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71.
Existing and planned radiotelescopes working in the millimetre (mm) and sub-millimetre wavelengths range provide the possibility to be used for atmospheric line observations. To scrutinize this potential, we outline the differences and similarities in technical equipment and observing techniques between ground-based aeronomy mm-wave radiometers and radiotelescopes. Comprehensive tables summarizing the technical characteristics of existing and future (sub)-mm radiotelescopes are given. The advantages and disadvantages using radiotelescopes for atmospheric line observations are discussed. In view of the importance of exploring the sub-mm and far-infrared wavelengths range for astronomical observations and atmospheric sciences, we present model calculations of the atmospheric transmission for selected telescope sites (DOME-C/Antarctica, ALMA/Chajnantor, JCMT and CSO on Mauna Kea/Hawaii, KOSMA/Swiss Alpes) for frequencies between 0 and 2000 GHz () and typical atmospheric conditions using the forward model MOLIERE (version 5). For the DOME-C site, the transmission over a larger range of up to 10 THz () is calculated in order to demonstrate the quality of an Earth-bound site for mid-IR observations. All results are available on a dedicated webpage. 相似文献
72.
James M. Eaton Nicola M. McGoff Kenneth A. Byrne Paul Leahy Ger Kiely 《Climatic change》2008,91(3-4):317-334
Using both historic records and CORINE land cover maps, we assessed the impact of land cover change on the stock of soil organic carbon (SOC) in the Republic of Ireland from 1851 to 2000. We identified ten principal land cover classes: arable land, forest, grassland, heterogeneous agricultural areas/other, nonvegetated semi-natural areas, peatland, suburban, urban, water bodies, and wetland. For each land cover class, the SOC stock was estimated as the product of SOC density and land cover area. These were summed to calculate a national SOC budget for the Republic of Ireland. The Republic of Ireland’s 6.94 million hectares of land have undergone considerable change over the past 150 years. The most striking feature is the decrease in arable land from 1.44 million ha in 1851 to 0.55 million ha in 2000. Over the same time period, forested land increased by 0.53 million ha. As of 2000, agricultural lands including arable land (7.85%), grassland (54.33%), and the heterogeneous agricultural areas/other class (7.91%) account for 70.09% of Irish land cover. We estimate that the SOC stock in the Republic of Ireland, to 1 m depth, has increased from 1,391 Tg in 1851 to 1,469 Tg in 2000 despite soil loss due to urbanization. This increase is largely due to the increase of forested land with its higher SOC stocks when compared to agricultural lands. Peatlands contain a disproportionate quantity of the SOC stock. Although peatlands only occupy 17.36% of the land area, as of 2000, they represented 36% of the SOC stock (to 1 m depth). 相似文献
73.
G. Diego Gatta Nicola Rotiroti Martin Fisch Thomas Armbruster 《Physics and Chemistry of Minerals》2010,37(4):227-236
Elastic behavior and pressure-induced structural evolution of synthetic boron-mullite “Al5BO9” (a = 5.678(2) Å, b = 15.015(4) Å and c = 7.700(3) Å, space group Cmc21, Z = 4) were investigated up to 7.4 GPa by in situ single-crystal X-ray diffraction with a diamond anvil cell under hydrostatic conditions. No phase transition or anomalous compressional behavior occurred within the investigated P range. Fitting the P–V data with a truncated second-order (in energy) Birch-Murnaghan Equation-of-State (BM-EoS), using the data weighted by the uncertainties in P and V, we obtained: V 0 = 656.4(3) Å3 and K T0 = 165(7) GPa (β V0 = 0.0061(3) GPa?1). The evolution of the Eulerian finite strain versus normalized stress (f E–F E plot) leads to an almost horizontal trend, showing that a truncated second-order BM-EoS is appropriate to describe the elastic behavior of “Al5BO9” within the investigated P range. The weighted linear regression through the data points gives: F E(0) = 159(11) GPa. Axial compressibility coefficients yielded: β a = 1.4(2) × 10?3 GPa?1, β b = 3.4(4) × 10?3 GPa?1, and β c = 1.7(3) × 10?3 GPa?1 (β a :β b :β c = 1:2.43:1.21). The highest compressibilities observed in this study within (100) can be ascribed to the presence of voids represented by five-membered rings of polyhedra: Al1–Al3–Al4–Al1–Al3, which allow accommodating the effect of pressure by polyhedral tilting. Polyhedral tilting around the voids also explains the higher compressibility along [010] than along [001]. The stiffer crystallographic direction observed here might be controlled by the infinite chains of edge-sharing octahedra running along [100], which act as “pillars”, making the structure less compressible along the a-axis than along the b- and c-axis. Along [100], compression can only be accommodated by deformation of the edge-sharing octahedra (and/or by compression of the Al–O bond lengths), as no polyhedral tilting can occur. In addition, a comparative elastic analysis among the mullite-type materials is carried out. 相似文献
74.
