Prominence Characteristics in 16th Activity Cycle

Digitization of the daily prominence sketches based on data from the global observational network of visual solar spectroscopes was performed for 1922–1934. More than 55000 prominences were distinguished. The results of analysis of distributions by area, height, and prominence location are presented. In addition, the prominence characteristics were compared to those obtained from more recent observations at the Kislovodsk Mountain Astronomical Station of Pulkovo Observatory. The distributions of prominence areas and heights are close to lognormal. The maximal height distribution corresponds to ~25–40 arcsecs. A second maximum also exists for prominence heights of ~70–90 arcsecs.     

Once More about Deep Caucasus Earthquakes

The upper crustal location of the foci of the Spitak earthquake of December 7, 1988, and its aftershocks is proved. It is demonstrated that the seismological network in Armenia and Georgia allowed unequivocal focal depth identification based on the kinematic data. The waveforms of all the Spitak earthquakes are typical of sources in the upper crust. It is noted that up to now, mantle earthquakes in the Caucasus have only been revealed in the Terek–Sunzha depression.     

Problem of transient turbulent convection and a semiempirical profile of turbulent heat exchange coefficient in freshwater bodies

A problem of convective cooling of both freshwater and saltwater lake is formulated. A transient one-dimensional turbulent model with variable layer depth is proposed to describe the process of freezing. The dependence of layer depth on time is determined by a universal equation describing the propagation of Deardorff convective layer. A combination of the main form of equations of Kolmogorov–Obukhov theory and available experimental data is shown to allow the construction of a universal profile of turbulent exchange coefficient, depending on the height.     

The instability of an electron beam with a finite radius in a boundless plasma

Within the framework of a linear theory, the instability of an electron beam with a finite radius in a cold magnetised boundless plasma is considered. It is shown that a finite beam dimension influences the generation of quasi-potential waves in two aspects: the perpendicular wave number is quantised so that the frequencies of the waves are subjected to strong selection; a new kind of instability appears due to wave energy losses by emission into surrounding space. Growth rate dependence of wave numbers and frequencies is investigated for typical parameters of experiments with electron beams in space.     

Biofacies of Upper Jurassic and Lower Cretaceous sediments of central West Siberia

Paleontological study of Upper Jurassic and Lower Cretaceous sediments recovered by boreholes in the Agan-Vakh and Nadym-Vengapur interfluves clarified environments of their deposition. As is shown, influx of siliciclastic material to central areas of the West Siberian sea basin varied through time. Taxonomic composition and ecological structure of nektonic and benthic fossil assemblages are analyzed and considered in terms of environmental factors such as hydrodynamics, aeration, temperature, and salinity of seawater.     

Lower Miocene sediments of central and western Ciscaucasia

The composition, structure, and geochemical properties of the thickest, relatively deep-water Lower Miocene sediments developed in western Ciscaucasia are considered. Of particular interest are materials from the Kuban superdeep borehole SG-12000 that recovered the uppermost layers of the Maikop Group at 3148–3961 m in the central Indol-Kuban Trough west of Krasnodar. However, the borehole did not penetrate the whole Lower Miocene section of the Maikop Group. Therefore, characteristics of the Maikop Group are supplemented with new materials from several other boreholes drilled in the eastern Kuban region. Thus, the typical (reference) Lower Miocene section of central and western Ciscaucasia has been sufficiently well described.     

A methodology for drought preparedness

Drought is a normal, recurrent feature of climate that affects virtually all countries to some degree. The number of drought-induced natural disasters has grown significantly since the 1960s, largely as a result of increasing vulnerability to extended periods of precipitation deficiency rather than because of an increase in the frequency of meteorological droughts. This increase in drought-induced natural disasters has resulted in a considerable growth of interest in drought mitigation and preparedness worldwide. The purpose of a national preparedness plan is to reduce societal vulnerability to drought through the adoption of preventive, anticipatory policies and programs. This paper describes a ten-step planning process that nations can follow to develop a drought preparedness plan. This process, originally developed in 1987, has been the basis of discussions at training seminars on drought preparedness for developing nations in Africa, Asia, and Latin America. It has also been adopted, with appropriate modifications, by state or provincial governments and by municipalities. The process is intended to be flexible so that governments can add, delete, or modify the suggested steps, as necessary.Published as Paper No. 10946, Journal Series, Nebraska Agricultural Research Division. The work reported here was conducted under Nebraska Agricultural Research Division Project 27-007. This material is based in part upon work supported by the National Science Foundation under Grant ATM-8704050.     

Efficiency of stimulating precipitation from convective clouds using salt powders

Comparative estimates of the efficiency of hygroscopic reagents for the seeding of convective clouds to obtain additional precipitation are performed based on numerical simulation. It is shown that the use of polydisperse salt powders has many benefits over other known hygroscopic reagents. The effect of seeding with salt powders manifests itself at mass concentrations of hygroscopic particles an order of magnitude less than when pyrotechnic flares are used. With salt-powder seeding, it is possible to obtain precipitation from warm convective clouds of moderate thickness from which precipitation does not typically fall. In this case the effect of “reseeding” of clouds, which can be observed in seeding with hygroscopic reagents having narrow size distributions of particles, does not reveal itself.