3-D Structure of the Galactic Interstellar Matter: A Contribution from GAIA     

Jokūbas Sūdžius  Saulius Raudeliūnas  Arūnas Kučinskas  Audrius Bridžius  Vladas Vansevičius 《Astrophysics and Space Science》2002,280(1-2):109-114

We investigate the possibilities for tracing interstellar extinction with the ESA's astrometric space mission GAIA. The analysis is based on detailed simulations of the GAIA photometry, which are used to derive the distribution of interstellar matter in a modelled Galaxy. We find that `small' diffuse clouds (diameter D = 4 pc, E <sub>B-V</sub> = 0.06) will be easily traced with GAIA up to the distances of ∼ 800 pc. `Large' diffuse interstellar clouds (D = 10 pc, E _B-V = 0.13) will be located up to the distances of ∼ 2.5 kpc. This holds for the reddening tracers of spectral types O – K2 brighter than V = 17. Inmost cases, due to their low spatial density, the early type stars (O– A2) cannot provide reliable information about the distribution of interstellar matter. None of the reddening tracers measured by GAIA will provide reliable identification of the individual interstellar clouds beyond the distances of ∼ 3 kpc. Therefore, we conclude that the information available from photometric observations will be not sufficient for the detailed reconstruction of the 3-D distribution of Galactic interstellar matter. It is therefore extremely important to define the new strategies which would allow to combine all the available information, including the earlier space- and/or ground-based investigations, together with the information which will be provided by GAIA itself (parallaxes, E _B-V etc.). This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Book reviews     

M. Doležalová  K. Drozd  A. Jupe 《Rock Mechanics and Rock Engineering》1993,26(1):81-85

  相似文献   

On the Tolerances of Filters for GAIA Medium Band Photometric System     

Algirdas Kazlauskas  Vladas Vansevičius  Audrius Bridžius  Ramutis Drazdys  Romualdas Kalytis 《Astrophysics and Space Science》2002,280(1-2):57-62

We investigate the effects arising from the filter transmission curve differences across the filter area in the 3G medium-band photometric system proposed for GAIA. We discuss the accuracy of the transformations to the standard photometric system and the precision of the determination of physical parameters for various types of stars using the 4-D classification procedure. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Seismology of sunspot atmospheres     

Y. D. Žugžda  V. Locāns  J. Staude 《Solar physics》1983,82(1-2):369-378

The present work deals with the theory of oscillations with periods of about 3 min observed in the chromosphere above sunspot umbrae. The model of these oscillations (slow mode magneto-acoustic waves trapped in a chromospheric resonant cavity) provides an independent method of checking empirical models of the chromosphere above sunspots. Making use of this method, we investigate sunspot models which have been derived from spectroscopic data; the calculated periods of the oscillations fit well the observed periods.  相似文献   

Fundamental stellar parameters derived from the evolutionary tracks     

V. Straižys  G. Kuriliene 《Astrophysics and Space Science》1981,80(2):353-368

The surface gravities and radii of stars are calculated for different MK spectral types using the masses of stars determined from their evolutionary tracks in the HR diagram and the most reliable values of effective temperatures and absolute bolometric magnitudes. MK spectral types are calibrated in absolute visual magnitudes using the studies ofM _v published since 1965. The calibration of MK types in temperatures is based on the newest investigations including the results both from the ultraviolet and the infrared. The obtained masses, gravities, and the mass-luminosity relationship show reasonable agreement with independent observational data.  相似文献   

Constraining genesis and geotectonic setting of metavolcanic complexes: a multidisciplinary study of the Devonian Vrbno Group (Hrubý Jeseník Mts., Czech Republic)     

Vojtěch Janoušek  Jaroslav Aichler  Pavel Hanžl  Axel Gerdes  Vojtěch Erban  Vladimír Žáček  Vratislav Pecina  Marta Pudilová  Kristýna Hrdličková  Petr Mixa  Eliška Žáčková 《International Journal of Earth Sciences》2014,103(2):455-483

The low-grade metavolcanic/volcanosedimentary complex of the Devonian Vrbno Group (Silesicum, NE Bohemian Massif, Czech Republic) occurs in two ~NE–SW trending belts, separated by tectonic slices of Cadomian metagranitic paraautochton. (1) The basic–intermediate lavas of the calc-alkaline Western Volcanic Belt came from a moderately depleted mantle $ \left( {\varepsilon_{\text{Nd}}^{370} \sim + 3} \right) $ . Rare rhyolites (374.0 ± 1.7 Ma: 2σ, LA–ICP–MS U–Pb Zrn) were derived most likely from immature crust or by extensive fractionation of primary basaltic melts. The rock association is interpreted as a vestige of a deeply dissected continental arc. (2) The Eastern Volcanic Belt consists mainly of (nearly) contemporaneous (371.0 ± 1.4 Ma) felsic alkaline lavas with high HFSE contents, as well as high Ga/Al and Fe/Mg ratios, typical of within-plate igneous setting. The petrology and Nd–Sr isotopic data point to a high-T anatexis of a young metagranitic crust, resembling the Cadomian (Brunovistulian) basement, in a back-arc setting. The attenuated Brunovistulian lithosphere could have partially melted by the heat provided by the upwelling asthenosphere and/or underplating basic magma. (3) Finally, the region was penetrated by numerous subalkaline, MORB/EMORB-like dolerite sheets—a hallmark of the considerable crustal thinning.  相似文献   

