The effect of the pollution of the ground layer of the atmosphere on the albedo

Summary A simple model is proposed suitable for studying the effect of the ground layer of the atmosphere, polluted by aerosol, on the albedo. This model is founded on solving the equation of transfer of radiative energy. The numerical results are discussed, particular attention being paid to the analysis of errors due to neglecting the multiple reflection of solar radiation on the aerosol particles. A method which would also include the multiple reflection is proposed, and the conditions under which the presence of the aerosol is responsible for an increase or decrease of the solar radiation balance on the Earth's surface, are analysed.     

On the solution of the boundary problem of the potential theory by means of the vertical derivative of the gravity anomaly

Summary The boundary problem of the potential theory is treated for the case in which the values of the vertical derivative of the gravity anomaly are known. There boundary conditions are derived and alternatives are also treated.Dedicated to RNDr. Jan Pícha, CSc., on his 60th Birthday     

Comparison Between the Nutations of the Planet Mars and the Nutations of the Earth

The nutations of the planets Mars andEarth are investigated and compared. Alarge number of interior structureparameters are involved in the nutationcomputations. The comparison between the observations and the computationsprovides several constraints on these parmeters andtherefore allows a better understanding of the physics of the interior of theplanet. For the Earth, the high precision of the observations of the nutationshas led to a very good determination of interior properties of the planet. ForMars, observations of nutations are not yet available, and we review how theamplitude of the Martian nutations depends on the hypotheses consideredfor its interior. Although Mars is very similar to the Earth, its interior is not well known;for example, we don't knowif its core is liquid or solid. Only if the core is liquid,the Free Core Nutation (FCN) normal mode exists and can alter the nutationswhich are close to the resonance. From the observed geoids, it is known thatboth planets are not in hydrostatic equilibrium. The departure is larger forMars than for the Earth, and consequently, the implication of considering a convective mantle instead of a mantle in hydrostatic equilibrium described byClairaut's equation for the initial equilibrium state of the planet is largeron the Martian nutations than on the Earth nutations. The consequences of theuncertainty in the core dimensions are also examined and shown to be of a veryhigh influence for Mars if the core is liquid, due to the potential changes inthe FCN resonance. The influence of the presence of an inner core, which isknown to exist for the Earth, could be more important for Mars than for theEarth if the inner core is large. Due to the presence of Tharsis on Mars, thetriaxiality of this planet has, additionally, larger effects than on Earth.     

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.     

上地幔各向异性研究综述及在川滇地区的研究思路

简要介绍了地球介质各向异性研究的发展历程,重点介绍了国内外有关上地幔各向异性的研究工作及成果;阐述了上地幔各向异性的起源及其地球动力学意义;较详细地分析了上地幔各向异性研究的各种方法及其优缺点;论述了川滇地区各向异性研究的意义和目的,并提出了整个研究工作的内容和步骤.     

The effect of the irregularities of the shape of the Earth's core-mantle boundary on the observed acceleration of gravity

Summary The disturbing gravitational effect of the irregularities of the shape of the coremantle boundary are studied at a point on the Earth's surface. The effect is computed for models of local and zonal distribution of the disturbing masses under the assumption that the total mass of the Earth remains constant. Formulae giving the disturbing gravitational effect as a function of the distribution of the disturbing masses and of the position of the point of observation on the Earth's surface are derived for the individual models. Numerical values of the disturbances have been calculate in all cases.     

南极地磁场的变化特性分析

我国南极中山站、长城站地处极区或靠近极光区,地磁场的变化形态与我国所处的中低纬度地区有所不同,即使是中山站与长城站之间也有较大差异。中山站的暴时ＤＰ型变化就比长城站的明显。重构向量空间吸引子的维数也明显高于北京地区。对长城、中山地磁资料的分析可以扩大我们对地磁场全貌的认识。     

Fluctuations of the GPS signals on the tangential paths in the lower terrestrial atmosphere: Influence of the small-scale structure

The small-scale structure of the refractivity distribution due to water vapor density fluctuations in the terrestrial troposphere and lower stratosphere is modeled. Propagation of the signals in the troposphere and lower stratosphere are numerically simulated on the basis of the parabolic equation of diffraction and for occultation geometry. Fluctuations of the signal amplitude on the tangential paths due to small-scale inhomogeneities of the atmospheric refractivity are estimated.     

