Spatially constrained clustering of ecological units to facilitate the design of integrated water monitoring networks in the St. Lawrence Basin     

Matthew D. Adams  Pavlos S. Kanaroglou  Paulin Coulibaly 《International journal of geographical information science》2016,30(2):390-404

Water monitoring networks are generally classified into surface water, precipitation, groundwater or water quality monitoring networks. The design of these networks typically occurs in isolation from each other. We present a regionalization approach to identify homogeneous subregions of large basins that are suitable as areas for the optimization of an integrated water monitoring network. The study area, which comprises a portion of the St. Lawrence Basin, was spatially divided using ecological units. For each ecological unit, 21 attributes were derived including both environmental and hydrological indicators. A spatially constrained regionalization technique was applied to define the final regions. A scree plot was used to determine the number of regions. The sensitivity of the technique to the correlation in the attribute data was removed by utilizing principal component analysis to reduce correlation between attribute data. During regionalization, the component values were weighted by their proportion of the total variance explained. The four regions in the final configuration had areas from 19% to 31% of the total area, 63,597 km². For the St. Lawrence Basin, this approach is effective for defining homogeneous regions that can be used in further research on the optimization of integrated water monitoring networks. The approach is portable to other regions and can incorporate any set of attribute data that is valuable to the regionalization objective.  相似文献   

Late Pleistocene climate inferences from a water balance model of Jakes Valley,Nevada (USA)     

Cornelia Barth  Douglas P. Boyle  Benjamin J. Hatchett  Scott D. Bassett  Christopher B. Garner  Kenneth D. Adams 《Journal of Paleolimnology》2016,56(2-3):109-122

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Hydrography of the East Shetland Basin in relation to decadal North Sea variability   总被引：2，自引：0，他引：2  

Turrell  W. R.; Slesser  G.; Payne  R.; Adams  R. D.; Gillibrand  P. A. 《ICES Journal of Marine Science》1996,53(6):899-916

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Measurement of the Growth of Perturbations on Blast Waves in a Mixed Gas     

A. D. Edens  R. G. Adams  P. K. Rambo  I. C. Smith  J. L. Porter  T. Ditmire 《Astrophysics and Space Science》2007,307(1-3):127-130

We have performed a series of experiments examining the properties of high Mach number blast waves. Experiments were conducted on the Z-Beamlet laser at Sandia National Laboratories. We created blast waves in the laboratory by using ∼1000 J laser pulses to illuminate millimeter scale solid targets immersed in gas. Our experiments studied the validity of theories forwarded by Ryu and Vishniac (1987, 1991) and Vishniac (1983) to explain the dynamics of perturbations on astrophysical blast waves. These experiments consisted of a systematic scan of the decay rates of perturbations of known primary mode number induced on the surface of blast waves by means of a regularly spaced wire array. The amplitude of the induced perturbations relative to the radius of the blast wave was tracked and fit to a power law in time. Measurements were taken for a number of different mode numbers in a mixed gas consisting of 7.5 Torr xenon and 2.5 Torr nitrogen and the results are compared to theoretical predictions. It is found that two of the three mode numbers imply one polytropic index while the third case, which is the most complicated for several reasons, implies a higher polytropic index.  相似文献   

Blue stragglers as stellar collision products: the angular momentum question     

Alison Sills  Tim Adams  Melvyn B. Davies 《Monthly notices of the Royal Astronomical Society》2005,358(3):716-725

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The crustal evolution of South America from a zircon Hf‐isotope perspective          下载免费PDF全文

Carita Augustsson  Arne P. Willner  Tobias Rüsing  Hans Niemeyer  Axel Gerdes  Christopher J. Adams  Hubert Miller 《地学学报》2016,28(2):128-137

Hf‐isotope data of >1100 detrital zircon grains from the Palaeozoic, south‐central Andean Gondwana margin record the complete crustal evolution of South America, which was the predominant source. The oldest grains, with crustal residence ages of 3.8–4.0 Ga, are consistent with complete recycling of existing continental crust around 4 Ga. We confirm three major Archaean, Palaeoproterozoic (Transamazonian) and late Mesoproterozoic to early Neoproterozoic crust‐addition phases as well as six igneous phases during Proterozoic to Palaeozoic time involving mixing of juvenile and crustally reworked material. A late Mesoproterozoic to early Neoproterozoic, Grenville‐age igneous belt can be postulated along the palaeo‐margin of South America. This belt was the basement for later magmatic arcs and accreted allochthonous microcontinents as recorded by similar crustal residence ages. Crustal reworking likely dominated over juvenile addition during the Palaeozoic era, and Proterozoic and Archaean zircon was mainly crustally reworked from the eroding, thickened Ordovician Famatinian arc.  相似文献   

