Aluminium in glacial meltwater demonstrates an association with nutrient export (Werenskiöldbreen,Svalbard)

The aluminium (Al) cycle in glacierised basins has not received a great deal of attention in studies of biogeochemical cycles. As Al may be toxic for biota, it is important to investigate the processes leading to its release into the environment. It has not yet been ascertained whether filterable Al (passing through a pore size of 0.45 μm) is incorporated into biogeochemical cycles in glacierised basins. Our study aims to determine the relationship between the processes bringing filterable Al and glacier‐derived filterable nutrients (particularly Fe and Si) into glacierised basins. We investigated the Werenskiöldbreen basin (44.1 km², 60% glacierised) situated in SW Spitsbergen, Svalbard. In 2011, we collected meltwater from a subglacial portal at the glacier front and at a downstream hydrometric station throughout the ablation season. The Al concentration, unchanged between the subglacial system and proglacial zone, reveals that aluminosilicate weathering is a dominant source of filterable Al under subglacial conditions. By examining the Al:Fe ratio compared with pH and the sulphate mass fraction index, we found that the proton source for subglacial aluminosilicate weathering is mainly associated with sulphide oxidation and, to a lesser degree, with hydrolysis and carbonation. In subglacial outflows and in the glacial river, Al and Fe are primarily in the forms of Al(OH)₄^‐ and Fe(OH)₃. The annual filterable Al yield (2.7 mmol m^‐2) was of a magnitude similar to that of nutrients such as filterable Fe (3.0 mmol m^‐2) and lower than that of dissolved Si (18.5 mmol m^‐2). Our results show that filterable Al concentrations in meltwater are significantly correlated to filterable and dissolved glacier‐derived nutrients (Fe and Si, respectively) concentrations in glaciers worldwide. We conclude that a potential bioavailable Al pool derived from glacierised basins may be incorporated in biogeochemical cycles, as it is strongly related to the concentrations and yields of glacier‐derived nutrients.     

Perseid meteor stream 1991 – 1993 from TV observations in Kiev

Some results of the double station television meteor observations provided in Kiev during the Perseid shower period in years 1991 – 1993 are presented. The dependence of the beginning hights of meteors on their initial velocities based on 57 best reduced double station meteors is constructed. Exceptionaly great beginning heights of meteors are discussed, as well as the exceptional case of a Perseid bolide.     

The study of atmospheric optical parameters according to multiyear photometric observations of the sun in crimea

We describe the construction of an SF-1 automatic sun photometer designed for determining the atmospheric optical parameters in the region of 372–1005 nm during year-round observations (monitoring), as well as an improved method of automatic data processing. Observations in Crimea (in Simferopol with an SF-1 photometer since 2001 and in Karadag with an M-83 standard sun photometer since 1972) are presented. Observation data are analyzed to demonstrate the intra-annual and interannual time dependences of the aerosol optical depths and Angstrom exponents for the atmosphere over Simferopol and Karadag. The considerable decrease in the aerosol optical depth (i.e., an increase in atmospheric transparency over Crimea) since 1993 due to an abrupt decrease in the anthropogenic load on the atmosphere as a result of the suspension of main industrial plants is an important finding.     

The spectrum of comet C/2009 R1 (McNaught) in 4140–5240 Å wavelength region

The spectroscopic observations of comet C/2009 R1 (McNaught) were carried out with the 2 m Zeiss-RCC Telescope of Pik Terskol Observatory operated by the International Center for Astronomical and Medico-Ecological Research (Ukraine, Russia). The Multi Mode Cassegrain spectrometer was used to obtain spectra of moderate spectral resolving power with a wavelength coverage from 4140 to 5240 Å. The spectrum is characterized by the extremely low continuum level and strong molecular features. 192 emission lines of C₂, CN, CH, NH₂, CO⁺, and CH⁺ have been identified by the comparison of the observed and theoretical spectra of the molecules. The ratios of the gas production rates of Q(C₂)/Q(CN)=1.32, Q(CH)/Q(CN)=0.49, and Q(NH₂)/Q(CN)=0.81 were derived using a Haser model.     

