Distribution of some ions and minor gaseous components by concentrations in the atmospheric surface layer of some regions in Eastern Siberia and the Far East

We consider the resemblance between the ion composition of the fraction of soluble aerosols and gaseous admixtures in the atmospheric surface layer at the high-level Mondy station (East Sayan), those in the Listvyanka settlement south of Lake Baikal, in the city of Irkutsk, and at the Primorskaya station near the city of Ussuriysk (Primorskii krai). We use measurement data on the concentrations of the following ions: HCO ₃ ^? , SO ₄ ^2? , NO ₃ ^? , Cl^?, H⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺ in the soluble fraction of aerosols and gases HNO₃, HCl, NH₃, and SO₂ in air samples over a 10-year period conducted in the mode of online monitoring. We found the lognormal form of distributions of concentrations of each of the abovementioned components according to the number of samples. A versatile scheme of the distribution of mean geometric concentrations of atmospheric components was proposed for all four groups.     

Filter-based differential hygroscopicity analyzer of aerosol particles

We describe a new differential analyzer implementing a technique for studying the hygroscopic properties of filter-precipitated aerosol particles based on a katharometric measurement of the amount of water vapor absorbed by an aerosol sample. The instrument has been tested on particles of sodium chloride and ammonium sulphate. A comparison of our data with the results of analogous measurements described in literature shows that the suggested technique has several important advantages, i.e., (1) higher sensitivity, which allows the measurement of particles of no more than 0.1 mg in mass; (2) a wide range of relative humidity variations (up to 99% at an accuracy of 0.06% RH at the upper-range value); (3) the absence of intermediate measurement steps connected with the need to account for water absorption by elements of a measurement system; and (4) the absence of restrictions to the size and shape of particles studied. In addition, the measurement technique rules out the possibility of errors caused by the kinetic effects of mass transport in the aerosol-water vapor system.     

The GEM project: An international collaboration to survey galactic radiation emission

The GEM (Galactic Emission Mapping) project is an international collaboration established with the aim of surveying the full sky at long wavelengths with a multi-frequency radio telescope. A total of 745 hours of observation at 408 MHz were completed from an Equatorial site in Colombia. The observations cover the celestial band 0 ^h <<24 ^h , and –24° 22<<+35° 37. Preliminary results of this partial survey will be discussed. A review of the instrumental setup and a 10° resolution sky map at 408 MHz is presented.Presented by S. Torres at the UN/ESA Workshop on Basic Space Sciences: From Small Telescopes to Space Missions, Colombo, Sri Lanka 11–14 January 1996     

Petrology and oxygen isotopic compositions of clasts in HED polymict breccia NWA 5232

Northwest Africa (NWA) 5232, an 18.5 kg polymict eucrite, comprises eucritic and exogenic CM carbonaceous chondrite clasts within a clastic matrix. Basaltic clasts are the most abundant eucritic clast type and show a range of textures and grain size, from subophitic to granoblastic. Other eucritic clast types present include cumulate (high‐En pyroxene), pyroxene‐lath, olivine rich with symplectite intergrowths as a break‐down product of a quickly cooled Fe‐rich metastable pyroxferroite, and breccia (fragments of a previously consolidated breccia) clasts. A variable cooling rate and degree of thermal metamorphism, followed by a complex brecciation history, can be inferred for the clasts based on clast rounding, crystallization (and recrystallization) textures, pyroxene major and minor element compositions, and pyroxene exsolution. The range in δ¹⁸O of clasts and matrix of NWA 5232 reflects its origin as a breccia of mixed clasts dominated by eucritic lithologies. The oxygen isotopic compositions of the carbonaceous chondrite clasts identify them as belonging to CM group and indicate that these clasts experienced a low degree of aqueous alteration while part of their parent body. The complex evolutionary history of NWA 5232 implies that large‐scale impact excavation and mixing was an active process on the surface of the HED parent body, likely 4 Vesta.     

Seasonal Dynamics of Microbial Processes in Bottom Sediments of the Sevastopol Coastal Area

Oceanology - A seasonal study of microbial methane oxidation (MO) and sulfate reduction (SR) processes in bottom sediments was carried out at five stations in the estuarian Sevastopol coastal area,...     

Experimental Studies of Aerosols in the Atmosphere of Semiarid Landscapes of Kalmykia: 1. Microphysical Parameters and Mass Concentration of Aerosol Particles

Izvestiya, Atmospheric and Oceanic Physics - This paper summarizes the results of long-term (2004–2016) comprehensive experimental studies of microphysical parameters and the mass...     

