Pollution of Russian Northern Seas with Heavy Metals: Comparison of Atmospheric Flux and River Flow

Izvestiya, Atmospheric and Oceanic Physics - Fluxes of anthropogenic heavy metals (Pb, Cd, As, Zn, Ni, Cr, and Cu) to the surface of four seas (White, Pechora, Kara, and Laptev seas) in the Russian...     

The orbit of asteroid (99942) Apophis as determined from optical and radar observations

The results of improving the orbit accuracy for the asteroid Apophis and the circumstances of its approach to Earth in 2029 are described. Gravitational perturbations from all of the major planets and Pluto, Ceres, Pallas, and Vesta are taken into account in the equations of motion of the asteroid. Relativistic perturbations from the Sun and perturbations due to the oblateness of the Sun and Earth and due to the light pressure are also included in the model. Perturbations from the Earth and Moon are considered separately. The coordinates of the perturbing bodies are calculated using DE405. The phase correction and the gravitational deflection of light are taken into account. The numerical integration of the equations of motion and equations in variations is performed by the 15th-order Everhart method. The error of the numerical integration over the 2005–2029 interval, estimated using forward and backward computations, is not more than 3 × 10^?11 AU. Improved coordinates and velocities at epoch JD2454200.5 (April 10, 2007) were obtained applying the weighted leastsquares fit. For the period from March 15, 2004, to August 16, 2006, 989 optical and 7 radar observations were used. The resulting system represents the optical observations with an error of 0.37 (66 conditional equations were rejected). The residuals of the radar observations are an order, or more, smaller than their errors. The system of Apophis’ elements and the estimates of their precision obtained in this study are in perfect agreement with the results published by other authors. The minimum Apophis-Earth distance is about 38 200 km on April 13, 2029. This estimate agrees to within 20 km with those calculated based on other published systems of elements. The effect of some model components on the minimum distance is estimated.     

Variability of Surface Methane Concentration in Moscow at Different Time Scales

Izvestiya, Atmospheric and Oceanic Physics - The variability of surface methane (СН4) concentration in Moscow at different time scales is analyzed using long-term regular measurements...     

Buzulgan Rockslide: Simulation of Debris Flows along Gerkhozhan-Su River and Scenarios of Their Impact on Tyrnyauz Town after Changes in 2020

Water Resources - Three likely scenarios of debris flow development in the valley of the Gerkhozhan-Su river are discussed: (I) the passage of a debris flow comparable with that in 2017; (II) a...     

Environmental Effects of the Bottom Sediments of the Senezh Reservoir

The formation and accumulation of bottom sediments in the Senezh Reservoir are discussed on the basis of field observations. Data on the bottom sediment thickness, the rates of accumulation, and the concentrations of organic substances, metals, petroleum products, and organic pollutants are presented. The bottom sediments of the reservoir are demonstrated to be still no source of secondary pollution.     

The experimental debris flows in the Chemolgan river basin

Debris flows are one of the most dangerous and common hydrological phenomena in mountainous regions. They are extremely various in their type and character, but they are always mountain flows consisting of a mixture of water and loose-fragmental debris. The problem of calculation and forecasting the mudflows still remains intractable. There are several reasons for that: Firstly, the representatives of the whole spectrum of the Earth Sciences (Hydrology, Geology, Geomorphology, Geography, Mechanics, Rheology) deal with this problem from their point of view. Secondly, systematic monitoring of passing debris flows are currently held only in several countries only (USA, Canada, Austria, Switzerland, Japan, China), because they require significant funding. Thirdly, the calculation methods, having been accepted for the present time, give certain errors. In this article, the results of the artificially triggered debris flow experiments conducted in 1972–1976 in the Chemolgan river basin, organized by the Kazakh Research Hydrometeorological Institute are described. These were the first full-scale experiments with the detailed recording of the numerous debris flows characteristics ever conducted. The movie is attached as supplementary material to the Editorial of the Special Issue. The information about the used measurement equipment, the obtained characteristics of debris flows, the debris flow classification accepted as a result of the experiments is given. Conducting such experiments in nature allowed us to assess various aspects of the formation of these natural phenomena and made it possible to build the mathematical models of the debris flow processes.     

Properties of the distribution of azimuthal magnetic field in a plasma flow during laboratory simulations of astrophysical jets in a plasma-focus installation

The results of laboratory simulations of astrophysical jets are presented. Plasma flows generated in the PF-3 plasma-focus installation of the NRC “Kurchatov Institute” and propagating to distances substantially exceeding their transverse dimensions are studied. It is shown usingmagnetic probes that the plasma flow propagates with a frozen-in magnetic field. The resulting radial distribution of the azimuthal magnetic field corresponds well to the distribution created by a longitudinal current of ~10 kA flowing in a region with a radius of 1–2 cm near the axis. Structures associated with return currents are observed at the periphery of the flow. The magnetic field decays rapidly as the flow propagates along the axis. Nevertheless, the leading lobe of the plasma flow is preserved to substantial distances in a neon discharge, possibly due to radiative cooling of the plasma.     

Calculation of Tidal Displacements and Tilts for a Nonelastic Rotating Earth

Izvestiya, Atmospheric and Oceanic Physics - A technique for calculating tidal displacements and tilts for the Earth both with the ocean and without it is presented in this work. This technique...     

Oceanic Tide Model FES2014b: Comparison with Gravity Measurements

Izvestiya, Atmospheric and Oceanic Physics - The oceanic gravimetric effect is calculated by expanding the cotidal maps of the FES2014 oceanic tide model into spherical functions with the use of...