Processes of delta formation in the mouth area of the Ganges and Brahmaputra rivers

The evolution of the Ganges and Brahmaputra river delta during the Holocene period is discussed. Particular attention is given to the processes of delta formation, the dynamics of the delta hydrographic systems, the channel processes in river branches, as well as to the dynamics of the delta coastline and nearshore zone bed over the last 150–200 years. The calculation of sediment budget in the mouth area of these rivers is presented.     

No-z Approximation and rz-Model for Studying Magnetic Fields in Astrophysical Objects

Astronomy Reports - Different astrophysical objects, such as the Sun, another stars, galaxies and accretion discs have regular magnetic field structures. Their generation is usually connected with...     

Applying No-z Approximation in Dynamo for Keplerian Rotation Law

Astronomy Reports - The magnetic fields take place in different astrophysical objects, such as stars, planets, galaxies, accretion discs etc. Their evolution is usually described by the dynamo...     

New Model of the Rupture Surface of the Mw = 7.8 Near Islands Aleutian Earthquake of July 17, 2017 Based on SAR Interferometry

Izvestiya, Physics of the Solid Earth - Abstract—A new model of the rupture surface of the Mw = 7.8 Near Islands Aleutian earthquake that occurred on July 17, 2017 in the region of the...     

A postseismic process in the area of the Simushir 11/2006 Earthquake recovered by the GRACE data

The GRACE data make it possible to detect the areas where the earthquakes initiate postseismic creep in regions much larger than the focal area. This information is important for estimation of the seismic potential and position of the locked segments in the subduction zones.     

Structure and Features of the Galactic Magnetic-Field Reversals Formation

At the present time, the induction of several microgauss in large-scale fields of the Galaxy has been repeatedly confirmed. There are numerous arguments in favor of the fact that the magnetic field exhibits so-called reversals associated with a direction change from one region to another. Such configurations are allowed in the nonlinear equations context of the dynamo theory, which describes the large-scale magnetic-field evolution. In the present study, reversals are modeled using the so-called no-z approximation based on the fact that the galactic disk is sufficiently thin. The magnetic field generation that exhibit both single and double sign changes with distance from the center is observed. From an observational point of view, one of the main methods for studying magnetic fields is to gauge the Faraday rotation measure of radio waves coming from pulsars. Its value can characterize the integral magnitude of the magnetic field, and the sign indicates its direction. A study of the pulsar distribution with large Faraday rotation measures ($$\left| {RM} \right| > 200$$ rad/m2) is presented. The results indicate that there is a region of $$4.8\;{\text{kpc}} < r < 7.3\;{\text{kpc}}$$ in the Galaxy in which the magnetic field is oriented counterclockwise. At the ring edges, the magnetic field reverses its direction. These results are in close agreement both with theoretical concepts and other studies dedicated to the structure observations of the magnetic field in the Galaxy.     

Power spectra of thermal tidal and planetary waves in the near-Earth atmosphere and in the ionospheric D region at Kamchatka

Spectral analysis of the diurnal variations in the quasi-static electric field in the near-Earth atmosphere and VLF atmospheric radio noise at a frequency of 5.3 kHz, simultaneously observed in September–October 1999 at Paratunka observatory of the Institute of Cosmophysical Research and Radiowave Propagation, has been performed. The variations in the intensities of the spectral power density and the period durations of the variations in the T ～ 8–24 h band and higher as functions of geomagnetic and seismic activities have been studied.     

Variations of Trends in Delta Development under the Effect of External Natural and Anthropogenic Factors: Case Study of the Modern Huang He Mouth

The paper considers the major geographic features of the modern Huang He delta, which ranks among the most rapidly varying in the world. The structure of the hydrographic network and the combination of the natural and anthropogenic geosystems of the delta are characterized. The major external riverine and marine, as well as local anthropogenic factors that have affected the development of the Huang He delta in the recent half century are identified. The regularities of the jump-like development of the Huang He delta in the XIX–early XXI centuries are considered. Special attention is paid to the development of the delta after the artificial redistribution of flow in its boundaries in 1996. Satellite images and methods of their interpretation improved by the authors were used. The trends in Huang He delta development are shown to have changed since the last quarter of the XX century under the effect of an abrupt decrease in river sediment load and the growing impact of marine factors. The active progradation of the delta into the sea slowed down significantly, accompanied by erosion and retreat in many segments of its coastline. Huang He delta was used to establish the conditions of changes in the development trends of other deltas under the effect of changes in the climate and economic activity.     

Natural and anthropogenic long-term variations of water runoff and suspended sediment load in the Huanghe river

The hydrographic, climate, hydrological, and landscape features of the Huanghe R. Basin are considered. Water runoff and suspended sediment load in the Huanghe R. are shown to have dropped significantly in 1950–2009 under the effect of regional climate changes and economic activity in the basin. Water balance method and the concept of flow transport competency were used to assess the contribution of natural and anthropogenic factors (decline in precipitation, water withdrawal for economic needs, and the effect of reservoirs) to the decrease in river water runoff and suspended sediment load.