Geomagnetic Pc3 Pulsations During the Total Solar Eclipse on Aug 11, 1999

The solar eclipse on August 11, 1999, observed in the region covered by many geomagnetic observatories, has offered a unique opportunity to look for an effect of the eclipse on geomagnetic pulsations. The pulsation activity digital data have been taken from Budkov Observatory in the Czech Republic (in the X component only), from observatories in Germany (Niemegk, Fürstenfeldbruck, Bad Bergzabern), in Hungary (Nagycenk), and for comparison in South Africa (Hermanus, conjugate-point station), and in Finland (Sodankylä, far from the eclipse zone). At all these stations the field in all three component has been recorded. The pulsation amplitudes in the X component exhibit a long-term minimum near the time of the eclipse. Spectral analysis of selected short intervals confirmed this decrease and also revealed a decrease of the average pulsation period during the eclipse. Such a change in the amplitude or in the period was not observed outside of the eclipse interval or in other days. Investigation in some narrower frequency bands showed that the maximal decrease occurred in the 15–20 s band. All these changes can be found in records from all the stations near the eclipse totality belt, also in records at the conjugate-point station, where no eclipse occurred. No signature has been found in records at the station situated far from the eclipse zone.     

Contribution of Major Groups of Autotrophic Organisms to Primary Production of Water Bodies

Regularities in the development of macrophytes, epiphytes, and phytobenthos, common for different types of water bodies, are first described. The dependence of their production on the morphometry of lakes, total phosphorus content, water transparency, and latitude is examined. The total phosphorus content is shown to affect primarily the development of phytoplankton and to have only indirect effect on the development of macrophytes, epiphytes, and phytobenthos. A mass-balance model for prediction of the biomass and annual production of phytoplankton, macrophytes, epiphytes, and phytobenthos is suggested.     

日本古代的一次可能的日全食与地球自转变化

利用古代日食观测记载研究地球自转长期变化的方法和已有的结果为基础，研究了日本的古书中记载的可能与古代一次日全食有关的“天门”传说，及朝鲜的古书中与此有关的记载。本文的结果支持一些学者认为这个传说是由发生于公元158年7月13日的日全食引起的观点，并在历书时ET系统下计算分析了该日食的参数，由此得到表示地球自转变化的△T值约为2．22小时。     

Joint observation results of Na layer and ionosphere in Wuhan during the Total Solar Eclipse

During the total solar eclipse on July 22, 2009 in Wuhan, the joint observation test of Na layer and ionosphere was conducted by using the daytime observation atmospheric lidar and the GPS ionosphere detector. The results show that the full width at half maximum (FWHM) of Na layer density slightly narrowed during the total solar eclipse and broadened after the eclipse, while the height of Na peak slightly decreased in the eclipse and increased after the eclipse. These implying that Na layer changes reflect the rapid process of sunrise and sunset. The ionosphere total electron content (TEC) and the sky background light noise also presented an obvious fluctuation characteristic with the changes of solar irradiation during the process of total solar eclipse. The difference lies in that the changes of FWHM of Na layer atoms are much slower than that of ionosphere, the reason for this might be that the Na layer, after being disturbed by the total solar eclipse, will generate a series of complicated photochemical reactions and momentum transport processes, and then recombine the Na atoms. The Na atoms to be detected by the lidar need a lag process, which rightly conforms to the theoretical simulated results.     

Water Resources of Natural and Artificial Water Bodies in Europe

Water Resources - The reserves of natural and artificial water bodies in Europe were evaluated using a new procedure which had been developed for Russian territory and upgraded for the territories...     

Geomagnetic Field Variations during the Total Solar Eclipse of 2 July 2019 in La Serena,Chile

Geomagnetism and Aeronomy - The total solar eclipse on July 2, 2019, has been studied by using data of the La Serena ground magnetic station in Chile located in the path of the totality (at...     

Features of the Ionospheric Total Electronic Content Response to the Annular Solar Eclipse of June 21, 2020

Geomagnetism and Aeronomy - The features of the annular solar eclipse of June 21, 2020, in variations of the ionospheric total electron content (TEC) were analyzed using GPS observations of the IGS...     

The Density of Bottom Sediment Particles in Water Bodies

Water Resources - The density of particles in the bottom deposits of water bodies is an important characteristic, which determines the rate of interaction between bottom water layers with the...     

Changes in Hydrochemical Characteristics of Water Bodies in the Southern Aral Region

Based on the hydrochemical characteristics of water bodies in the northwestern part of the southern Aral Sea region, limnic ecosystems are shown to be liable to anthropogenic changes. The dynamics of the salinity, ionic composition, oxygen content of water, and nutrients under human impact on water bodies of the southern Aral Sea region are shown.     

Numerical Modeling of Wind-Induced Flows in Stratified Water Bodies

Two-dimensional (in the vertical plane) wind-induced flows in no-flow-through reservoirs are considered. A numerical algorithm in the flow function–vortex variables is proposed based on the equations of slow stratified flows in the Boussinesq and boundary layer approximations with variable coefficient of vertical turbulent exchange. An analytical solution is given for a simplified problem.     

