An assessment of the climate change impacts on groundwater recharge at a continental scale using a probabilistic approach with an ensemble of GCMs   总被引：1，自引：0，他引：1  

Russell S. Crosbie  Trevor Pickett  Freddie S. Mpelasoka  Geoff Hodgson  Stephen P. Charles  Olga V. Barron 《Climatic change》2013,117(1-2):41-53

This study used 16 Global Climate Models and three global warming scenarios to make projections of recharge under a 2050 climate for the entire Australian continent at a 0.05° grid resolution. The results from these 48 future climate variants have been fitted to a probability distribution to enable the results to be summarised and uncertainty quantified. The median results project a reduction in recharge across the west, centre and south of Australia and an increase in recharge across the north and a small area in the east of the continent. The range of results is quite large and for large parts of the continent encompasses both increases and decreases in recharge. This makes it difficult to utilise for water resources management so the results have been analysed with a risk analysis framework; this enables the future projections for groundwater recharge to be communicated to water managers in terms of likelihood and consequence of a reduction in recharge. This highlights an important message for water resource managers that in most areas of Australia they will be making decisions on water allocations under considerable uncertainty as to the direction and magnitude of recharge change under a future climate and that this uncertainty may be irreducible.  相似文献   

Making decisions to conserve species under climate change     

Luke P. Shoo  Ary A. Hoffmann  Stephen Garnett  Robert L. Pressey  Yvette M. Williams  Martin Taylor  Lorena Falconi  Colin J. Yates  John K. Scott  Diogo Alagador  Stephen E. Williams 《Climatic change》2013,119(2):239-246

Severe impacts on biodiversity are predicted to arise from climate change. These impacts may not be adequately addressed by conventional approaches to conservation. As a result, additional management actions are now being considered. However, there is currently limited guidance to help decision makers choose which set of actions (and in what order) is most appropriate for species that are considered to be vulnerable. Here, we provide a decision framework for the full complement of actions aimed at conserving species under climate change from ongoing conservation in existing refugia through various forms of mobility enhancement to ex situ conservation outside the natural environment. We explicitly recognize that allocation of conservation resources toward particular actions may be governed by factors such as the likelihood of success, cost and likely co-benefits to non-target species in addition to perceived vulnerability of individual species. As such, we use expert judgment of probable tradeoffs in resource allocation to inform the sequential evaluation of proposed management interventions.  相似文献   

SOUSA: the Swift Optical/Ultraviolet Supernova Archive     

Peter J. Brown  Alice A. Breeveld  Stephen Holland  Paul Kuin  Tyler Pritchard 《Astrophysics and Space Science》2014,353(1):89-96

This paper studies the motion of an infinitesimal mass in the framework of Robe’s circular restricted three-body problem in two cases; the first case is when the hydrostatic equilibrium figure of the first primary is an oblate spheroid, the shape of the second primary is considered as an oblate spheroid with oblateness coefficients up to the second zonal harmonic, while the first primary is a Roche ellipsoid in the second case and the full buoyancy of the fluid is taken into account. In case one; it is observed that there are two axial libration points on the line joining the centres of the primaries, points on the circle within the first primary are also libration points under certain conditions. It is further found that the first axial point is stable, while the second one is conditionally stable, and the circular points are unstable. It is found in case two that there is exist only one libration point (0,0,0) this point is stable.  相似文献   

A dearth of planetary transits in the direction of NGC 6940     

Ben Hood  rew Collier Cameron  Stephen R. Kane  D. M. Bramich  Keith Horne  Rachel A. Street  I. A. Bond  A. J. Penny  Y. Tsapras  A. Quirrenbach  N. Safizadeh  D. Mitchell  J. Cooke 《Monthly notices of the Royal Astronomical Society》2005,360(2):791-800

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Cipher, A Polarimeter Telescope Concept for Hard X-Ray Astronomy     

