Global assessments of the NCEP Ensemble Forecast System using altimeter data     

Campos  Ricardo Martins  Alves  Jose-Henrique G.M.  Penny  Stephen G.  Krasnopolsky  Vladimir 《Ocean Dynamics》2020,70(3):405-419

Ocean Dynamics - Forecasts of 10-m wind (U10) and significant wave height (Hs) from the National Centers for Environmental Prediction (NCEP) Ensemble Forecast System are evaluated using altimeter...  相似文献   

Vince Mannings,A. P. Boss,and S. S. Russell: Protostars and Planet,IV, Space Science Series     

Penny  Alan 《Earth, Moon, and Planets》1999,84(3):177-177

Earth, Moon, and Planets -  相似文献   

Block coals from Indiana: inferences on changing depositional environment     

Maria Mastalerz  Penny L. Padgett  Cortland F. Eble 《International Journal of Coal Geology》2000,43(1-4)

Significant differences in coal petrography, palynology and coal quality were found between the Lower Block and Upper Block Coal Members (Brazil Formation, Pennsylvanian) in Daviess County, Indiana. The Lower Block Coal Member ranges in thickness from 51 to 74 cm and the Upper Block Coal Member ranges from 20 to 65 cm. Average sulfur content and ash yield of the Lower Block coal (0.98%, 7.65%) are lower than in the Upper Block coal. Megascopically, the coals show distinct differences. The Lower Block is a banded coal with numerous thin fusain horizons and a thin clay parting in the lower third of the seam. The Upper Block coal has a dulling-upward trend, with a bright clarain found at the base that grades into a clarain and then into a durain in the upper portion of the seam. Vitrinite content of the Lower Block coal ranges from 63% to 78%, with the highest vitrinite content found in the middle portion of the seam. In the Upper Block coal, vitrinite content ranges from 40% to 83%, with the highest values found in the lower part of the seam. Ash yield is higher in the upper part of the Upper Block coal, reaching up to 40%. The Lower Block coal is dominated by lycopod trees and tree ferns. The Upper Block coal shows marked differences in spore assemblages between lower and upper parts of the seam. The lower half is dominated by large lycopod trees and tree ferns, similar to the Lower Block coal. The upper half is dominated by small lycopods, mainly Densosporites and Radiizonates. These differences between the Lower Block and Upper Block Coal Members are significant correlation tools applicable to mining exploration and chronostratigraphy.  相似文献   

Extrasolar planets around HD 196050, HD 216437 and HD 160691     

Hugh R. A. Jones  R. Paul Butler  Geoffrey W. Marcy  Chris G. Tinney  Alan J. Penny  Chris McCarthy  Brad D. Carter 《Monthly notices of the Royal Astronomical Society》2002,337(4):1170-1178

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Ocean zoning in the Northwest Atlantic     

Penny A. Doherty  Mark Butler 《Marine Policy》2006

A workshop held in Halifax, Nova Scotia, Canada, brought together marine policy makers, resource users and experts to discuss spatial planning in the marine environment. Participants explored concepts of ocean zoning and learned from other jurisdictions and related integrated management initiatives. An ocean user perspectives panel featured plenary addresses on the significance of ocean zoning to various sectors. Discussions at the workshop emphasized the need for involving all key players and clearly defining terms used in the spatial planning process.  相似文献   

Dynamic modeling suggests terrace zone asymmetry in the Chicxulub crater is caused by target heterogeneity     

Gareth S. Collins  Joanna Morgan  Penny Barton  Gail L. Christeson  Sean Gulick  Jaime Urrutia  Michael Warner  Kai Wünnemann 《Earth and Planetary Science Letters》2008,270(3-4):221-230

We investigate the cause of terrace zone asymmetry in the Chicxulub impact crater using dynamic models of crater formation. Marine seismic data acquired across the crater show that the geometry of the crater's terrace zone, a series of sedimentary megablocks that slumped into the crater from the crater rim, varies significantly around the offshore half of the crater. The seismic data also reveal that, at the time of impact, both the water depth and sediment thickness varied with azimuth around the impact site. To test whether the observed heterogeneity in the pre-impact target might have affected terrace zone geometry we constructed two end-member models of upper-target structure at Chicxulub, based on the seismic data at different azimuths. One model, representing the northwest sector, had no water layer and a 3-km thick sediment layer; the other model, representing the northeast sector, had a 2-km water layer above a 4-km sediment layer. Numerical models of vertical impacts into these two targets produced final craters that differ substantially in terrace zone geometry, suggesting that the initial water depth and sediment thickness variations affected the structure of the terrace zone at Chicxulub. Moreover, the differences in terrace zone geometry between the two numerical models are consistent with the observed differences in the geometry of the terrace zone at different azimuths around the Chicxulub crater. We conclude that asymmetry in the pre-impact target rocks at Chicxulub is likely to be the primary cause of asymmetry in the terrace zone.  相似文献   

Landforms and landscape evolution in the Skardu,Shigar and Braldu Valleys,Central Karakoram     

Yeong Bae Seong  Michael P. Bishop  Andrew Bush  Penny Clendon  Luke Copland  Robert C. Finkel  Ulrich Kamp  Lewis A. Owen  John F. Shroder 《Geomorphology》2009,103(2):251-267