地磁日变规律的破坏与地震的关系研究

2001年11月14日昆仑山8.1级地震前，震中距为400km的格尔木台地磁垂直分量Z的日变形态发生异常，1998年1月10日张北Ms6.2地震前，北京台和静海台Z的日变形态也有异常。但是，2000年1月15日云南姚安Ms6.5地震和1月27日丘北Ms5.5地震前，通海台的Z分量无异常。这可能与地震的复杂性有关。     

山西榆次地裂缝的分布及活动特征

在实地调查、填图的基础上 ,揭示了山西榆次地裂缝的分布特征及活动特征 ,得出地裂缝呈南北向和北东向带状分布 ,大都表现为建筑物的破裂 ,局部地段为地表裂缝和塌陷 ,呈水平张裂 ,地表破裂无垂直差异和扭动运动痕迹的结论     

Vertical movements of the Earth's crust on the continents

Vertical oscillating movements of the Earth's crust on continents have occurred and are occurring everywhere on the Earth's surface, continuously throughout the entire geological history of the Earth. This provides grounds to consider them as the basic type of tectonic movements, which form the general background of the tectogenetic process, on which locally, and only at separate moments of time, other tectonic movements and deformations appear.According to the time of occurrence, the vertical movements are divided into recent, young, modern, and ancient. In compliance with this subdivision, different methods are applied to define and study the movements. The major characteristic of the vertical movements is their rhythm, or periodic change in sign of movement, which caused them to be calledoscillating. Rhythms of movements are of several orders. The largest rhythms, which comprise tectonic cycles, are manifested on a global scale; smaller rhythms have a local distribution. It is significant that, in the beginning and in the end of each tectonic cycle, an increase of intensity and contrast of movements is observed, no matter in which region or regime, whether stable or mobile, it occurs.     

Geoelectric structure of the lithosphere of the Northern Urals

A geoelectric structure of the lithosphere is constructed to a depth of 300 km on the basis of experimental electromagnetic studies along the geotraverse crossing all of the major first-order structural zones in the Northern Urals. Important constraints on the crust and upper mantle layering are obtained from electric parameters at various depth levels. Together with the compositions of rocks, including the crust of weathering, structural-tectonic relations between geological objects (complexes and faults) identified at the Earth’s surface and characteristics of the deep geoelectric structure are established in upper parts of the section.     

Influence of the topography of the surface of the Earth on vertical sounding of the temperature profile

Atmospheric temperature and humidity fields as well as information on other meteorological parameters are nowadays retrieved from radiance measurements recorded by operational meteorological satellites. Up to now, the inversion procedures used only take into account crude information on the topography of the Earth’s surface. However, the applied radiative transfer codes have to consider the Earth’s surface as the lower boundary of the atmospheric model and, therefore, need a more precise mean elevation and a classification of the roughness of the Earth’s surface. The influence of the topography of the Earth surface on retrieved temperature profiles is studied by using a physico-statistical inversion method. An objective analysis is made of the more precise mean elevation and derivation of roughness parameters using a new high-resolution digital elevation model (DEM) with a resolution of 500 m×500 m. By means of a geomorphological process and a newly developed topography rejection test, areas with a high surface roughness are localized and singled out. The influence of topography on the retrieved temperature profiles is illustrated by case studies. Changes are found predominantly in areas with a high variation of topography. Using the new high-resolution DEM and the topography rejection test, the geographical position of the calculated temperature profiles tends to be shifted towards areas with a small vertical variation of topography. The mean elevation determined by the new elevation model better characterizes the area observed. Hence, the temperature profiles can be calculated down to lower atmospheric levels. Furthermore, a guess profile better describing the atmospheric situation is selected by the more precise elevation. In addition, the temperature profiles obtained near the coast are improved considerably by the more precise determination of the surface property ‘sea’ and ‘land,’ respectively. Integration of an independent physical information such as topography leads, on average, to a slight improvement of the results of the physico-statistical inversion procedure. In some cases, however, significant improvements have been achieved regarding the desired accuracy of temperature profiles of the order of 1 K. In future, the spatial resolution of new high-resolution sounding instrumentation on the next generation of operational meteorological satellites will be increased. To exploit the resolving power of this new instrumentation, the different variation of the topography of the Earth surface, especially in regions with a high variation of topography, can be taken into account more precisely by using a high-resolution DEM.     