R. M. Curado Da Silva  E. Caroli  J.B. Stephen  P. Siffert 《Experimental Astronomy》2003,15(1):45-65

The polarisation of astrophysical source emission in the energy range from a few tens of keV up to the MeV region is an almost unexplored field of high-energy astrophysics. Till date, polarimetry in astrophysics–in the energy domain from hard X-rays up to soft γ-rays–has not been pursued due to the difficulties involved in obtaining sufficient sensitivity. Indeed for those few instruments that are capable of performing this type of measurement (e.g. the COMPTEL instrument on the Compton Gamma-ray Observatory and the IBIS instrument on INTEGRAL), polarimetry itself plays a secondary role in the mission objectives, as the efficiencies (0.5% and 10% maximum, respectively) and polarimetric Q factors (0.1 and 0.3, respectively) are relatively limited. In order to perform efficient polarimetric measurements for hard X-ray and soft gamma-ray sources, with an instrument of relatively robust and simple design, a CdTe based telescope (CIPHER: Coded Imager and Polarimeter for High Energy Radiation) is under study. This instrument is based on a thick (10 mm) CdTe position-sensitive spectrometer comprising four modules of 32 × 32 individual pixels, each with a surface area of 2 × 2 mm² (about 160 cm² total detection area). The polarimetric performance and design optimisation of the CIPHER detection surface have been studied by use of a Monte Carlo code. This detector, due to its intrinsic geometry, can allow efficient polarimetric measurements to be made between 100 keV and 1 MeV. In order to predict the polarimetric performance and to optimise the design and concept of the CIPHER detection plane, a Monte Carlo code based on GEANT4 library modules was developed to simulate the detector behaviour under a polarised photon flux. The Compton double event efficiency, as well bi-dimensional double event distribution maps and the corresponding polarimetric modulation factor will be presented and discussed. Modulation Q factors better than 0.50 and double event total efficiencies greater than 10% were calculated in the energy range between 100 keV and 1 MeV. Herein we will present and discuss the general problems that affect polarimetric measurements in space, such as the inclination of the source with respect to the telescope optical axis and background radiation. Q factor calculations for several beam inclinations as well as for background together with simulated astronomical sources will be presented and discussed.  相似文献   

A microearthquake study in the Gulf of Patras region, western Greece, and its seismotectonic interpretation   总被引：2，自引：0，他引：2  

N. S. Melis  M. Brooks  R. G. Pearce 《Geophysical Journal International》1989,98(3):515-524

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Biting back at Hook Head     

Stephen Moreton 《Geology Today》2000,16(5):178-179

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Thallium in meteorites     

X. Guo  R. R. Brooks  R. D. Reeves 《Meteoritics & planetary science》1994,29(1):85-88

Abstract— Thallium has been quantified in 50 iron meteorites and 6 chondrites using a combination of solvent extraction and graphite furnace atomic absorption spectrometry. The accuracy of the data was checked by analysis of two iron meteorites by laser-excited ICP mass spectrometry. The Tl abundance values for irons appear to be the first recorded and show that the Tl content allows for taxonomic separation of several groups on Tl vs. Ni abundance plots. The Tl content of irons is inversely correlated with abundances of platinum group metals such as Ir, Pt, and Rh and, in this respect, behaves like Pd and As that favour sulphur-rich phases in meteorites. Analysis of carbonaceous chondrites showed a 30-fold enrichment of Tl compared with ordinary chondrites.  相似文献   

Overlapping spreading centres: 3-D inversion of the magnetic field at 9°03'N on the East Pacific Rise     

Jean-Christophe Sempere  Ken C. Macdonald  Stephen P. Miller 《Geophysical Journal International》1984,79(3):799-811

Summary. Overlapping spreading centres (OSCs) represent a new type of plate boundary interaction in which en échelon rise segments overlap significantly and are not joined by a transform fault.
A three-dimensional Fourier inversion of the magnetic field was performed on an overlapping spreading centre to remove the effects of topography and ridge orientation. A magnetic high exists at the tip of one of the two ridge segments. Forward modelling suggests that the anomalous magnetic field cannot be attributed to the effects of topography alone. The inversion reveals the existence of a magnetization high at the tip of the eastern spreading centre. Maximum magnetization values are consistent with ones obtained in other high amplitude zones in the Pacific as well as with the measured magnetization of samples dredged in the same areas. We suggest that the magnetization high over the eastern ridge tip of the 9°03'N OSC is associated with highly evolved basalts enriched in iron and titanium. Such enrichment may be caused by enhanced crystal fractionation within an axial magma chamber which is intermittent and occasionally freezes as the eastern spreading axis propagates into older lithosphere.  相似文献   

The Iguaraçu H5 chondrite: a fall from Paraná State,Brazil     

R. R. Brooks  M. Hoashi  E. Fernandes de Lima  M. L. dos Santos  D. E. Ryan  J. Holzbecher  J. H. Johnston  Y. Kawachi  P. P. Sipiera 《Meteoritics & planetary science》1990,25(3):231-232

Abstract— The Iguaraçu meteorite, a single stone of 1200 g, fell in Paraná State, Brazil in October 1977. It is classified as an H5 ordinary chondrite with olivine of composition Fa 18.7.  相似文献