The role of hydrogeological setting in two Canadian peatlands investigated through 2D steady-state groundwater flow modelling     

Anne Quillet  Stéphanie Pellerin  Vincent Cloutier  Miryane Ferlatte  Claudio Paniconi 《水文科学杂志》2017,62(15):2541-2557

This study investigated how hydrogeological setting influences aquifer–peatland connections in slope and basin peatlands. Steady-state groundwater flow was simulated using Modflow on 2D transects for an esker slope peatland and for a basin peatland in southern Quebec (Canada). Simulations investigated how hydraulic heads and groundwater flow exported toward runoff from the peatland can be influenced by recharge, hydraulic properties, and heterogeneity. The slope peatland model was strongly dominated by horizontal flow from the esker. This suggests that slope peatlands are dependent on the hydrogeological conditions of the adjacent aquifer reservoir, but are resilient to hydrological changes. The basin peatland produced groundwater outflow to the surface aquifer. Lateral and vertical peat heterogeneity due to peat decomposition or compaction were identified as having a significant influence on fluxes. These results suggest that basin peatlands are more dependent on recharge conditions, and could be more susceptible to land use and climate changes.  相似文献   

Shipboard sunphotometer measurements of aerosol optical depth spectra and columnar water vapor during ACE‐2, and comparison with selected land, ship, aircraft, and satellite measurements     

John M. Livingston  Vladimir N. Kapustin  Beat Schmid  Philip B. Russell  Patricia K. Quinn  Timothy S. Bates  Philip A. Durkee  Peter J. Smith  Volker Freudenthaler  Matthias Wiegner  Dave S. Covert  Santiago Gassó  Dean Hegg  Donald R. Collins  Richard C. Flagan  John H. Seinfeld  Vito Vitale  Claudio Tomasi 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):594-619

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The effect of the ¹⁹F(α, p)²²Ne reaction rate uncertainty on the yield of fluorine from Wolf–Rayet stars     

Richard J. Stancliffe  Maria Lugaro  Claudio Ugalde  Christopher A. Tout  Joachim Görres  Michael Wiescher 《Monthly notices of the Royal Astronomical Society》2005,360(1):375-379

In the light of recent recalculations of the  ¹⁹F(α, p)²²Ne  reaction rate, we present results of the expected yield of ¹⁹F from Wolf–Rayet (WR) stars. In addition to using the recommended rate, we have computed models using the upper and lower limits for the rate, and hence we constrain the uncertainty in the yield with respect to this reaction. We find a yield of  3.1 × 10⁻⁴ M_⊙  of ¹⁹F with our recommended rate, and a difference of a factor of 2 between the yields computed with the upper and lower limits. In comparison with previous work we find a difference in the yield of a factor of approximately 4, connected with a different choice of mass loss. Model uncertainties must be carefully evaluated in order to obtain a reliable estimate of the yield, together with its uncertainties, of fluorine from WR stars.  相似文献   

On the MHD Acceleration of Astrophysical Jets     

Claudio Zanni  Attilio Ferrari  Silvano Massaglia  Gianluigi Bodo  Paola Rossi 《Astrophysics and Space Science》2004,293(1-2):99-106

We present a 2.5D magnetohydrodynamic (MHD) simulation of the acceleration of a collimated jet from a magnetized accretion disk. We employ a MHD Adaptive Mesh Refinement (AMR) code (FLASH—University of Chicago). Thanks to this tool we can follow the evolution of the system for many dynamical timescales with a high-spatial resolution. Assuming an initial condition in which a Keplerian disk, thus with no accretion motions, is threaded by a uniform poloidal magnetic field, we show how both the accretion flow and the acceleration of the outflow occur, and we present in detail which are the forces responsible for the jet launching and collimation. Our simulation also shows how the collimating forces due to the self-generated toroidal magnetic field can produce some peculiar knotty features.  相似文献   

Deformation of partially molten granite: a review and comparison of experimental and natural case studies   总被引：4，自引：0，他引：4  

Claudio L. Rosenberg 《International Journal of Earth Sciences》2001,90(1):60-76

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Coronal abundance of elements and a model of the quiet Sun from radio observations     

Claudio Chiuderi  Franca Chiuderi Drago  Giancarlo Noci 《Solar physics》1972,26(2):343-353

It is shown that the combined use of radio observations of the quiet Sun and UV line intensities allows to compute the absolute coronal abundance of the elements. The abundances found by this method agree very well with the most recent determinations. A model of the transition region and corona in hydrostatic equilibrium is also presented. Similarities and differences with models based on UV observations are discussed.  相似文献   

The structure of coronal magnetic loops     

Riccardo Giachetti  Gerard Van Hoven  Claudio Chiuderi 《Solar physics》1977,55(2):371-386

We present the second part of a complete theory for the plasma and field structure of a cool coronal arch, corresponding to those observed in the EUV from Skylab. The global magneto-hydrodynamic (MHD) stability of a previously described equilibrium-loop model is evaluated, and compared with that of an unmodified ambient force-free field. The influence of the photospheric boundary condition is also evaluated, producing a specification of stability limits which depend on the relative field and plasma pressures and scale widths. The resulting restrictions on the allowable field configuration of a coronal loop are then compared with observed values. The implications of this general method for deducing small-scale coronal magnetic-field structure from the measured plasma profile of an emissive feature are also described.  相似文献   

The decline of Daphnia hyalina galeata in Lago Maggiore: a comparison of the population dynamics before and after oligotrophication     

Marina Manca  Claudio Ramoni  Patrizia Comoli 《Aquatic Sciences - Research Across Boundaries》2000,62(2):142-153

We reconstruct the impact of different environmental cues on Daphnia seasonal dynamics by means of an analysis of demographic and reproductive parameters, as well as of the size structure of the population. Data from 1996, indicative of the most recent productivity of the lake, with those from 1973, when the lake was meso-eutrophic, allow a discussion of the relevance of the observed changes for the structure of the pelagic food web of Lago Maggiore. Daphnia summer dynamics is mainly controlled by Bythotrephes longimanus. This is quite a different situation from that of the past, when Leptodora kindtii was the prevalent predatory cladocera. The size structure of Daphnia population revealed a depletion of small ovigerous females with increases in the predator. Our data allow a discussion of the idea, recently proposed, of Bythotrephes longimanus as a visual sit- and -wait predator.  相似文献   

Disc galaxy evolution models in a hierarchical formation scenario: structure and dynamics     

Claudio Firmani  Vladimir Avila-Reese 《Monthly notices of the Royal Astronomical Society》2000,315(3):457-472

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Comment on Manuella et al. “The Hyblean xenolith suite (Sicily): an unexpected legacy of the Ionian–Tethys realm”     

Luigi Beccaluva  Gianluca Bianchini  Massimo Coltorti  Claudio Natali 《International Journal of Earth Sciences》2015,104(6):1679-1684

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