Dust tail of the active distant Comet C/2003 WT42 (LINEAR) studied with photometric and spectroscopic observations

We present the study of dust environment of dynamically new Comet C/2003 WT42 (LINEAR) based on spectroscopic and photometric observations. The comet was observed before and after the perihelion passage at heliocentric distances from 5.2 to 9.5 AU. Although the comet moved beyond the zone where water ice sublimation could be significant, its bright coma and extended dust tail evidenced the high level of physical activity. Afρ values exceeded 3000 cm likely reaching its maximum before the perihelion passage. At the same time, the spectrum of the comet did not reveal molecular emission features above the reflected continuum. Reddening of the continuum derived from the cometary spectrum is nonlinear along the dispersion with the steeper slop in the blue region. The pair of the blue and red continuum images was analyzed to estimate a color of the comet. The mean normalized reflectivity gradient derived from the innermost part of the cometary coma equals to 8% per 1000 Å that is typical for Oort cloud objects. However, the color map shows that the reddening of the cometary dust varies over the coma increasing to 15% per 1000 Å along the tail axis. The photometric images were fitted with a Monte Carlo model to construct the theoretical brightness distribution of the cometary coma and tail and to investigate the development of the cometary activity along the orbit. As the dust particles of distant comets are expected to be icy, we propose here the model, which describes the tail formation taking into account sublimation of grains along their orbits. The chemical composition and structure of these particles are assumed to correspond with Greenberg’s interstellar dust model of comet dust. All images were fitted with the close values of the model parameters. According to the results of the modeling, the physical activity of the comet is mainly determined by two active areas with outflows into the wide cones. The obliquity of the rotation axis of the nucleus equals to 20° relative to the comet’s orbital plane. The grains occupying the coma and tail are rather large amounting to 1 mm in size, with the exponential size distribution of a^−4.5. The outflow velocities of the dust particles vary from a few centimeters to tens of meters per second depending on their sizes. Our observations and the model findings evidence that the activity of the nucleus decreased sharply to a low-level phase at the end of April–beginning of May 2007. About 190 days later, in the first half of November 2007 the nucleus stopped any activity, however, the remnant tail did not disappear for more than 1.5 years at least.     

On accounting for temperature and pressure in determining the Rayleigh scattering in the earth’s atmosphere

We calculated the variations of Rayleigh optical depth with changes of pressure and temperature for three observation sites: Simferopol (φ = 44°57′N, λ = 34°8′E, h = 265 m above sea level), Nauchny (φ = 44°43′N, λ = 34°3′E, h = 583 m), and Ai-Petry meteorological station (φ = 44°24′N, λ = 34°6′E, h = 1180 m).     

Statistical analysis of plasma turbulence based on satellite magnetic field measurements

The probability density function (PDF) for the magnetic field fluctuations in the Earth’s magnetospheric tail on various time scales is investigated on the basis of Geotail satellite data for 1997, 1999, and 2000. The changes in the shape and parameters of the PDF for the periods before and during the current disruption have been studied. The changes in the height of the PDF maximum P(0) have been investigated as an evolution characteristic on various time scales. Two asymptotic regimes of P(0) characterized by different power laws have been found: the changes in the PDF maximum correspond to a Gaussian process on long time scales and to a Levy distribution on short time scales. The intersection of the two asymptotes corresponds to a time scale of about 1 s. The suggested approach is universal and can be used to analyze the fluctuations in other parameters of a different nature.     

Two spectra of turbulence of the sun

Observations obtained at the 70-cm vacuum tower telescope (VTT) at Izaña (Tenerife, Spain) are analyzed to show that turbulent processes in the solar photosphere have two distinct spectra of turbulence. The first is the well-known Kolmogorov spectrum, which describes plasmas with a zero mean magnetic field, and the second is the Kraichnan spectrum with a nonzero mean magnetic field. The transition from one spectrum type to another is found to occur at a scale of 3 Mm. This scale is consistent with the typical size of mesogranular structures, which indicates a transition to large-scale self-organizing magnetic structures.     

What risks matter? Public views about assisted migration and other climate-adaptive reforestation strategies

The world’s forests play an important role in regulating climate change through their capacity to sequester carbon. At the same time, they are also increasingly vulnerable to the impacts of climate change. In the western Canadian province of British Columbia, changes in temperature, precipitation, and disturbance regimes are already impacting forests. In response to these observed and anticipated changes, adapted reforestation practices are being developed and proposed as a means to help forest ecosystems adjust to changing climatic conditions. One such practice under consideration is assisted migration—planting species within or outside of the native historical range into areas that are anticipated to be climatically suitable in the future. We used a survey of British Columbia’s population at large (n?=?1923) to quantify levels of support for a range of potential reforestation options (including assisted migration) to adapt to climate change, and to explore what factors can help predict this support. Our findings reveal that the likely location of potential public controversy resides not with the potential implementation of assisted migration strategies per se, but rather with assisted migration strategies that involve movement of tree species beyond their native range.