Relationship between the contrast of coronal holes and parameters of the solar wind streams

It is shown that the contrast of coronal holes (CH) determines the speed of the solar wind streams to the same extent as their area does. We analyzed more than 400 images obtained in the λ284 Å channel. The time interval under examination covers about 1500 days in the declining phase of cycle 23 (from 2002 to 2006). We considered all coronal holes recorded during that interval in the absence of coronal mass ejections (CME). Comparison was also made with some other parameters of the solar wind (e.g., density, temperature, and magnetic field). A fairly high correlation (0.70–0.89) was obtained with the velocity, especially during the periods of moderate activity, which makes this method useful for everyday forecast. The ratio of CH brightness to the mean brightness of the disk in the λ284 Å channel is about 25%.     

The application of GPR to barrier-lagoon sedimentation study in Boao of Hainan Island

Sedimentary successions and internal structure of the coastal barrier-lagoon system of Boao, eastern Hainan Island were studied through utilizing data from test holes and trenches and ground-penetrating-radar (GPR) profiles. During late Pleistocene, fluvial and delta plains developed over an unevenly eroded bedrock during low sea level stand, followed by the formation of littoral and lagoon facies and defined coastal barrier-lagoon-estuary system during the post-glacial uppermost Pleistocene-lower Holocene eustatic rise of the sea level, and the upper Holocene high stand. GPR results show that Yudaitan, a sandy coastal bar backed by a low-laying land (shoal) just east of the active lagoon, is a continuous, parallel and slightly-wavy reflectors indicating homogeneous sandy or sandy gravel sediments, and inclined reflectors partly caused by progradation and accumulation of beach sand and gravel. Quasi-continuous, hummocky and chaotic reflectors from the shoal of Nangang village correspond to mixed accumulation of sands and clay. This research indicates the GPR is a non-intrusive, rapid, and economical method for high-resolution profiling of subsurface sediments in sandy gravelly coast.     

Bacterial communities in Hoito Gol hot spring,Eastern Sayan,and the ecologic-geological conditions of their development

Hoito Gol hot spring of weakly mineralized warm (36–29°C) neutral and partly alkaline nitrogen-carbon dioxide waters belongs to the hydrogeological structure of the actively water-flooded fault marked by the Sentsy River at the southwestern termination of the Baikal rift system. The spatiotemporal evolution of the major parameters of the underground aqueous ecosystem of this spring is controlled mainly by geological and geodynamic factors, whereas the parameters of the surface system are determined mostly by bacterial factors. Variations in these factors are correlated with changes in the composition, structure, and spatial distribution of the bacterial communities.     

Forecasting volcanic eruptions from seismic data

An increase in cumulative seismic strain release from volcanic earthquakes prior to eruptions of Bezymyanniy Volcano in 1955–1961 and Sheveluch Volcano in 1964 in Kamchatka, and of Tokachi-dake Volcano on Hokkaido Island in 1962 occurred in accordance with a hyperbolic law. The relationship obtained may be universal for andesite volcanoes. Knowing the law of the increase of cumulative seismic strain and carrying out continueus observations of the seismic regime of andesite voleanoes makes it possible to prediet time and energy of eruptions. By observation of volcanic earthquakes it is also possible to predict the place and time of the occurrence of lateral craters.     

The anisotropy of cosmic ray arrival directions around 10 eV

Anisotropy in the arrival directions of cosmic rays with energies above 10¹⁷ eV is studied using data from the Akeno 20 km² array and the Akeno Giant Air Shower Array (AGASA), using a total of about 114 000 showers observed over 11 years. In the first harmonic analysis, we have found a strong anisotropy of 4% around 10¹⁸ eV, corresponding to a chance probability of 0.2% after taking the number of independent trials into account. with two-dimensional analysis in right ascension and declination, this anisotropy is interpreted as an excess of showers near the directions of the Galactic Center and the Cygnus region.     

Investigation of magnetic fields in solar active regions

The magnetic-field structure in solar active regions outside spots is studied. The line-of-sight fields were measured using the new Crimean digital magnetograph in three spectral lines—Fe I 5253 Å, Fe II 5234 Å, and Ti I 5193 Å. Observations in the Fe II 5234 Å line indicate systematically higher field strengths than those in the Fe I 5253 Å line. The magnetic fluxes in 2″ elements are ～4.3×10¹⁸ Mx, ～4.6×10¹⁸ Mx, and ～6.2×10¹⁸ Mx according to the Fe I 5253 Å, Ti I 5193 Å, and FeII 5234 Å observations, respectively. Elements 2″–8″ in size make the largest contribution to the magnetic fluxes of active regions outside spots.     

El Niño-Southern Oscillation: Related Probabilities of Fatalities from Natural Perils in Australia

The interannual variability of flood, bushfire andheatwave fatality data for eastern Australia duringthe period 1876–1991 was analysed with respect to thephase of the El Niño-Southern Oscillation (ENSO)and the associated values of the Southern OscillationIndex (SOI). Heatwaves were found to be the mostserious peril in terms of the total number offatalities, while floods ranked first in the fatalityevent day statistics. None of the three monthly(absolute value) fatality data sets showed significantcorrelations with the corresponding values of the SOI,while the correlation analysis of annual (July toJune) data led to significant correlation coefficientsof 0.5 for floods and -0.3 for bushfires. AdditionalSOI value-related classification of the standardisedfatality event days into several ENSO categoriesconfirmed the correlation trends by showing anincrease (decrease) in the standardised bushfire(flood) fatality event day frequencies with increasingvalues of the SOI. In contrast to that, thestandardised heatwave fatality data showed aninconclusive distribution pattern, which hints at theinfluence of other possible factors (such as airpollution) on heatwave-related fatality numbers.The results of a risk assessment analysis have shownthat the probability of reaching the mean annualnumber of flood-fatality event days is roughly fourtimes higher during La Niña seasons (80%) thanthe corresponding probability associated with ElNiño periods (18%). The correspondingprobabilities associated with the mean bushfire andheatwave fatality event days displayed a reversedpattern, with the probabilities of El Niño-relatedyears being roughly twice as high as those associatedwith La Niña seasons (70% and 30% for bushfires,and 60% and 25% for heatwaves, respectively).Further probability calculations performed on thetotals of fatalities from all three perils identifiedthe La Niña years as potentially the mostdangerous in terms of suffering fatalities from theseperils. Furthermore, they highlighted the significantdifferences between the means of fatality event daynumbers recorded during years of extreme SOI values(9.8 for La Niña, and 9.1 for El Niño seasons)and those marked by near-zero SOI values (6.6). Themajor reason for the increase in risk associated withextreme ENSO phases was the higher variability ofthese perils during the respective seasons.     

Variations in the Orbital Periods of Eclipsing Binaries RY Aqr,AK Vir,and AX Vul

Astronomy Reports - Variations in the orbital period of eclipsing binaries RY Aqr, AK Vir, and AX Vul are studied. It is shown these variations can be represented with equal accuracy in two ways:...     

Multi-Stage Magmatic-Hydrothermal Sulfide-PGE Mineralization of the Khudolaz Complex (South Urals)

Geology of Ore Deposits - For the first time, from the standpoint of magmatism and subsequent hydrothermal–metasomatic alteration, sulfide and platinum-metal mineral assemblages of rocks of...