Why the South Pacific Convergence Zone is diagonal   总被引：1，自引：0，他引：1  

Karin van der Wiel  Adrian J. Matthews  Manoj M. Joshi  David P. Stevens 《Climate Dynamics》2016,46(5-6):1683-1698

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Propagation of the Madden–Julian Oscillation and scale interaction with the diurnal cycle in a high-resolution GCM     

Simon C. Peatman  Adrian J. Matthews  David P. Stevens 《Climate Dynamics》2015,45(9-10):2901-2918

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Foreword     

David Stevens 《International Journal of Applied Earth Observation and Geoinformation》2010

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Eustatic control of late Quaternary sea-level change in the Arabian/Persian Gulf     

Thomas Stevens  Matthew J. Jestico  Graham Evans  Anthony Kirkham 《Quaternary Research》2014

Accurate sea-level reconstruction is critical in understanding the drivers of coastal evolution. Inliers of shallow marine limestone and aeolianite are exposed as zeugen (carbonate-capped erosional remnants) on the southern coast of the Arabian/Persian Gulf. These have generally been accepted as evidence of a eustatically driven, last-interglacial relative sea-level highstand preceded by a penultimate glacial-age lowstand. Instead, recent optically stimulated luminescence (OSL) dating suggests a last glacial age for these deposits, requiring > 100 m of uplift since the last glacial maximum in order to keep pace with eustatic sea-level rise and implying the need for a wholesale revision of tectonic, stratigraphic and sea-level histories of the Gulf. These two hypotheses have radically different implications for regional neotectonics and land–sea distribution histories. Here we test these hypotheses using OSL dating of the zeugen formations. These new ages are remarkably consistent with earlier interpretations of the formations being last interglacial or older in age, showing that tectonic movements are negligible and eustatic sea-level variations are responsible for local sea-level changes in the Gulf. The cause of the large age differences between recent studies is unclear, although it appears related to large differences in the measured accumulated dose in different OSL samples.  相似文献   

Effects of the 2004 hurricanes on the fish assemblages in two proximate southwest Florida estuaries: Change in the context of interannual variability     

Marin?F.?D.?GreenwoodEmail author  Philip?W.?Stevens  Richard?E.?Matheson 《Estuaries and Coasts》2006,29(6):985-996

We examined interannual differences in fish assemblage structure in Tampa Bay and Charlotte Harbor, Florida, from 1996 to 2005 to reveal the extent of hurricane-induced changes in relation to multiannual variability for five different assemblages in each estuary: small-bodied fishes (<generally 80-mm standard length) along river shorelines, in river channels, along bay shorelines, and on the bay shelf (<1.5-m water depth); and large-bodied fishes (>generally 100-mm standard length) along bay shorelines. Fish assemblages tended to differ, between estuaries, as did interannual variability in assemblage structure. In the lower portions of tributary rivers to Tampa Bay, the small-bodied shoreline fish assemblage during August 2004 to July 2005, i.e., during and after the multiple hurricanes, was different from assemblages of August to July in previous years. This may have been a result of physical displacement of fish or suboptimal salinities caused by increased freshwater inflow. The small-bodied shoreline fish assemblage in Charlotte Harbor also differed between prehurricane and hurricane periods, possibly because damage to vegetated shorelines affected fish survival through a decrease in feeding and refuge habitats. In the remaining habitats, fish assemblage structure from August 2004 to July 2005 were within the range of variability exhibited over the 9-yr study period. There were several unusual fish assemblages that appeared to be attributable to drought conditions (1996, 1999–2000), suggesting that other major environmental perturbations may be as important as hurricanes in influencing assemblage structure. We conclude that although the 2004 hurricane season affected some of the fish assemblages of Tampa Bay and charlotte Harbor, these assemblages generally appeared quite resilient to natural environmental perturbations from a decadal perspective.  相似文献   

The cool wake around 4C 34.16 as seen by XMM–Newton     

I. Sakelliou  D. M. Acreman  M. J. Hardcastle  M. R. Merrifield  T. J. Ponman  I. R. Stevens 《Monthly notices of the Royal Astronomical Society》2005,360(3):1069-1076