The Central Karakoram, which includes K2 in Pakistan, is one of the most rapidly rising areas on Earth and exhibits complex topography and extreme relief. Impressive valley fills and glacial landforms are present throughout the valleys. The dynamics of landscape evolution of the region are currently not well understood. Consequently, the landforms were mapped and assessed in the Skardu, Shigar, and Braldu valleys, to elucidate the spatio-temporal scale dependencies of surface processes active in the region. These valleys were examined using geomorphic field methods, remote sensing, geomorphometry, and terrestrial cosmogenic nuclides (TCNs) surface exposure dating. The glaciers in this region have oscillated considerably throughout the Late Quaternary, and four glacial stages have been recognized including at least six glacial advances. Surface processes readjusted after glacier retreat, and ubiquitous mass movements and catastrophic landsliding transported material from steep slopes to valley bottoms, while glaciofluvial meltwater and glacier outburst floods redistributed sediment down valley. Glacier geochronology and late Holocene ages of the outburst flood deposits indicate that landscape evolution has been dominated by glaciation and paraglaciation during the late Quaternary.  相似文献   

A Search for CO J = 2 → 1 Emission from the Metal Rich Globular Cluster NGC 6356     

M. E. L. Hopwood  A. Evans  S. P. S. Eyres  A. Penny 《Astrophysics and Space Science》1997,251(1-2):385-388

We have observed the metal-rich globular cluster NGC 6356 in the CO J = 2 → 1 transition. The data revealed no apparent emission corresponding to the radial velocity of the cluster and we present an upper limit to the mass of gas in the cluster core. This revised version was published online in September 2006 with corrections to the Cover Date.  相似文献   

Stardust interstellar dust calibration: Hydrocode modeling of impacts on Al‐1100 foil at velocities up to 300 km s−1 and validation with experimental data     

Mark C. PRICE  Anton T. KEARSLEY  Mark J. BURCHELL  Lauren E. HOWARD  Jon K. HILLIER  Natalie A. STARKEY  Penny J. WOZNIAKIEWICZ  Mike J. COLE 《Meteoritics & planetary science》2012,47(4):684-695

Abstract– We present initial results from hydrocode modeling of impacts on Al‐1100 foils, undertaken to aid the interstellar preliminary examination (ISPE) phase for the NASA Stardust mission interstellar dust collector tray. We used Ansys’ AUTODYN to model impacts of micrometer‐scale, and smaller projectiles onto Stardust foil (100 μm thick Al‐1100) at velocities up to 300 km s^?1. It is thought that impacts onto the interstellar dust collector foils may have been made by a combination of interstellar dust particles (ISP), interplanetary dust particles (IDP) on comet, and asteroid derived orbits, β micrometeoroids, nanometer dust in the solar wind, and spacecraft derived secondary ejecta. The characteristic velocity of the potential impactors thus ranges from <<1 to a few km s^?1 (secondary ejecta), approximately 4–25 km s^?1 for ISP and IDP, up to hundreds of km s^?1 for the nanoscale dust reported by Meyer‐Vernet et al. (2009) . There are currently no extensive experimental calibrations for the higher velocity conditions, and the main focus of this work was therefore to use hydrocode models to investigate the morphometry of impact craters, as a means to determine an approximate impactor speed, and thus origin. The model was validated against existing experimental data for impact speeds up to approximately 30 km s^?1 for particles ranging in density from 2.4 kg m^?3 (glass) to 7.8 kg m^?3 (iron). Interpolation equations are given to predict the crater depth and diameter for a solid impactor with any diameter between 100 nm and 4 μm and density between 2.4 and 7.8 kg m^?3.  相似文献   

A 3.5 ka record of paleoenvironments and human occupation at Angkor Borei,Mekong Delta,southern Cambodia     

Paul Bishop  Dan Penny  Miriam Stark  Marian Scott 《Geoarchaeology》2003,18(3):359-393

Microfossil and sedimentological data from a 3.1 m core extracted from a reservoir (baray) at the ancient Cambodian settlement of Angkor Borei in the Mekong Delta have provided a continuous record of sedimentation and paleoenvironments dating from about 2000 cal yr B.C. Palynological data indicate that for much of the cal. 1st and 2nd millennia B.C. mangroves dominated the regional vegetation, while extensively and regularly burnt grasslands dominated the local vegetation. Turbid, nutrient‐rich standing water characterized the core locality, perhaps suggesting a connection with rivers in the area. An abrupt change during the cal. 5th to 6th centuries A.D. involved a dramatic reduction in grasslands and the expansion of secondary forest or re‐growth taxa. These changes are synchronous with an abrupt decline in the concentration of microscopic charcoal particles in the sediments, and the colonization of the core locality by swamp forest plants. These changes are taken to indicate a shift in land‐use strategies or, possibly, a period of land abandonment. The age for the construction of the baray is interpreted to be in the 17th–19th centuries, but this dating remains speculative. Construction of the Angkor Borei baray exploited a preexisting body of standing water, so its construction was fundamentally different from the methods used at the Angkorian capital in northern Cambodia. © 2003 Wiley Periodicals, Inc.  相似文献