The Matuyama-Brunhes reversal at Tecopa basin, southeastern California, revisited again     

Edwin E. Larson  Penny E. Patterson 《Earth and Planetary Science Letters》1993,120(3-4):311-325

Numerous records of the Matuyama-Brunhes geomagnetic transition have been obtained from paleomagnetic studies. Because few of the reversal records are of acceptable reliability, however, the exact behavior of the field during the transition has remained enigmatic. To provide confirmation of one of the more reliable records, we have re-examined the transition at two sites, 150 m apart, in lake sediments of Tecopa basin, southeastern California. The two sites are geographically very close to that of Valet et al. [10], who previously obtained a record from that site indicating that the transitional field was non-dipolar and axisymmetric.

The Matuyama-Brunhes reversal is recorded differently at each of our two sites and at that of Valet et al. [10]. Zones of mixed polarities and/or intermediate directions occur at all three sites but they differ greatly in polarity character, thickness and stratigraphic position. It appears that all three sites have provided mutually contradictory records of the transition. It is unlikely, therefore, that any of the records is acceptable for establishing the nature of the transition at this locality.

Obliteration of the transition is apparently the result of acquisition of a stable, normal-polarity overprint that appears to consist of two remanence components, one acquired during post-depositional compaction and dewatering, and one during later sediment diagenesis.  相似文献   

Looking inside stars and looking for planets     

Alan Penny 《Astronomy& Geophysics》2002,43(6):6.30-6.31

Asteroseismology and extrasolar planets are the main science goals of the Eddington mission, now approved by ESA for a 2007 launch. Alan Penny presents a summary of the January 2002 RAS meeting that discussed the sciences of this wide-field high-precision photometric space telescope. Since the date of this meeting, ESA has decided to implement the mission in the framework of a 2007–08 launch.  相似文献   

The pre-main-sequence binary HK Ori: spectro-astrometry and EXPORT data     

D. Baines  R. D. Oudmaijer  A. Mora  C. Eiroa  John M. Porter  B. Merín  B. Montesinos  D. de Winter  A. Cameron  J. K. Davies  H. J. Deeg  R. Ferlet  C. A. Grady  A. W. Harris  M. G. Hoare  K. Horne  S. L. Lumsden  L. F. Miranda  A. Penny  A. Quirrenbach 《Monthly notices of the Royal Astronomical Society》2004,353(2):697-704

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Implications of CMIP3 model biases and uncertainties for climate projections in the western tropical Pacific   总被引：1，自引：0，他引：1  

Jaclyn N. Brown  Alex Sen Gupta  Josephine R. Brown  Les C. Muir  James S. Risbey  Penny Whetton  Xuebin Zhang  Alexandre Ganachaud  Brad Murphy  Susan E. Wijffels 《Climatic change》2013,119(1):147-161

Regional climate projections in the Pacific region are potentially sensitive to a range of existing model biases. This study examines the implications of coupled model biases on regional climate projections in the tropical western Pacific. Model biases appear in the simulation of the El Niño Southern Oscillation, the location and movement of the South Pacific Convergence Zone, rainfall patterns, and the mean state of the ocean–atmosphere system including the cold tongue bias and erroneous location of the edge of the Western Pacific warm pool. These biases are examined in the CMIP3 20th century climate models and used to provide some context to the uncertainty in interpretations of regional-scale climate projections for the 21st century. To demonstrate, we provide examples for two island nations that are located in different climate zones and so are affected by different biases: Nauru and Palau. We discuss some of the common approaches to analyze climate projections and whether they are effective in reducing the effect of model biases. These approaches include model selection, calculating multi model means, downscaling and bias correcting.  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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Quaternary glacial history of the Central Karakoram   总被引：3，自引：0，他引：3  

Yeong Bae Seong  Lewis A. Owen  Michael P. Bishop  Andrew Bush  Penny Clendon  Luke Copland  Robert Finkel  Ulrich Kamp  John F. Shroder Jr. 《Quaternary Science Reviews》2007,26(25-28):3384-3405