The Role of Filtering Zooplankton in De-Eutrophication of Water Bodies

The filtration capacity of large-size cladoceras is examined. Cladoceras Simocephalus vetulus with a biomass of 1.6 g/l in flow-through ecosystems isolated from ichthyifauna can reduce phytoplankton biomass from 2.89 to 0.12 mg/l within 1 h. Particularly, the biomass of blue-green algae Anabaena spiroides decreases from 0.14 to 0.01 mg/l, and their filaments shorten. In the period when phytoplankton biomass in the water body was at maximum, the activity of cladoceras (biomass of 2.1 g/l) resulted in a decrease in this biomass in flow-through ecosystems by a factor of 13.6 (down to 0.34 mg/l). The decrease in phytoplankton biomass in flow-through ecosystems facilitated changes in its composition in the water body (an increase in the share of green algae) and was accompanied by an increase in water transparency.__________Translated from Vodnye Resursy, Vol. 32, No. 3, 2005, pp. 371–379.Original Russian Text Copyright © 2005 by Pogozhev, Gerasimova.     

Current Problems in Organizing Water Protection Zones at Water Bodies: Case Study of the Uglich Reservoir

A retrospective review of the current scientific publications on the problems of water protection zones at water bodies is given. The content of regulations on water protection zone in the RF Water Code 2006 now in force is interpreted. The legislations regarding the establishment of water protection zones and riparian buffer strips at water bodies in Russia and other countries are compared and analyzed. The technologies and specifics of the development of geoinformation system “Water Protection Zone and Riparian Buffer Strip of a Water Body” are demonstrated as applied to determining the boundary of the water protection zone and riparian buffer strip for the Uglich Reservoir. Assessment of the anthropogenic load onto a drainage basin within the water protection zone of the Uglich Reservoir and a method for geoecological zoning of its territory are considered as an example.     

太湖流域宜溧河地区水体水质状况及营养状态评价

宜溧河流域是太湖的主要集水流域,流域水体的水质状况及营养状态与太湖的水质状况与营养状态密切相关,本研究根据2000年12月14-15日以及2001年4月18-19日两次大规模的水质同步监测结果,对流域平原河网地区水体的水质状况及营养状态进行了系统综合的评价,评价结果表明：不管是平水期还是枯水期,河网水体的水质状况都较差,营养水平较高;在枯水期间,受多种因素的综合影响,水体的水质状况呈现恶化趋势,营养盐含量也有所升高。     

Physicochemical Properties of Bottom Sediments in Water Bodies in the Central and Southern Vietnam

Water Resources - The physicochemical characteristics of bottom sediments in inland water bodies in the Central and Southern Vietnam are presented for the first time, including particle-size...     

Some Problems of Reducing the Pollution of Water Bodies from Diffuse Sources

Water Resources - The role of diffuse pollution of water bodies in the formation of water quality in them is characterized. Some features of diffuse pollution, which are of importance for managing...     

Mathematical Modeling of the Effect of Protozoa on Methane Bacterial Oxidation in Water Bodies

A mathematical model is developed to simulate bacterial oxidation of CH₄ in the presence of protozoa. The model describes the vertical structure and time variations in the concentrations of dissolved CH₄, O₂, N-NH₄, and N-NO₃ in the water column. The model results correlate well with experimental data obtained on a laboratory assembly simulating near-bottom conditions, which form during stratification in dimictic freshwater bodies. Numerical experiments with the model were conducted to establish the relationships between the protozoa and methan-oxidizing bacteria. The principal mechanism for protozoa to control CH₄ oxidation was found to be the protozoa releasing reduced form of N.     

The Problem of Reducing the Diffuse Pollution of Water Bodies and Improving the Efficiency of Water Protection Programs

Water Resources - Regularities in the formation of diffuse pollution of water bodies are discussed as their understanding is required for the development of an adequate water-protection strategy....     

Impact of Annular Solar Eclipse of 15 January 2010 on the Atmospheric Boundary Layer Characteristics Over Thumba: A Case Study

On 15 January 2010, Thumba (8.5°N, 76.9°E) witnessed one of the longest known noontime annular solar eclipses (ASEs) spanning a period of about 7 min, centered at 1314 hours local time. In this research article, we present a case study on the behaviour of the atmospheric boundary layer characteristics and its vertical structure in response to this rare celestial event by making use of a suite of different in-situ instruments. During the peak period of the ASE, the incoming solar irradiance was dimmed by about 87% of its normal values, resulting in a significant reduction in the magnitudes of turbulent kinetic energy and surface-layer turbulent fluxes of heat and momentum. The intensity and vertical thickness of the sea/land breeze circulation cell over the study domain also weakened. However, the mixed layer heights determined from balloon-borne GPS Radiosonde did not show any appreciable changes. Analysis of vertical profiles of thermodynamic parameters in association with the wind direction during ASE indicated the formation of a double mixed layer between 700 and 1500 m and is attributed to horizontal advection of a different airmass at those altitudes.