High-resolution numerical modelling of convective precipitation over Northern Italy

Summary A number of forecast experiments were performed in order to assess the capability of reproducing, by means of a limited-area numerical model, the highly structured mesoscale circulations occurring in the Po Valley of Northern Italy during a north-westerly cold front passage across the Alpine chain, with particular attention to the modelling of the effects of organized convection. The case-study occurred during summer 1987 and the model used throughout was the 1989 version of the UB/NMC Limited Area Model (University of Belgrade, National Meteorological Centre of Washington). The model was integrated both with eta, , and sigma, , as vertical coordinates and ECMWF initialized analyses were always used as initial conditions. ECMWF initialized analysis or operational forecast fields were also used for updating in time the lateral boundary conditions. Experiments show qualitative and quantitative agreement with observations, both in upper-air geopotential height fields, in MSLP and in cumulated precipitation. Several modelling issues were also investigated, e.g. sensitivity of the results to horizontal and vertical model resolution and to the influence of the lateral boundaries poitioning, finding large effects of the latter on quantitative precipitation fields. Difficulties in modelling very localized mesoscale phenomena, e.g. organized convective thunderstorms in the Po Valley and Alpine North Foehn in the Milan area, were generally encounted.     

NEW 10BE COSMOGENIC AGES FROM THE VIMMERBY MORAINE CONFIRM THE TIMING OF SCANDINAVIAN ICE SHEET DEGLACIATION IN SOUTHERN SWEDEN

The overall pattern of deglaciation of the southern part of the Scandinavian Ice Sheet has been considered established, although details of the chronology and ice sheet dynamics are less well known. Even less is known for the south Swedish Upland because the area was deglaciated mostly by stagnation. Within this area lies the conspicuous Vimmerby moraine, for which we have used the terrestrial cosmogenic nuclide (¹⁰Be) exposure dating technique to derive the exposure age of six glacially transported boulders. The six ¹⁰Be cosmogenic ages are internally consistent, ranging from 14.9 ± 1.5 to 12.4 ± 1.3 ka with a mean of 13.6 ±0.9 ka. Adjusting for the effects of surface erosion, snow burial and glacio-isostatic rebound causes the mean age to increase only by c. 6% to c. 14.4± 0.9 ka. The ¹⁰Be derived age for the Vimmerby moraine is in agreement with previous estimates forthe timing of deglaciation based on radiocarbon dating and varve chronology. This result shows promise for further terrestrial cosmogenic nuclide exposure studies in southern Sweden.     

Sources of Zircons from Cretaceous and Lower Paleogene Terrigenous Sequences of the Southern Koryak Upland and Western Kamchatka

The mineral composition of sandstones from Cretaceous–Lower Paleocene terrigenous sequences of the western Kamchatka–Ukelayat zone (southern Koryak Upland, western Kamchatka) suggests that the Okhotsk–Chukot volcanogenic belt and fragments of the Uda–Murgal island arc served as the most probable provenance. Fission-track dating of zircon showed that sandstones from this zone contain detrital zircon of several different-age populations. Fission tracks in zircon grains were nor subjected to secondary ignition. The age of young zircon population coincides with the biostratigraphic age of host sequences. Thus, results of dating of detrital zircon grains from sandstones, which did not experience heating above 215–240°C, indicate that this method is appropriate for dating fossil-free terrigenous sequences. The young zircon population in the sandstones is related to erosion of plagiogranite and diorite intrusions of the Uda–Murgal arc and outer zone of the Okhotsk–Chukot volcanic belt exposed at the day surface owing to differential vertical movements and rapid exhumation of blocks.     

Accuracy estimates for some global analytical models of the Earth’s main magnetic field on the basis of data on gradient magnetic surveys at stratospheric balloons

Two global analytical models of the main magnetic field of the Earth (MFE) have been used to determine their potential in deriving an anomalous MFE from balloon magnetic surveys conducted at altitudes of ～30 km. The daily mean spherical harmonic model (DMSHM) constructed from satellite data on the day of balloon magnetic surveys was analyzed. This model for the day of magnetic surveys was shown to be almost free of errors associated with secular variations and can be recommended for deriving an anomalous MFE. The error of the enhanced magnetic model (EMM) was estimated depending on the number of harmonics used in the model. The model limited by the first 13 harmonics was shown to be able to lead to errors in the main MFE of around 15 nT. The EMM developed to n = m = 720 and constructed on the basis of satellite and ground-based magnetic data fails to adequately simulate the anomalous MFE at altitudes of 30 km. To construct a representative model developed to m = n = 720, ground-based magnetic data should be replaced by data of balloon magnetic surveys for altitudes of ～30 km. The results of investigations were confirmed by a balloon experiment conducted by Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation of the Russian Academy of Sciences and the Moscow Aviation Institute.