On the connection between the atmospheric electric field measured at the surface and the ionospheric electric field in the Central Antarctica

Regular measurements of the atmospheric electric field made at Vostok Station (φ=78.45°S; λ=106.87°E, elevation 3500 m) in Antarctica demonstrate that extremely intense electric fields (1000–5000 V/m) can be observed during snow storms. Usually the measured value of the atmospheric electric field at Vostok is about 100–250 V/m during periods with “fair weather” conditions. Actual relation between near-surface electric fields and ionospheric electric fields remain to be a controversial problem. Some people claimed that these intense electric fields produced by snowstorms or appearing before strong earthquakes can re-distribute electric potential in the ionosphere at the heights up to 300 km. We investigated interrelation between the atmospheric and ionospheric electric fields by both experimental and theoretical methods. Our conclusion is that increased near-surface atmospheric electric fields do not contribute notably to distribution of ionospheric electric potential.     

Distances to dwarf galaxies of the Canes Venatici I cloud

We determined the spatial structure of the scattered concentration of galaxies in the Canes Venatici constellation. We redefined the distances for 30 galaxies of this region using the deep images from the Hubble Space Telescope archive with the WFPC2 and ACS cameras.We carried out a high-precision stellar photometry of the resolved stars in these galaxies, and determined the photometric distances by the tip of the red giant branch (TRGB) using an advanced technique and modern calibrations. High accuracy of the results allows us to distinguish the zone of chaotic motions around the center of the system. A group of galaxies around M94 is characterized by the median velocity V _LG = 287 km/s, distance D = 4.28 Mpc, internal velocity dispersion σ = 51 km/s and total luminosity L _B = 1.61 × 10¹⁰ L _?. The projection mass of the system amounts to M _p = 2.56 × 10¹² M _?, which corresponds to the mass-luminosity ratio of (M/L) _p = 159 (M/L)_?. The estimate of the mass-luminosity ratio is significantly higher than the typical ratio M/L _B ～ 30 for the nearby groups of galaxies. The CVn I cloud of galaxies contains 4–5 times less luminous matter compared with the well-known nearby groups, like the Local Group, M81 and CentaurusA. The central galaxy M94 is at least 1^m fainter than any other central galaxy of these groups. However, the concentration of galaxies in the Canes Venatici may have a comparable total mass.     

Longitude and latitude structure of the polar activity of the Sun in the 21st cycle

A catalog of observations of polar faculae by the Mountain Astronomical Station of the Pulkovo Observatory (Kislovodsk) for the 21st polar-activity cycle of the Sun (1972–1976) has been compiled. The mean annual and semiannual longitude distributions of the facular surface density have been constructed for latitude bands from 35 to 85° with steps of 10° in latitude and 30° in longitude in polar (the “wind roses”) and cylindrical projections, using a Bartels coordinate-grid rotation system. Coherent spatial structures in these distributions, which are characteristically elongated in two mutually perpendicular directions (i.e., they have an “X”-like appearance), can be identified. The high-latitude activity in the northern and southern hemispheres tends to be in spatial antiphase. This behavior corresponds to a four-sector global polar-activity structure. This indicates the presence of a magnetic-field source that is not associated with the differential rotation of the sun and modulates the evolution of local magnetic fields.     

Holocene overbank deposition in the drainage basin of Lake Khanka

Overbank deposits in the Komissarovka River valley consist of alternating silt, clay silt, sand, and soils produced by lacustrine, alluvial, and aeolian deposition and by soil formation. Silt and sand layers in the lower part of the section correlate with the events of Early Holocene transgression and Middle Holocene regression of Lake Khanka. Deposition in the lowermost reaches of the Komissarovka River provides a faithful record of local Holocene landscapes controlled by level changes in Lake Khanka.     

Study of the factors determining anomalous variability of carbon dioxide total column amount over St. Petersburg

Results of spectroscopic measurements of the carbon dioxide total column amount near St. Petersburg during forest fires in the period from August to September 2002 are analyzed. The HYSPLIT model is used to calculate air-mass trajectories and CO distribution on a mesoscale in this period. The HYSPLIT model simulations and measurements of carbon dioxide total column amount yield an estimate of the specific intensity of CO emission in a Pskov forest fire on August 28–September 8, 2002, equal to 0.17–0.26 kg m². This estimate can be used for an estimation of the integral CO emission from fires in northwestern Russian forests and for model simulations of atmospheric CO concentration fields. The estimate of the CO emission from forest fires that is obtained from ground-based measurements can also be made on the basis of satellite measurements if they contain information on CO in the lower tropospheric layers (0 to 2 km).     

Series of classical solar activity indices: Kislovodsk data

We present data on the series of solar activity indices, Wolf sunspot numbers W and total sunspot areas S, obtained at the Kislovodsk high-altitude station of the Pulkovo Observatory. The problem of properly extending the 133-year-long Zürich series of W and the 102-year-long Greenwich series of S, which were discontinued in 1980 and 1976, respectively, is emphasized. We stress that the Kislovodsk data have retained mutual homogeneity with the classical series until now and that they are preferred for extension. The question under consideration is of fundamental importance in studying the solar activity variations on long time scales and related processes in the Sun-Earth system.     

“Hot” particles of the Yenisei River: Radioisotope composition,structure, and behavior in natural conditions

The radioisotope compositions, structure, and behavior of “hot” particles under the natural conditions of the Yenisei River in the nearby influence zone of Krasnoyarsk mining and chemical combine were examined in this study. By the composition of gamma-radiating isotopes, all particles are divided into three groups: mono-isotopic, bi-isotopic and poly-isotopic. Mono-isotopic “hot” particles, containing only ⁶⁰Co were discovered for the first time. Transuranium elements (²⁴¹Am and ²⁴³Cm) were revealed in poly-isotopic particles. Investigation of poly-isotopic particles by means of a scan electron microscope showed that the presence of UO₂ together with the lack of activation of ¹⁵²Eu testifies to the reactor origin of this particle. Experiments showed that in natural conditions “hot” particles under the influence of filtrating water and moisture of pore solutions are gradually dissolved and radionuclides are repeatedly drawn into migration.     

On the variability of some characteristics of solar radiative flux

We present estimates of the variability of the total solar flux and its spectral components of different wavelength intervals in the region from 1 nm to 240 mm with a time-scale to 11-years. We used the data published in the monograph Solar radiation flux (by E.A.Makarova et al., 1991) as well as new available data.     

A colour-agnitude diagram of the Pisces dwarf galaxy

We present B, V and R band CCD images of the dwarf galaxy LGS-3 (Pisces dwarf). About 180 stars and diffuse objects were found and processed in these frames. The colour-magnitude diagram shows a prominent red giant branch and a few blue stars only. Details of the morphological properties and colour-agnitude diagram indicate to an intermediate (between dIrr and dSph) type of LGS-3. We estimate the galaxy distance modulus to be about (m - M)₀ = 23.9 ± 0.3 mag on the basis of the tip of the red giant branch. We measured the galaxy colour to be about B–V = 0.8 mag and the linear diameter 700 pc, which is the smallest one in the Local group.     

Spatial–Temporal CO2 Variations near St. Petersburg Based on Satellite and Ground-Based Measurements

Izvestiya, Atmospheric and Oceanic Physics - The results of studying spatial–temporal CO2 variations near St. Petersburg in 2014–2017 based on satellite measurements (OCO-2 satellite)...