The Quaternary glacial history of the world's highest mountains, the Central Karakoram, is examined for the first time using geomorphic mapping of landforms and sediments, and ¹⁰Be terrestrial cosmogenic nuclide surface exposure dating of boulders on the moraines and glacially eroded surfaces. Four glacial stages are defined: the Bunthang glacial stage (>0.7 Ma); the Skardu glacial stage (marine Oxygen Isotope Stage [MIS] 6 or older); the Mungo glacial stage (MIS 2); and the Askole glacial stage (Holocene). Glaciers advanced several times during each glacial stage. These advances are not well defined for the oldest glacial stages, but during the Mungo and Askole glacial stages glacial advances likely occurred at 16, 11–13, 5 and 0.8 ka. The extent of glaciation in this region became increasingly more restricted over time. In the Braldu and Shigar valleys, glaciers advanced >150 km during the Bunthang and Skardu glacial stages, while glaciers advanced >80 km beyond their present positions during the Mungo glacial stage. In contrast, glaciers advanced a few kilometers from present ice margins during the Askole glacial stage. Glacier in this region likely respond in a complex fashion to the same forcing that causes changes in Northern Hemisphere oceans and ice sheets, teleconnected via the mid-latitude westerlies, and also to changes in monsoonal intensity.  相似文献   

anem: A Simple Web-Based Platform to Build Stakeholder Understanding of Groundwater Behavior     

Gopal Penny  Connor Mullen  Diogo Bolster  Bruce Huber  Marc F. Müller 《Ground water》2021,59(2):273-280

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Bridging the gap: empowering decision-making for adaptation through the UK Climate Impacts Programme     

Merylyn McKenzie Hedger  Richenda Connell  Penny Bramwell 《Climate Policy》2013,13(2):201-215

Abstract

The methods, tools and outputs of the UK Climate Impacts Programme (UKCIP) show how building adaptive capacity to climate change can be embedded within a wide range of organizations. UKCIP has been operating since 1997 to support decision-makers' assessments of their vulnerability to climate change so that they can plan how to adapt. Whilst stakeholder engagement is now generally regarded as vital to ensure that research meets the needs of decision-makers for information, this usually means that stakeholders are positioned in a ‘consultative’ role in research. In contrast, the UKCIP aims to bridge the gap between research and policy so that decision-makers take control to produce research in ways that are useful to them. The Programme has been flexible and was developed incrementally, with increased scientific understanding, taking advantage of collaborative funding and facilitating long-standing partnerships. Whilst the core framework of scenarios and tools has been developed centrally, most studies have been stakeholder-funded and led. The Programme's results suggest that if decision-makers are supported, capacity is built for assessments, and crucially, research outputs are directly applicable to their ongoing work and strategic planning. This capacity-building has worked across scales and sectors and is an effective route to mainstreaming climate change adaptation. The implication, therefore, is that more support should be given by funding agencies to develop institutional capacity to support adaptation to climate change in both the private and public sectors.  相似文献   

Constructing Interfaces between (and within) Geographical Information Systems     

Richard T. Pascoe  John P. Penny 《International journal of geographical information science》2013,27(3):275-291

Abstract

An interface is a software package used, alone or in conjunction with other interfaces, to transfer data from one geographical information system to another, or between different representations within a single GIS. The aim in this paper is to extend the traditional view of an interface to include interfaces that use communication networks to move data between (and within) GIS. We suggest that, to exchange data across a network, the best solution may be to construct a set of communicating interfaces, each able to send data to, and receive data from, other communicating interfaces. We describe a working set of communicating interfaces that transfer data between a number of GIS data representations.  相似文献   

Rates of fluvial bedrock incision within an actively uplifting orogen: Central Karakoram Mountains, northern Pakistan     

Yeong Bae Seong  Lewis A. Owen  Michael P. Bishop  Andrew Bush  Penny Clendon  Luke Copland  Robert C. Finkel  Ulrich Kamp  John F. Shroder Jr. 《Geomorphology》2008,97(3-4):274-286

Terrestrial cosmogenic nuclide (TCN) ¹⁰Be surface exposure ages for strath terraces along the Braldu River in the Central Karakoram Mountains range from 0.8 to 11 ka. This indicates that strath terrace formation began to occur rapidly upon deglaciation of the Braldu valley at  11 ka. Fluvial incision rates for the Braldu River based on the TCN ages for strath terraces range from 2 to 29 mm/a. The fluvial incision rates for the central gorged section of the Braldu River are an order of magnitude greater than those for the upper and lower reaches. This difference is reflected in the modern stream gradient and valley morphology. The higher incision rates in the gorged central reach of the Braldu River likely reflect differential uplift above the Main Karakoram Thrust that has resulted in the presence of a knickpoint and more rapid fluvial incision. The postglacial fluvial incision rate (2–3 mm/a) for the upper and lower reaches are of the same order of magnitude as the exhumation rates estimated from previously published thermochronological data for the Baltoro granite in the upper catchment region and for the adjacent Himalayan regions.  相似文献