Applying an Automatic Image-Processing Method to Synoptic Observations

We used an automatic image-processing method to detect solar-activity features observed in white light at the Kislovodsk Solar Station. This technique was applied to automatically or semi-automatically detect sunspots and active regions. The results of this automated recognition were verified with statistical data available from other observatories and revealed a high detection accuracy. We also provide parameters of sunspot areas, of the umbra, and of faculae as observed in Solar Cycle 23 as well as the magnetic flux of these active elements, calculated at the Kislovodsk Solar Station, together with white-light images and magnetograms from the Michaelson Doppler Imager onboard the Solar and Heliospheric Observatory (SOHO/MDI). The ratio of umbral and total sunspot areas during Solar Cycle 23 is ≈?0.19. The area of sunspots of the leading polarity was approximately 2.5 times the area of sunspots of the trailing polarity.     

Gibbsite and Boehmite in Weathering Crusts of Different Ages Affected by Lateritization: Location and Formation

Doklady Earth Sciences - The main source of aluminum is bauxite ores and their basic mineral components gibbsite Al(OH)3 and boehmite AlO(OH). Alumina Al2O3 is formed by various methods of...     

Two Genetic Types of Bauxites of the Central Deposit (Siberian Platform) and a Rare Metal Mineralization

Doklady Earth Sciences - The Central bauxite deposit on the territory of the Russian Federation is a unique geological object. It hosts both primary lateritic bauxites and products of their...     

The sector structure of the active longitudes in solar cycles

The longitudinal distributions of the polar faculae, bright K Ca⁺ points, and sunspot areas have been investigated in three-year intervals at the minima and maxima of the last five solar cycles in the rotation system which corresponds to the background magnetic field:T = 27.23 days (Mikhailutsa, 1994b). It has been shown that there were three specific features of the polar faculae and bright K Ca⁺ point longitudinal distributions: (1) The longitudes of maxima and minima of the distributions were approximately the same in the last five solar cycles. (2) There were predominantly two opposite longitudinal maxima and two opposite longitudinal minima in the distributions of each hemisphere. (3) The distributions of the northern and southern hemispheres were in opposite phase. The extremes of the sunspot area longitudinal distributions were preferentially between the longitudes of the polar facular extremes. The period of the sector structure rotation was defined more precisely:T = 27.227 ± 0.003 days. The results found can serve as an indication that there is a global foursector structure seated in the solar interior which plays a visible role in the polar facular and sunspot distributions.     

Evidence for moving features in the corona from emission line profiles observed during eclipses

Using the line profiles of [Fe x] 6374 å and [Fe XIV] 5303 å emission lines observed during five total solar eclipses, we address the problem whether the solar corona is static or contains moving features. Many of the profiles of both emission lines have complicated shapes, which we interpret as an evidence for the existence of many, small, moving features in the corona. The line-of-sight velocities observed by other investigators (e.g. Desai, Chandrasekhar & Angreji 1982) also support this view. On the other hand, about 15 recent interferometric and multislit investigations of coronal emission lines have not shown evidence of moving elements. We suggest that this is due to insufficient spatial resolution.     

Do polar faculae on the sun predict a sunspot cycle?

The paper reports the results of the analysis of the data on polar faculae for three solar cycles (1960–1986) at the Kislovodsk Station of the Pulkovo Observatory and on polar bright points in Ca ii K line for two solar cycles (1940–1957) at the Kodaikanal Station of the Indian Institute of Astrophysics. We have noticed that the monthly numbers of polar faculae and polar bright points in Ca ii K line and monthly sunspot areas in each hemisphere of the following solar cycle have a correlation with each other. A new cycle of polar faculae and polar bright points in the Ca ii K line begins after the polar magnetic field reversal. We find that the smaller the period between the ending of the polar field reversal and the beginning of a new sunspot cycle is, the more intense is the cycle itself. The intensity of the forthcoming solar cycle (cycle 22) and the periods of strong fluctuations in activity expected in this cycle are also discussed.     

Ratio between erosion and tectonic processes in platforms and mountainous regions

The paper discusses changes in the structure of river valleys under action of Coriolis forces, directed migration of river channels toward the right-side banks regardless of river orientation, dimensions, and water abundance. The values of lateral and bottom erosion in river valleys are compared with the rates of modern deformations in platforms and mountainous regions. This phenomenon is to be taken into consideration when interpreting lineaments and other topographic features as tectonic elements.     

Polar faculae and sunspot cycles

The monthly number of polar faculae of the Sun were determined from white-light images at spectral band (eff) = (4100 ± 200) Å obtained at the Kislovodsk Solar Station during 1960–1994. Corrected monthly numbers were obtained with the help of the visibility function. The level of polar activity larger than 1 above the monthly running mean was calculated, and the relation between the polar faculae and sunspot cycle was studied. We confirmed earlier results (Makarov and Makarova, 1987) that the monthly number of polar faculae, NPF _m (t) correlates with the monthly sunspot area A _m (Sp)(t + T) with a time shift T 6 yr. The new polar faculae cycle began in the middle of 1991. Peculiarities of the first part of sunspot cycle 23 are discussed.Guest scientist with the University of Arizona and Zetetic Institute. Tucson, Arizona 85719, U.S.A.     

MODIS-NDVI-based mapping of the length of the growing season in northern Fennoscandia

Northern Fennoscandia is an ecologically heterogeneous region in the arctic/alpine-boreal transition area. Phenology data on birch from 13 stations and 16-day MODIS-NDVI composite satellite data with 250 m resolution for the period 2000 to 2006 were used to map the growing season. A new combined pixel-specific NDVI threshold and decision rule-based mapping method was developed to determine the onset and end of the growing season. A moderately high correlation was found between NDVI data and birch phenology data. The earliest onset of the growing season is found in the narrow strip of lowland between the mountains and the sea along the coast of northern Norway. The onset follows a clear gradient from lowland to mountain corresponding to the decreasing temperature gradient. In autumn, the yellowing of the vegetation shows a more heterogeneous pattern. The length of the growing season is between 100 and 130 days in 55% of the study area.     

Coherent Structures in the Atmospheric Surface Layer under Stable and Unstable Conditions

Simultaneous measurements of the instantaneous values of absolute temperatureat seven heights within the lower 36 m of the atmospheric boundary layer underdifferent stability conditions were carried out, accompanied by measurements ofthe wind velocity components at two levels and of solar radiation flux at the surface.The data obtained allow one to investigate individual convective cells known ascoherent structures (CS). Outside the CS, i.e., during quiet periods, an instanttemperature profile is in close agreement with the dry-adiabatic lapse rate, butwithin CS the temperature changes much faster with height, and the shape ofthe profile varies significantly.A method was developed to transform temperature records from sensors atseveral heights into an other form, namely, into temporal variations of theheights of isothermal surfaces. Since coherent structures were found to advectwith the mean wind velocity, these temporal height variations may be transformedinto the spatial ones, i.e., into the xoz-plane section of the temperature field.In such a pictorial presentation coherent structures look like asymmetric columnsof heat, penetrating the whole atmospheric surface layer.Coherent structures also exist in the stable stratified surface layer, but they have aninverse asymmetry and occupy only the lower several metres. Wavelike activitydominates in the upper part of the stable surface layer.The characteristic time of surface-layer adjustment to the rapid changes of solarradiation (due to cloud shadows or cloud gaps) was found to be on the order ofone minute. Such a time interval is required for coherent structure to reach the topof surface layer.