Tilts due to the free nutation of the Earth's axis in the results of geodetic observations

Summary Simple expressions for the deformation of equipotential surfaces and changes of the deflections of the vertical are derived at points of the Earth's surface, which are due to the variations of the rotational component of the gravity potential under free nutation of the Earth's axis of rotation (pole wandering). The results of the solution of this problem given in[1] are discussed. The values of the tilts and the changes of geoid heights for extreme deviations of the poles are considered from the point of view of the effect on measuring tilts and on levelling. An elastically deformable Earth is assumed. It is concluded that reductions with respect to the mean Earth's pole are not realistic at the present degree of accuracy of levelling. The necessity to reduce long-term tilt observations, or the possibility of determining the time variations of the rotational axis from the analysis of these observations is pointed out.     

Impact of the blockage ratio on the transport of sediment in the presence of a hydrokinetic turbine: Numerical modeling of the interaction sediment and turbine

Interactions between hydrokinetic turbines and near scale and far scale bed sediment particles are considered a critical area of assessment; however, a limited number of research studies have been published to address this issue. The current paper explores the influence of the blockage ratio on the morphology evolution downstream from a hydrokinetic turbine. A modeling framework is derived to predict the significant transport induced by a turbine installed on the erodible fluvial sandy bed surface, such as the Eulerian multi-phase model for the sediment and the Blade Element Momentum Theory (BEMT) for the turbine, using the open source platform OpenFOAM. Two configurations of different blockage ratios are considered. The configurations show differences in the bed morphology and the sediment transport. It has been shown for both configurations that the scour capabilities are enhanced below the turbine due to the acceleration of the flow and increasing local shear stress on the sediment.     

Estimates of the energy of surface waves from atmospheric explosions and the source parameters of the Tunguska event

The results of the numerical modeling of experimental concentrated atmospheric explosions, both nuclear and chemical, are presented. The surface pressure spectra are calculated and constraints are gained on their relation to the energy of surface seismic waves and to earthquake magnitudes. For a more accurate determination of the source parameters of the Tunguska event (June 30, 1908), atmospheric explosions at various altitudes and vertical falls of meteoroids are modeled numerically and their seismic effect is estimated.     

Dynamics of the marine coastal zone of the sea near the entrance moles of the Kaliningrad Seaway Channel

The results of multidisciplinary field studies of a segment of the coastal zone (in the area near the Baltiysk Strait South-East Baltic) are presented. The natural regime of the evolution of this zone has changed under the effect of anthropogenic factor. Bed topography, bottom sediments, and shore morphology and dynamics are characterized. The effect of entrance moles has resulted in the formation of various local hydrolithodynamic conditions on both sides of these moles, including the accumulation of sedimentary material and the seaward protrusion of the coastline in the north and the permanent erosion of the shore in the south. To reduce the adverse effect of hydrodynamic processes on the coastal zone south of the moles it is proposed to use the clean material extracted during strait dredging.     

大陆岩石圈流变结构研究进展及存在问题

自20世纪60年代以来,大陆岩石圈流变学取得了较大的进展,理论和应用研究不断深入.理论上,人们不仅认识到在构造运动中岩石圈介质是流变体而非简单的刚体性和弹性体;并利用矿物和岩石的实验结果提出了岩石圈流变分层的概念,建立了一维流变模型;进而用流变的观点解释了一些具体构造现象,而且开始了三维流变结构的研究,提出了岩石圈流变结构的横向分块纵向分层的观点.应用上,人们已从把流变强度曲线简单地运用于运动学或动力学模型的阶段,进入了在三维空间中定量研究地球动力学问题的阶段.随着岩石圈流变学研究的深入及大陆岩石圈的复杂性,新的问题也不断涌现.     

Hydrological–Morphological Zoning of the Mouth Zone of the Selenga River

According to the two-term principle of zoning of mouth areas, parts of the mouth area of the Selenga River are recognized and their boundaries are determined based on hydrological–morphological characteristics.