Climate Change in the Urals,Russia, Inferred from Borehole Temperature Data

Borehole temperatures in the central and south Urals were analysed for the past ground surface temperature (GST) signal. 31 highquality temperature logs were selected for this purpose and inverted with algorithms based on the generalised least squares theory. The signal to noise ratio was improved by averaging the results of individual borehole inversions. No distinct regional trends were found in the studied region except for some indications of more pronounced warming in the south. The mean GST history (GSTH) was characterised by cooling down to –0.6 °C in the 18th century and subsequent warming to 0.5 °C above the longterm mean at the beginning of this century, and to 1 – 1.5 °C by 1980. The stability of the mean GSTH was tested in dependence on the number of holes used for the averaging. It showed that any subset of 15 holes yielded a GSTH similar to that obtained from the whole set. A surface air temperature (SAT) time series comprising the period 1832 – 1989 was combined from 17 meteorological records. Its least squares warming rate of 1.1 °C per 100 years is somewhat higher than that of the GST (0.7 – 0.8°C/100 years) in the same period.     

Real-time raster projection for web maps

The virtual globe is the default visualization for Digital Earth applications, but it can only show one half of the Earth. This article introduces user-adjustable, on-the-fly projection of georeferenced raster images for web mapping and web GIS applications. This technique allows users to center a map on arbitrary locations, while still seeing the entire Earth surface. Modern web mapping libraries can apply map projection transformations to vector data in the browser, but they do not currently support the projection of raster images at interactive frame rates. We use the cross-platform WebGL (Web Graphics Library) graphics pipeline for hardware-accelerated projection of raster data in web browsers. Two algorithmic techniques – inverse per-fragment projection, and combined forward per-triangle and inverse per-fragment projection – for georeferenced raster imagery are documented. The resulting raster maps combine the ease of use and flexibility of interactive virtual globes with the ability to show the entire Earth. The adjustable projection of raster imagery allows users to observe global phenomena that are difficult to visualize on virtual globes or traditional maps with static projections.     

Circumstellar dust and related phenomena at phase 0.8 in Miras

SeveralM-type Mira variables (o Cet, RT Cyg) exhibit a sudden polarization increase near phaseP=0.8 of visual light period, whereas the position angle of the linearly polarized component remains almost unchanged. The degree of polarization is observed to be high (6%) in the violet and blue region and to decrease slowly toward the infrared. In connection with appearance of the 10 m band this indicates the presence of circumstellar silicate grains of diameters varying between 100 nm and 1 m.In dirty silicate particles, i.e. SiO₂ + metal ion admixture, the colour centres can be activated by absorbing of energetic photons, which results in increasing imaginary part of the refractive index. As showed by Svat of (1980), this mechanism can explain the polarization rise of light transmitted through a layer of aligned nonspherical dirty silicate glassy grains. From the appearance of the Balmer emission lines in the lower atmospheric layer, SiO maser activity disruption and the other phenomena occuring atP0.8 it is concluded, that the source of the activating short wavelength radiation can lie in the ionization front ahead of the expanding shock wave (assumed in the model of Miras atmosphere by Hinkle and Barnes, 1979) and in other eruptive phenomena in Miras. The same mechanism can be effective in Nova outbursts, RS CVn flares and T Tau sudden luminosity variations. The role of magnetic field in the Miras atmosphere is discussed.     

Method of anthropoecological stabilization of landscape and its interpretation

The study deals with the theoretical approach to anthropoecological stabilization of landscape (ASL). It describes a method consisting of four stages including detailed differentiation from the viewpoint of aim, objectives of investigation, and means of evaluation and processing. Application of the method requires to provide: the preparatory, analytical ground — I. stage (analytical part), the structural — functional evaluation of the territory under solution — II. stage (analytical-synthetical part), the solution of ecooptimization relations and bonds by way of material and energy flows — III. stage (regulative part), the monitoring and signalling activities, determination of all-system biogeoindications — IV. stage (ensuring part).The results are exemplified by application to model territories in South Bohemia region.     

Multi-thermal observations of newly formed loops in a dynamic flare

The dynamic flare of 6 November, 1980 (max 15:26 UT) developed a rich system of growing loops which could be followed in H for 1.5 hr. Throughout the flare, these loops, near the limb, were seen in emission against the disk. Theoretical computations of deviations from LTE populations for a hydrogen atom reveal that this requires electron densities in the loops close to, or in excess of 10¹² cm ^-3. From measured widths of higher Balmer lines the density at the tops of the loops was found to be 4 x 10¹² cm ^-3 if no non-thermal motions were present, or 5 × 10¹¹ cm ^-3 for a turbulent velocity of ~ 12 km s ^-1.It is now general knowledge that flare loops are initially observed in X-rays and become visible in H only after cooling. For such a high density, a loop would cool through radiation from 10⁷ to 10⁴ K within a few minutes so that the dense H loops should have heights very close to the heights of the X-ray loops. This, however, contradicts the observations obtained by the HXIS and FCS instruments on board SMM which show the X-ray loops at much higher altitudes than the loops in H. Therefore, we suggest that the density must have been significantly lower when the loops were formed and that the flare loops were apparently both shrinking and increasing in density while cooling.NAS/NRC Research Associate, on leave from CNIE, Argentina.Operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation. Partial support for the National Solar Observatory is provided by the USAF under a Memorandum of Understanding with the NSF.     

Metamorphic inheritance of Rheic passive margin evolution and its early‐Variscan overprint in the Teplá‐Barrandian Unit,Bohemian Massif

Rift‐related regional metamorphism of passive margins is usually difficult to observe on the surface, mainly due to its strong metamorphic overprint during the subsequent orogenic processes that cause its exposure. However, recognition of such a pre‐orogenic evolution is achievable by careful characterization of the polyphase tectono‐metamorphic record of the orogenic upper plate. A multidisciplinary approach, involving metamorphic petrology, P–T modelling, structural geology and in situ U‐Pb monazite geochronology using laser‐ablation split‐stream inductively coupled plasma mass spectrometry, was applied to unravel the polyphase tectono‐metamorphic record of metapelites at the western margin of the Teplá‐Barrandian domain in the Bohemian Massif. The study resulted in discovery of three tectono‐metamorphic events. The oldest event M1 is LP–HT regional metamorphism with a geothermal gradient between 30 and 50 °C km^?1, peak temperatures up to 650 °C and of Cambro‐Ordovician age (c. 485 Ma). The M1 event was followed by M2‐D2, which is characterized by a Barrovian sequence of minerals from biotite to kyanite and a geothermal gradient of 20–25 °C km^?1. D2‐M2 is associated with a vertical fabric S2 and was dated as Devonian (c. 375 Ma). Finally, the vertical fabric S2 was overprinted by a D3‐M3 event that formed sillimanite to chlorite bearing gently inclined fabric S3 also of Devonian age. The high geothermal gradient of the M1 event can be explained as the result of an extensional, rift‐related tectonic setting. In addition, restoration of the deep architecture and polarity of the extended domain before the Devonian history – together with the supracrustal sedimentary and magmatic record – lead us to propose a model for formation of an Ordovician passive continental margin. The subsequent Devonian evolution is interpreted as horizontal shortening of the passive margin at the beginning of Variscan convergence, followed by detachment‐accommodated exhumation of lower‐crustal rocks. Both Devonian shortening and detachment occurred in the upper plate of a Devonian subduction zone. The tectonic evolution presented in this article modifies previous models of the tectonic history of the western margin of the Teplá‐Barrandian domain, and also put constraints on the evolution of the southern margin of the Rheic ocean from the passive margin formation to the early phases of Variscan orogeny.