Determination of Mesoscale Surface Currents in Shallow-Water Regions According to the Data of High-Frequency Radar Measurements

We propose a new method for the evaluation of the velocities of surface currents according to the data of measurements carried out by using high-frequency land-based radars. The method is based on the representation of the velocity fields via two scalar potentials, expansion of these potentials in series in basis functions, and determination of the coefficients of expansion according to the data of radar measurements as solutions of the corresponding variational problems. The errors of the procedure of determination of the coefficients of expansion are removed by using a special regularization procedure based on information theory. The proposed method enables one to fill gaps in the space and time series of radar measurements. We illustrate the method by an example of numerical analysis of mesoscale and submesoscale (10–50 km) surface currents in the Monterey Bay (California, USA) performed on the basis of the data of radar measurements carried out in August 1994. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 24–36, March–April, 2005.     

Internal Waves in the Shelf Zone and near the Shelf Edge in the Black Sea

The data accumulated by a measuring complex equipped with a gradient-distributed temperature sensor in the course of towing in the shelf zone near the South Coast of the Crimea and in the region where the flow of the Rim Current crosses the shelf edge are used to analyze the energy and space characteristics of internal waves formed when the flow runs through the shelf edge and to study the process of their propagation both to the coast and to the open part of the sea.     

The Influence of Atmospheric Fronts on Free and Forced Oscillations of the Water Level in the Sea of Azov

Doklady Earth Sciences - The influence of inhomogeneous moving atmospheric pressure fields on currents and free and forced oscillations of the level of the Sea of Azov, induced by constant wind, is...     

Finding of Refractory Inclusions in the North Kolchim Meteorite (H3)

Doklady Earth Sciences - For the first time among Russian meteorites, refractory forsterite-rich inclusions are determined in the North Kolchim meteorite (H3). Forsterite-rich inclusions are found...     

Spectrum and Variability of the Supernova Remnant G21.5-0.9

Measurements of the flux densities of the supernova remnant G21.5-0.9 at 4840 and 8450 MHz were performed in 2013–2018 on the 32-m telescope of the Svetloe Observatory of the Institute of Applied Astronomy, Russian Academy of Sciences. Multiple measurements revealed source variability. The flux densities of G21.5-0.9 for 1967–2010 from previously published data are used to compare the intensity of G21.5-0.9 and standard sources. An artificial-Moon flux scale is used to bring all the data into a single system and determine a refined spectrum. Analysis of the resulting data indicates that, first, the observed break in the source spectrum is not associated with energy losses of relativistic electrons due to synchrotron emission and, second, the source variability is manifest as flux-density changes described by one of two power-law dependencies for the flux versus frequency. The spectral indices of each of these dependencies have one of two constant values. Possible origins of the detected changes in the spectrum of G21.5-0.9 are discussed.

     

Solar proton increases and dynamics of the electron outer radiation belt during solar events in December 2006

Increases in solar protons and variations in the electron and proton fluxes from the outer radiation belt are studied based on the GLONASS satellite measurements (the circular orbit at an altitude of ～20000 km with an inclination of ～65°) performed in December 2006. Indications in the channels, registered protons with energies of Ep = 3–70 MeV and electrons with energies of Ee > 0.04 and >0.8 MeV, are analyzed. The data on electrons with Ee = 0.8–1.2 MeV, measured on the Express-A3 geostationary satellite, are also presented. Before the strong magnetic storm of December 14 (|Dst|_max = 146 nT), the maximum of the outer belt electrons with the energy >0.7 MeV was observed at L ～ 4.5. After the storm, the fluxes of these electrons increased by more than an order of magnitude as compared to the prestorm level, and the maximum of a “new” belt shifted to L < 4 (minimal L reached by the GLONASS orbit). Under quiet geomagnetic conditions, solar protons with the energies >3 MeV fill only high-latitude legs of the GLONASS orbit. During the strong magnetic storm of December 15, the boundary of proton penetration into the magnetosphere almost merged with the orbital maximum of the proton radiation belt.     

Formation of the dome-shaped isosurfaces of physical and chemical characteristics of the Black Sea

On the basis of processing and analysis of the results of many-year observations, we study the process of formation of dome-shaped isosurfaces of hydrological and hydrochemical characteristics for all depths in the Black Sea. We estimate the roles of the intensities of sources and sinks of heat and dissolved substances and the general picture of water circulation, vertical exchange, meso- and small-scale anticyclonic vorticity, and mud and geothermal flows to the preservation of the dome-shaped form of the isosurfaces of these characteristics. Translated by Peter V. Malyshev and Dmitry V. Malyshev.     

Distinctive features of circulation of waters in the region of the Zmeiny Island under the action of winds of various directions

We use mathematical simulation to study the response of the sea in the region of the Zmeiny Island to the action of winds of various directions. We describe the processes of reconstruction of circulation and thermohaline structure of waters and, in particular, the location and dimensions of the zones of upwelling and downwelling caused by water surges depending on the direction of the wind. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Ten-antenna prototype of a radio heliograph based on the Siberian Solar Radio Telescope

An upgrade of the Siberian Solar Radio Telescope (SSRT) [Smolkov et al., 1986; Grechnev et al., 2003] to a multiwave radio heliograph has been started. The radio heliograph being created will be designed mainly to measure coronal magnetic fields, to determine the locations of solar-flare energy release, and to investigate coronal mass ejections. These tasks define the parameters of next-generation radio heliographs. A high spatial resolution, a high image acquisition rate, and a high sensitivity are required simultaneously. All these parameters should be realized in the widest possible frequency range—from fractions to tens of GHz). The expected parameters of the future SSRT-based radio heliograph are listed below: spatial resolution 12″–24″, temporal resolution 0.02–1.0 s, frequency range 4–8 GHz, sensitivity up to 100 K, left-hand and right-hand circular polarizations, data rate 0.5–20 Mb s⁻¹ (normal and flare modes). In this paper, we describe the broadband antennas, analog optical data transmission lines, and correlator used in the 10-antenna radio heliograph prototype.