Projected changes in Malawi’s growing season     

Vizy  Edward K.  Cook  Kerry H.  Chimphamba  James  McCusker  Brent 《Climate Dynamics》2015,45(5-6):1673-1698

Climate Dynamics - Regional climate model projections at 30-km resolution are used to predict future mid-century and late-century growing season changes over Malawi due to global warming under the...  相似文献   

Statistical algorithms accounting for background density in the detection of UXO target areas at DoD munitions sites     

Brett D. Matzke  John E. Wilson  John E. Hathaway  Brent A. Pulsipher 《Stochastic Environmental Research and Risk Assessment (SERRA)》2009,23(2):181-191

Statistically defensible methods are presented for developing geophysical detector sampling plans and analyzing data for munitions response sites where unexploded ordnance (UXO) may exist. Detection methods for identifying areas of elevated anomaly density from background density are shown. Additionally, methods are described which aid in the choice of transect pattern and spacing to assure with degree of confidence that a target area (TA) of specific size, shape, and anomaly density will be identified using the detection methods. Methods for evaluating the sensitivity of designs to variation in certain parameters are also discussed. Methods presented have been incorporated into the Visual Sample Plan (VSP) software (free at ) and demonstrated at multiple sites in the United States. Application examples from actual transect designs and surveys from the previous two years are demonstrated.  相似文献   

Urban expansion in Centre County,Pennsylvania: Spatial dynamics and landscape transformations   总被引：1，自引：0，他引：1  

Nnyaladzi Batisani  Brent Yarnal 《Applied geography (Sevenoaks, England)》2009,29(2):235-249

Sprawling urban development is a major driving force of landscape fragmentation and loss of agricultural land. Despite this understanding, science has yet to realize a coherent suite of methods to analyze all circumstances of sprawl. Consequently, this paper contributes to this realization by combining three methods to address sprawl in a small US metropolitan area – Centre County, Pennsylvania: cross-tabulation to identify systematic non-random land use transitions; logistic regression to determine explanatory variables of urban land use location resulting from these transitions; and the CLUE-S regional modeling framework to project future urban land use patterns in the county. The results demonstrate the versatility of the methodology because of its ability to detect land use change despite the large proportion of the landscape that remained uncharged during the two periods under consideration, and because of its ability to distinguish systematic non-random land use transitions from random ones. The strength of the methodology is further demonstrated by its capability to allocate land use change according to change in land use location as well as to net change in land use quantity. The methodology identified soil and topography as the primary explanatory drivers of urban land use location in Centre County. Although the model is able to simulate urban land use location at the county level, it is less able to simulate these locations at the sub-county level, thereby suggesting that the explanatory variables for urban land location are not fully captured at this scale. Overall, the methodology for sprawl analyses presented in the study is robust and adds to the tools available to decision makers for assessing sprawl dynamics.  相似文献   

Tomographic analysis of reactive flow induced pore structure changes in column experiments     

Rong Cai  W. Brent Lindquist  Wooyong Um  Keith W. Jones   《Advances in water resources》2009,32(9):1396-1403

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Emplacement of the 1907 Mauna Loa basalt flow as derived from precision topography and satellite imaging     

James R. Zimbelman  W. Brent GarryAndrew K. Johnston  Steven H. Williams 《Journal of Volcanology and Geothermal Research》2008

An eruption in January of 1907, from the southwest rift zone of Mauna Loa, produced a substantial lava flow field. Satellite images and Differential Global Positioning System (DGPS) survey data, along with observations and photographs from the field, are combined to provide a new perspective on the 1907 eruption. Boundaries of the flow field from the satellite data, combined with field measurements of flow thickness, indicate an area of 25.1 km² and a volume of 86.6 million m³. The eastern lobe of the flow field covers an area of 13.1 km², with a volume of 55.0 million m³, and was emplaced with an average effusion rate of 119 m³/s (at least, for the upper portion of the lobe). Ten DGPS topographic profiles across the eastern lobe aid in distinguishing the characteristics of, and transitions between, the zones identified during the emplacement of the 1984 Mauna Loa flow. Several subdivisions have been built directly on top of or adjacent to the 1907 lava flow. The strong likelihood of future eruptions from the Mauna Loa southwest rift zone makes these housing developments of particular importance for assessments of potential volcanic hazards.  相似文献   

