Hydrothermal models of the Perth metropolitan area, Western Australia: implications for geothermal energy     

Oliver Schilling  Heather A. Sheldon  Lynn B. Reid  Soazig Corbel 《Hydrogeology Journal》2013,21(3):605-621

Hydrothermal simulations are used to provide insight into the subsurface thermal regime of the Perth metropolitan area (PMA) in Western Australia. High average permeabilities and estimated fluid flow rates in shallow aquifers of the PMA suggest that advection and convection may occur in these aquifers. These processes are simulated, using a new geological model of the PMA to constrain the geometry of aquifers, aquitards and faults. The results show that advection has a strong influence on subsurface temperature, especially in the north of the PMA, where aquifer recharge creates an area of anomalously low temperature. Convection may be important, depending on the permeability of the Yarragadee Aquifer. If convection occurs, it creates thermal highs and lows with a spacing of approximately 5 km. Some of these thermal anomalies migrate over geological time due to coupling between advection and convection, but they are stationary on human timescales. Fault permeability influences the pattern of convection. Advection and convection cause variations in the geothermal gradient which cannot be predicted by conductive models; therefore, these processes should be considered in any model that is used for assessment of geothermal resources in the PMA.  相似文献   

Next stop: the Moon     

Andrew Ball FRAS    Sarah Dunkin FRAS    David Heather 《Astronomy& Geophysics》2000,41(6):6.20-6.20

Andrew J Ball, Sarah K Dunkin and David J Heather report on optimistic and innovative ideas raised at the Fourth International Conference on Exploration and Utilisation of the Moon, which resulted in a declaration reviewing the current state of lunar exploration and setting targets for future work.  相似文献   

How U.S. ocean policy and market power can reform the coral reef wildlife trade     

Brian N. Tissot  Barbara A. Best  Eric H. Borneman  Andrew W. Bruckner  Cara H. Cooper  Heather D’Agnes  Timothy P. Fitzgerald  Amanda Leland  Susan Lieberman  Amy Mathews Amos  Rashid Sumaila  Teresa M. Telecky  Frazer McGilvray  Brian J. Plankis  Andrew L. Rhyne  Glynnis G. Roberts  Benjamin Starkhouse  Todd C. Stevenson 《Marine Policy》2010

As the world’s largest importer of marine ornamental species for the aquaria, curio, home décor, and jewelry industries, the United States has an opportunity to leverage its considerable market power to promote more sustainable trade and reduce the effects of ornamental trade stress on coral reefs worldwide. Evidence indicates that collection of some coral reef animals for these trades has caused virtual elimination of local populations, major changes in age structure, and promotion of collection practices that destroy reef habitats. Management and enforcement of collection activities in major source countries such as Indonesia and the Philippines remain weak. Strengthening US trade laws and enforcement capabilities combined with increasing consumer and industry demand for responsible conservation can create strong incentives for improving management in source countries. This is particularly important in light of the March 2010 failure of the parties to the Convention on International Trade in Endangered Species (CITES) to take action on key groups of corals.  相似文献   

Integration of optical and Synthetic Aperture Radar (SAR) imagery for delivering operational annual crop inventories     

Heather McNairn  Catherine Champagne  Jiali Shang  Delmar Holmstrom  Gordon Reichert 《ISPRS Journal of Photogrammetry and Remote Sensing》2009,64(5):434-449

Agriculture plays a critical role within Canada’s economy and, as such, sustainability of this sector is of high importance. Targeting and monitoring programs designed to promote economic and environmental sustainability are a vital component within Canada’s agricultural policy. A hierarchy of land information, including up to date information on cropping practices, is needed to measure the impacts of programs on land use decision-making and to gauge the environmental and economic benefits of these investments. A multi-year, multi-site research activity was completed to develop a robust methodology to inventory crops across Canada’s large and diverse agricultural landscapes. To move towards operational implementation the methodology must deliver accurate crop inventories, with consistency and reliability. In order to meet these operational requirements and to mitigate risk associated with reliance on a single data source, the methodology integrated both optical and Synthetic Aperture Radar (SAR) imagery. The results clearly demonstrated that multi-temporal satellite data can successfully classify crops for a variety of cropping systems present across Canada. Overall accuracies of at least 85% were achieved, and most major crops were also classified to this level of accuracy. Although multi-temporal optical data would be the preferred data source for crop classification, a SAR-optical dataset (two Envisat ASAR images and one optical image) provided acceptable accuracies and will mitigate risk associated with operational implementation. The preferred dual-polarization mode would be VV–VH. Not only were these promising classification results repeated year after year, but the target accuracies were met consistently for multiple sites across Canada, all with varying cropping systems.  相似文献   

A critical evaluation of oxidation versus reduction during metamorphism of L and LL group chondrites,and implications for asteroid spectroscopy     

Heather K. Gastineau‐Lyons  Harry Y. McSween  Michael J. Gaffey 《Meteoritics & planetary science》2002,37(1):75-89