Mario Zelic Nicola Levi Alessandro Malasoma Michele Marroni Luca Pandolfi Branislav Trivic 《Geological Journal》2010,45(1):59-77
The easternmost zone of the Dinaric‐Hellenic belt is represented by the Vardar Zone, in which the Kopaonik Metamorphic Complex (KMC) is regarded as the lowermost unit. This complex is topped by the unmetamorphosed Brzece unit and is intruded by the Oligocene Kopaonik Intrusive complex. The KMC is characterized by a stratigraphy that includes metapelites and meta‐carbonates of Late Triassic age, associated with metabasites. It is characterized by a complex deformation history that comprises four phases: D1 to D4. The D1 phase structures occur only as relict structures, whereas the D2 phase structures are represented by isoclinal F2 folds, associated with a well‐developed S2 foliation. The estimated P‐T conditions for the D1 and D2 metamorphism are consistent with the upper greenschist facies. The D3 phase is characterized by west‐verging thrusts associated with upright folds. In contrast, the D4 phase is characterized by open folds (F4) associated with low‐angle normal faults. The D1 and D2 deformation phases developed during the shortening related to continental collision, whereas the subsequent D3 and D4 phases can be related to the progressive exhumation of the KMC. The D4 phase probably developed during extensional tectonics during and after emplacement of the Kopaonik Intrusive Complex. The data show that the continental units belonging to the Vardar zone had a long‐lived deformation history that was more complex that previously thought. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
75.
In order to define adequate prevention measures and to manage landslide emergencies, real-time monitoring is required. This
paper presents two different applications of the remote sensing technique: the ground-based synthetic aperture radar interferometry,
here proposed as a monitoring and early warning support for slope instability. Data acquisitions carried out through a ground-based
synthetic aperture radar interferometer, operating in Ku band, installed in front of the observed slopes, are discussed. Two case studies, based on the use of the same apparatus
(formerly developed by the Joint Research Center of the European Commission and by Ellegi-LiSALab srl), are reported: the
first one concerns the monitoring of a large landslide, named Ruinon (Valfurva, Italy). The second one deals with the monitoring
of the NW unstable slope in the Stromboli island aimed to implementing an early warning system. Acquired interferometric data
are processed to provide displacements and velocity maps of the monitored area. The monitoring services ongoing on the Ruinon
landslide and on Stromboli demonstrate the capability of this technique to operate in different operative settings (i.e.,
different phenomena and geological framework) and for different aims (monitoring for prevention, early warning, and emergency
assessment). This methodology has also been proved by national and regional authorities of civil protection in order to provide
a real-time monitoring for emergency management. 相似文献
76.
ABSTRACTReliable simulations of hydrological models require that model parameters are precisely identified. In constraining model parameters to small ranges, high parameter identifiability is achieved. In this study, it is investigated how precisely model parameters can be constrained in relation to a set of contrasting performance criteria. For this, model simulations with identical parameter samplings are carried out with a hydrological model (SWAT) applied to three contrasting catchments in Germany (lowland, mid-range mountains, alpine regions). Ten performance criteria including statistical metrics and signature measures are calculated for each model simulation. Based on the parameter identifiability that is computed separately for each performance criterion, model parameters are constrained to smaller ranges individually for each catchment. An iterative repetition of model simulations with successively constrained parameter ranges leads to more precise parameter identifiability and improves model performance. Based on these results, a more consistent handling of model parameters is achieved for model calibration. 相似文献
77.
Nicola Senesi 《Geochimica et cosmochimica acta》1981,45(2):269-272
On the basis of a lack of Mössbauer evidence and of a vague interpretation of some i.r. absorptions, Dicksonet al. (1979) conclude that no iron directly bound to humic materials persists after the usually accepted extraction and separation procedures. Many statements in the paper by Dicksonet al. (1979) appear to be contradictory with this conclusion.In this comment the author has tried to demonstrate that Mössbauer spectroscopy alone cannot give an answer to the problem, but needs further spectroscopic and chemical evidence. Mössbauer data, overinterpreted by Dicksonet al. (1979). have been critically discussed, in comparison with similar data previously obtained by various authors. Large spectroscopic—mainly Mössbauer, ESR and i.r.—evidence have been given in order to demonstrate the already well ascertained existence of organically bound iron in natural and synthetic complexes with humic substances. 相似文献
78.
A method for optimum modelling of the earth's topography, corresponding to differing meteorological phenomena, is presented.The optimum averaging scale for mountains in terms of orographic cyclo- and anti-cyclogenesis is shown to be of the order of 150 km. The use of larger or smaller averaging scales decreases the correlation between the degree of cyclo- and anti-cyclogenesis and the parameters which describe the orography.A quantitative relation between orographic cyclo- and anti-cyclogenesis and the form of orography determined by the Laplacian 2
Z
0 of the terrain function Z
0 = Z
0(x, y) is presented. 相似文献
79.
80.
Smith NA 《Marine pollution bulletin》2004,49(11-12):1105-1108
The grounding of the container feeder vessel MV CITA on Newfoundland Rocks, Isles of Scilly, had an effect on the surrounding biota and benthic environment. Included in the CITA's cargo were five 40 ft containers holding pallets of polyester film used in the production of audio and visual recording tapes. The wreckage presented a minor but potentially chronic source of pollution through the delayed release of polythene film, which was left on the seabed as it was considered insufficiently valuable to warrant salvage. The polythene disintegrated and was washed upon the foreshore of Porth Hellick in minute shreds. The adjacent foreshore and two control sites within the islands were analysed using a 5-strand line and vegetation survey with 10 random quadrats within each line to determine the environmental impact of the polythene. 相似文献