Modeling the ice-attenuated waves in the Great Lakes     

Bai  Peng  Wang  Jia  Chu  Philip  Hawley  Nathan  Fujisaki-Manome  Ayumi  Kessler  James  Lofgren  Brent M.  Beletsky  Dmitry  Anderson  Eric J.  Li  Yaru 《Ocean Dynamics》2020,70(7):991-1003

Ocean Dynamics - A partly coupled wave-ice model with the ability to resolve ice-induced attenuation on waves was developed using the Finite-Volume Community Ocean Model (FVCOM) framework and...  相似文献   

A Predictive Geospatial Exploration Model for Mississippi Valley Type Pb–Zn Mineralization in the Southeast Missouri Lead District     

Williams  Nathan D.  Elliott  Brent A.  Kyle  J. Richard 《Natural Resources Research》2020,29(1):285-310

The Pb–Zn sulfide concentrations hosted by dolomitized Cambrian carbonates in Southeast Missouri are world-class Mississippi Valley Type (MVT) deposits. These deposits commonly are in sites where local Precambrian basement highs resulted in depositional pinchouts of the basal Cambrian sandstones that served as a regional aquifer for basinal fluid migration driven by late Paleozoic Ouachita deformation. Mineralization also appears to be spatially related to regional faults that probably served as local fluid conduits. Understanding spatial associations between sites of known mineralization and regional geology, geochemistry, and geophysics in Southeast Missouri will be a useful guide in future exploration efforts in this region and for similar geologic settings globally. The weights-of-evidence method is used to evaluate regional geology, geochemistry, and geophysical datasets and produce favorability maps for MVT deposits in Southeast Missouri. Host rock characteristics, regional structural controls, stream sediment geochemistry, and proximity to basement highs appear to be the most useful data for predicting the location of the major deposits. This work illustrates the potential utility of mineral potential modeling to prioritize areas for exploration and identify permissive areas for undiscovered MVT mineralization.

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GIS Education and Infrastructure Challenges and Problems in Emerging Countries     

G. Brent Hall 《Transactions in GIS》1999,3(4):311-317

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Pb and Po, manganese and iron cycling across the O₂/H₂S interface of a permanently anoxic fjord: Framvaren, Norway     

Peter W. Swarzenski  Brent A. McKee  Kai Srensen  James F. Todd 《Marine Chemistry》1999,67(3-4)

Vertical profiles of dissolved and particulate ²¹⁰Po and ²¹⁰Pb were measured across the redox transition zone at Station F1 in Framvaren Fjord, Norway. In this fjord, a sharp decrease in pH above the O₂/H₂S interface facilitates the aerobic dissolution of MnO₂. In contrast, Fe(II) concentrations begin to increase only at the O₂/H₂S interface depth. Activity profiles reveal that dissolved ²¹⁰Po and ²¹⁰Pb are sequestered efficiently by particulates in surface waters. As polonium-210 and lead-210 activities descend down into the aerobic manganese reduction (AMR) zone, they are remobilized during the reductive dissolution of the carrier phase oxyhydroxides. Both ²¹⁰Po and ²¹⁰Pb are highly enriched at the O₂/H₂S interface where an active community of microbes, such as anoxygenic phototrophs (e.g., Chromatium, Chlorobium sp.), thrives. The coincident peaks in ²¹⁰Po, ²¹⁰Pb and microbial biomass suggest a strong biological influence on the behavior of these radionuclides. There is a strong covariance between the vertical distribution of Mn and Pb, indicating that their redox cycling is closely coupled and is likely microbially mediated.  相似文献   

Reducing the Influence of Skin Effects on Hydraulic Conductivity Determinations in Multilevel Samplers Installed with Direct Push Methods   总被引：1，自引：0，他引：1  

Brent J. Henebry  Gary A. Robbins 《Ground water》2000,38(6):882-886

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