Abstract— Modal mineralogies of individual, equilibrated (petrologic type 4–6 L and LL chondrites have been measured using an electron microprobe mapping technique, and the chemical compositions of coexisting silicate minerals have been analyzed. Progressive changes in the relative abundances and in the molar Fe/Mn and Fe/Mg ratios of olivine, low‐Ca pyroxene, and diopside occur with increasing metamorphic grade. Variations in olivine/low‐Ca pyroxene ratios (Ol/Px) and in metal abundances and compositions with petrologic type support the hypothesis that oxidation of metallic iron accompanied thermal metamorphism in ordinary chondrites. Modal Ol/Px ratios are systematically lower than normative Ol/Px ratios for the same meteorites, suggesting that the commonly used C.I.P.W. norm calculation procedure may not adequately estimate silicate mineral abundances in reduced chondrites. Ol/Px ratios calculated from visible and near‐infrared (VISNIR) reflectance spectra of the same meteorites are not in agreement with other Ol/Px determinations, possibly because of spectral complexities arising from other minerals in chondrites. Characteristic features in VISNIR spectra are sensitive to the proportions and compositions of olivine and pyroxenes, the minerals most affected by oxidative metamorphism. This work may allow spectral calibration for the determination of mineralogy and petrologic type, and thus may be useful for spectroscopic studies of asteroids.  相似文献   

Photographic monitoring of soiling and decay of roadside walls in central Oxford, England     

Mary J. Thornbush  Heather A. Viles 《Environmental Geology》2008,56(3-4):777-787

As part of the Environmental Monitoring of Integrated Transport Strategies (EMITS) project, which examined the impact of the Oxford Transport Strategy (OTS) on the soiling and decay of buildings and structures in central Oxford, England, a simple photographic survey of a sample of roadside walls was carried out in 1997, with re-surveys in 1999 and 2003. Thirty photographs were taken each time, covering an area of stonework approximately 30 × 30 cm in dimensions at 1–1.3 m above pavement level. The resulting images have been used to investigate, both qualitatively as well as quantitatively, the progression of soiling and decay. Comparison of images by eye reveals a number of minor changes in soiling and decay patterns, but generally indicates stability except at one site where dramatic, superficial damage occurred over 2 years. Quantitative analysis of decay features (concavities resulting from surface blistering, flaking, and scaling), using simple techniques in Adobe Photoshop, shows variable pixel-based size proportions of concavities across 6 years of survey. Colour images (in Lab Color) generally have a reduced proportion of pixels, representing decay features in comparison to black and white (Grayscale) images. The study conveys that colour images provide more information both for general observations of soiling and decay patterns and for segmentation of decay-produced concavities. The study indicates that simple repeat photography can reveal useful information about changing patterns of both soiling and decay, although unavoidable variation in external lighting conditions between re-surveys is a factor limiting the accuracy of change detection.  相似文献   

Confronting Power and Environmental Injustice: Legacy Pollution and the Timber Industry in Southern Mississippi     

Heather K. Sanchez  Alison E. Adams  Thomas E. Shriver 《社会与自然资源》2017,30(3):347-361

Research has documented how grass-roots activists deploy the environmental justice frame to convey their grievances and demand their right to health and safety. While scholars have highlighted the widespread success of this frame, little attention has been paid to instances where the environmental justice frame fails to resonate. Drawing from social movements and environmental justice literatures, we examine how local discursive and cultural contexts can pose barriers to environmental justice claims. Our case is based on legacy pollution from a decommissioned creosote facility in Southern Mississippi. When black residents discovered the pollution in their neighborhood, they made repeated appeals to authorities for remediation and compensation. After being denied inclusion in a lawsuit filed by white residents, they formed an environmental justice organization to mobilize support for their campaign. Findings reveal the importance of both historical contextualization and the social situation of frame deployers in analyses of the environmental justice frame.  相似文献   

Small macro‐benthic invertebrates influence the survival,growth and behaviour of juvenile green sea urchins Strongylocentrotus droebachiensis in the laboratory          下载免费PDF全文

Lindsay B. Jennings  Heather L. Hunt 《Marine Ecology》2016,37(6):1325-1335

Recent settlers of many marine benthic invertebrates are cryptic, which exposes them to a suite of animals that differs from those they may experience as adults, potentially resulting in interactions causing mortality and/or reducing growth. Previous field experiments have indicated that such is the case with small juvenile green sea urchins Strongylocentrotus droebachiensis but which taxa are responsible for the mortality and reduced growth was not determined. A laboratory study was conducted to examine the effects of small macro‐benthic invertebrates, specifically chitons, scaleworms and larger juvenile conspecifics, as well as the full suite of cobble‐dwelling organisms, on the mortality, growth and behaviour of small (<3 mm) juvenile sea urchins. The likelihood of survival of small juvenile sea urchins was lower in the presence of larger juvenile sea urchins or with the full suite of cobble‐dwelling organisms than in the absence of animals. The small juvenile sea urchins survived and grew the best when they were with chitons and scaleworms. The behaviour of small sea urchins with the full suite of cobble‐dwelling organisms was more cryptic than the behaviour of urchins with scaleworms. This study indicates that interactions with the suite of small organisms living amongst cobbles can affect survival, growth and behaviour of small juvenile sea urchins, and that larger juvenile sea urchins can be a source of mortality for smaller conspecifics.  相似文献   

FAOSTAT estimates of greenhouse gas emissions from biomass and peat fires     

Simone Rossi  Francesco N. Tubiello  Paolo Prosperi  Mirella Salvatore  Heather Jacobs  Riccardo Biancalani  Joanna I. House  Luigi Boschetti 《Climatic change》2016,135(3-4):699-711

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Erratum to: FAOSTAT estimates of greenhouse gas emissions from biomass and peat fires     

Simone Rossi  Francesco N. Tubiello  Paolo Prosperi  Mirella Salvatore  Heather Jacobs  Riccardo Biancalani  Joanna I. House  Luigi Boschetti 《Climatic change》2016,135(3-4):713-713

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