A combined statistical approach for evaluation of the effects of land use,agricultural and urban activities on stream water chemistry in small tile-drained catchments of south Bohemia,Czech Republic   总被引：1，自引：0，他引：1  

Petr Fučík  Pavel Novák  Daniel Žížala 《Environmental Earth Sciences》2014,72(6):2195-2216

This work evaluates the changes of nitrate-nitrogen (NO₃-N), ammonium-nitrogen (NH₄-N), total phosphorus (P) and chemical oxygen demand (COD) concentrations in stream waters as related to the land use/land cover (LULC) alterations within eight small (5–39 km²) tile-drained catchments in the southern part of The Czech Republic in the period 1993–2010, when massive grassing of arable land took place. The robust tools of seasonal Mann–Kendall trend test and LOcally WEighted Scatterplot Smoothing methods were employed to reveal trends of the monitored parameters with adjustment to hydrology. Using principal component analysis and multiple regressions, statistically significant factors with highest impacts on the assessed water quality parameters were identified. Besides indicators of LULC changes in the catchments and their various zones, information of built tile drainage systems were used along with factors reflecting point pollution sources such as the population number, sewerage type and proximity to a watercourse, effectiveness of wastewater treatment, and number of livestock units. The change in LULC was essential only for NO₃-N concentrations, when grassing of arable land, presence of water ponds, areas of permanent cultures and also areas of drained land explained up to 90.6 % NO₃-N variability and nitrate-nitrogen concentrations showed a significantly decreasing trend in all monitored catchments during the evaluated period. LULC changes within infiltration vulnerable zones were discovered as less important for the assessed water quality parameters compared to LULC changes in the whole catchment area. However, for NH₄-N, P and COD, the results did not enable a definite quantification of the effects of LULC changes. The influence of non-point pollution sources on these parameters was revealed as uncertain and was heavily overshadowed by point sources, in particular by wastewater management, and livestock numbers, although the proportion of arable land in tile drainage subcatchments was discovered fundamental in case of the COD. The increasing numbers of livestock, population, and changes in sewage treatment led in some catchments to significant worsening of water quality. Achieved findings may be critical for supporting water quality policy and management decisions.  相似文献   

Interannual variability of air temperature inversions in ice-free area of northern James Ross Island,Antarctica     

Ambrožová  Klára  Láska  Kamil  Matějka  Michael  Reuder  Joachim 《Theoretical and Applied Climatology》2022,148(3-4):967-983

Theoretical and Applied Climatology - Air temperature inversions are common features in Antarctica, especially in the interior where they are observed nearly year-round. Large temporal variability...  相似文献   

Observational Investigation of the Statistical Properties of Surface-Layer Turbulence in a Suburban Area of São Paulo,Brazil: Objective Analysis of Scaling-Parameter Accuracy and Uncertainties     

da Silveira  Lucas Cardoso  de Oliveira  Amauri Pereira  Sánchez  Maciel Piñero  Codato  Georgia  Ferreira  Maurício Jonas  Marques Filho  Edson Pereira  Božnar  Marija Zlata  Mlakar  Primož 《Boundary-Layer Meteorology》2022,185(2):161-195

Boundary-Layer Meteorology - Statistical properties of turbulence, specifically variances of velocity components, temperature, water vapor, and carbon dioxide densities, are observationally...  相似文献   

Global change revealed by palaeolimnological records from remote lakes: a review   总被引：1，自引：0，他引：1  

Jordi Catalan  Sergi Pla-Rabés  Alexander P. Wolfe  John P. Smol  Kathleen M. Rühland  N. John Anderson  Jiři Kopáček  Evžen Stuchlík  Roland Schmidt  Karin A. Koinig  Lluís Camarero  Roger J. Flower  Oliver Heiri  Christian Kamenik  Atte Korhola  Peter R. Leavitt  Roland Psenner  Ingemar Renberg 《Journal of Paleolimnology》2013,49(3):513-535

Over recent decades, palaeolimnological records from remote sites have provided convincing evidence for the onset and development of several facets of global environmental change. Remote lakes, defined here as those occurring in high latitude or high altitude regions, have the advantage of not being overprinted by local anthropogenic processes. As such, many of these sites record broad-scale environmental changes, frequently driven by regime shifts in the Earth system. Here, we review a selection of studies from North America and Europe and discuss their broader implications. The history of investigation has evolved synchronously with the scope and awareness of environmental problems. An initial focus on acid deposition switched to metal and other types of pollutants, then climate change and eventually to atmospheric deposition-fertilising effects. However, none of these topics is independent of the other, and all of them affect ecosystem function and biodiversity in profound ways. Currently, remote lake palaeolimnology is developing unique datasets for each region investigated that benchmark current trends with respect to past, purely natural variability in lake systems. Fostering conceptual and methodological bridges with other environmental disciplines will upturn contribution of remote lake palaeolimnology in solving existing and emerging questions in global change science and planetary stewardship.  相似文献