fixed point at low wind speeds when the conventional inertial dissipation method is not applicable.     

Local burst model of CMB temperature fluctuations: scattering in primordial hydrogen lines

The propagation of an instantaneous burst of isotropic radiation from the time of its onset at some redshift z ₀ to the time of its detection at the present epoch (at z = 0) is considered within the framework of a flat Universe. Thomson scattering by free electrons and scattering in primordial hydrogen lines (Hα, Hβ, Pα, and Pβ) are believed to be the sources of opacity, with the single-scattering albedo in the lines being calculated by taking into account the deexcitation of the upper levels of the transitions being considered under the action of background blackbody radiation. The profiles of these lines in the burst spectrum at the present epoch have been constructed for various z0 at various distances from the burst center. To a first approximation, these profiles do not depend on the burst radiation spectrum and intensity. It is shown that the lines are purely absorption ones at a sufficiently large distance, but an emission component can appear with decreasing distance, which strengthens as the distance decreases, while the absorption component weakens. The absorption depth in the combined profile can reach 2 ×10^?4 for the Hα and Hβ lines and 7 × 10^?6 for the Pα and Pβ lines. In this case, the relative amplitude of the temperature fluctuations lies within the range 10^?7?10^?9. The calculations have been performed for bursts with different characteristic initial sizes. At the same z ₀, the hydrogen line profiles essentially coincide for sizes smaller than some value, and the contrast of the lines decreases with increasing burst size for greater ones.

     

The formation of polarized lines: Allowance for the Hanle effect

The paper formulates the standard theory for the transport of polarized radiation in the presence of resonance scattering in an atmosphere with a weak magnetic field, so that the Zeeman splitting is small compared to the Doppler line width. For an atmosphere with conservative scattering, this reduces to the Milne problem, which consists of computing a polarized radiation field in a medium with sources lying in infinitely deep layers. In the approximation of complete frequency redistribution, the problem reduces to solving a Wiener-Hopf integral equation for a (6×6)-matrix source function. Asymptotic and numerical solutions for the standard problem are obtained, including solutions for the Milne problem, for the case of a Doppler absorption profile. The line polarization profiles for the emergent flux at various angular distances from the disk center are derived, and the dependence of the limiting degree of polarization (at the line center at the disk edge) on the direction of the magnetic field is computed. For nearly conservative scattering with photon destruction probability ε?1, the limiting degree of polarization varies with ε in accordance with a simple empirical law similar to that found earlier for a medium with zero magnetic field.     

Quantitative Analysis of Samples of Natural Hydrocarbon Reservoirs by the Methods of Integral Geometry and Topology

Izvestiya, Physics of the Solid Earth - Abstract—The paper addresses quantitative analysis of three-dimensional (3D) porous media (natural hydrocarbon reservoirs) based on topological...