Preparing for real-time weather risk management: the decision models of household evacuation under uncertainty for Taiwanese and US residents     

Lyu  Ya-Pin  Adams  Terri 《Natural Hazards》2022,114(1):405-425

Natural Hazards - The frequency of extreme weather events has increased in recent decades due to climate change, and the demand for both more accurate weather forecasts and early warnings surges in...  相似文献   

Mass transfer in eccentric binaries: the new oil-on-water smoothed particle hydrodynamics technique     

Ross P. Church  Johann Dischler  Melvyn B. Davies  Christopher. A. Tout  Tim Adams  Martin E. Beer 《Monthly notices of the Royal Astronomical Society》2009,395(2):1127-1134

To measure the onset of mass transfer in eccentric binaries, we have developed a two-phase smoothed particle hydrodynamics (SPH) technique. Mass transfer is important in the evolution of close binaries, and a key issue is to determine the separation at which mass transfer begins. The circular case is well understood and can be treated through the use of the Roche formalism. To treat the eccentric case, we use a newly developed two-phase system. The body of the donor star is made up from high-mass water particles, whilst the atmosphere is modelled with low-mass oil particles. Both sets of particles take part fully in SPH interactions. To test the technique, we model circular mass-transfer binaries containing a  0.6 M_⊙  donor star and a  1 M_⊙  white dwarf; such binaries are thought to form cataclysmic variable (CV) systems. We find that we can reproduce a reasonable CV mass-transfer rate, and that our extended atmosphere gives a separation that is too large by approximately 16 per cent, although its pressure scale height is considerably exaggerated. We use the technique to measure the semimajor axis required for the onset of mass transfer in binaries with a mass ratio of   q = 0.6  and a range of eccentricities. Comparing to the value obtained by considering the instantaneous Roche lobe at pericentre, we find that the radius of the star required for mass transfer to begin decreases systematically with increasing eccentricity.  相似文献   

Visible and near-infra-red transmission and reflectance measurements of the Luna 20 soil     

John B. Adams  Peter M. Bell  James E. Conel  H.K. Mao  Thomas B. McCord  Douglas B. Nash 《Geochimica et cosmochimica acta》1973,37(4):731-743

Visible and near-infra-red spectra of chemically analyzed grains of glass and minerals from the Luna 20 sample were compared with diffuse reflectance spectra of the bulk soil. As in the spectra of soil samples from other localities on the Moon, pyroxene contributes two broad absorption features near 1 μm and 2 μm. The soil has a high integral reflectance (or albedo) arising from plagioclase, which appears to be the dominant mineral in the lunar highlands. The Luna 20 soil curve is most similar to the reflectance curves of the non-rayed soils at Apollo 16, in agreement with the generally similar mineralogy of these samples. The average pyroxene composition in the Luna 20 soil, as determined from the absorption bands in the diffuse reflectance spectra, and analyses of single crystals, is more calcic than in the lithic fragments. Thus, the soil appears to have a few per cent of admixed material derived from mare basalts. Comparison of the soil spectrum with telescopic curves of nearby areas reveals a close similarity; however, the Luna 20 sample is slightly less mature than expected. Luna 20 may have sampled subsurface material that is fresher than the regional surface soil, or alternatively, the Luna 20 area may contain an admixture of relatively recently exposed material from a ray crater.  相似文献   

Artificial watershed acidification on the Fernow Experimental Forest, USA     

M. B. Adams  P. J. Edwards  F. Wood  J. N. Kochenderfer 《Journal of Hydrology》1993,150(2-4):505-519

A whole-watershed manipulation project was begun on the Fernow Experimental Forest in West Virginia, USA, in 1987, with the objective of increasing understanding of the effects of acidic deposition on forest ecosystems. Two treatment watersheds (WS9 and WS3) and one control watershed (WS4) were included. Treatments were twice-ambient N and S deposition, applied via NH₄SO₄ fertilizer, with three applications per year. Three years of pretreatment data were collected and used for calibration. Stream water chemistry data collected during 3 years of treatment were evaluated. Stream water pH and electrical conductivity were not significantly affected by the elevated N and S inputs on either treatment watershed. On WS9, there were no statistically significant treatment effects on stream water export of Ca, SO₄, or NO₃. On WS3, however, stream export of both NO₃ and Ca have increased as a result of acidification treatments. The implications of these results are discussed. Research is continuing so that the processes involved may be elucidated. In addition, effects on vegetation, aquatic invertebrates and amphibians also are being evaluated.  相似文献