We present XMM–Newton observations of the wake–radio galaxy system 4C 34.16, which shows a cool and dense wake trailing behind the host galaxy of 4C 34.16. A comparison with numerical simulations is enlightening, as they demonstrate that the wake is produced mainly by ram pressure stripping during the galactic motion through the surrounding cluster. The mass of the wake is a substantial fraction of the mass of the X-ray halo of an elliptical galaxy. This observational fact supports a wake formation scenario similar to that recently demonstrated numerically by Acreman et al.: the host galaxy of 4C 34.16 has fallen into its cluster, and is currently crossing its central regions. A substantial fraction of its X-ray halo has been stripped by ram pressure, and remains behind to form the galaxy wake.  相似文献   

A 1200-μm MAMBO survey of ELAIS N2 and the Lockman Hole – I. Maps, sources and number counts     

T. R. Greve  R. J. Ivison  F. Bertoldi  J. A. Stevens  J. S. Dunlop  D. Lutz  C. L. Carilli 《Monthly notices of the Royal Astronomical Society》2004,354(3):779-797

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Rest-frame optical and far-infrared observations of extremely bright Lyman-break galaxy candidates at z∼ 2.5     

R. J. Ivison  Ian Smail  Misty Bentz  J. A. Stevens  K. Menéndez-Delmestre  S. C. Chapman  A. W. Blain 《Monthly notices of the Royal Astronomical Society》2005,362(2):535-541

We have investigated the rest-frame optical and far-infrared properties of a sample of extremely bright candidate Lyman-break galaxies (LBGs) identified in the Sloan Digital Sky Survey. Their high ultraviolet luminosities and lack of strong ultraviolet emission lines are suggestive of massive starbursts, although it is possible that they are more typical luminosity LBGs which have been highly magnified by strong gravitational lensing. Alternatively, they may be an unusual class of weak-lined quasars. If the ultraviolet and submillimetre (submm) properties of these objects mirror those of less luminous, starburst LBGs, then they should have detectable rest-frame far-infrared emission. However, our submm photometry fails to detect such emission, indicating that these systems are not merely scaled-up (either intrinsically or as a result of lensing) examples of typical LBGs. In addition we have searched for the morphological signatures of strong lensing, using high-resolution, near-infrared imaging, but we find none. Instead, near-infrared spectroscopy reveals that these systems are, in fact, a rare class of broad absorption line quasars.  相似文献   

Importance of oceanic resolution and mean state on the extra-tropical response to El Niño in a matrix of coupled models     

Andrew Dawson  Adrian J. Matthews  David P. Stevens  Malcolm J. Roberts  Pier Luigi Vidale 《Climate Dynamics》2013,41(5-6):1439-1452

The extra-tropical response to El Niño in configurations of a coupled model with increased horizontal resolution in the oceanic component is shown to be more realistic than in configurations with a low resolution oceanic component. This general conclusion is independent of the atmospheric resolution. Resolving small-scale processes in the ocean produces a more realistic oceanic mean state, with a reduced cold tongue bias, which in turn allows the atmospheric model component to be forced more realistically. A realistic atmospheric basic state is critical in order to represent Rossby wave propagation in response to El Niño, and hence the extra-tropical response to El Niño. Through the use of high and low resolution configurations of the forced atmospheric-only model component we show that, in isolation, atmospheric resolution does not significantly affect the simulation of the extra-tropical response to El Niño. It is demonstrated, through perturbations to the SST forcing of the atmospheric model component, that biases in the climatological SST field typical of coupled model configurations with low oceanic resolution can account for the erroneous atmospheric basic state seen in these coupled model configurations. These results highlight the importance of resolving small-scale oceanic processes in producing a realistic large-scale mean climate in coupled models, and suggest that it might may be possible to “squeeze out” valuable extra performance from coupled models through increases to oceanic resolution alone.  相似文献   

EU 20-20-20 energy policy as a model for global climate mitigation     

Katherine Calvin  Bjorn Bakken  Marshall Wise  Sonny Kim  Patrick Luckow 《Climate Policy》2013,13(5):581-598

The EU has established an aggressive portfolio with explicit near-term targets for 2020 – to reduce GHG emissions by 20%, rising to 30% if the conditions are right, to increase the share of renewable energy to 20%, and to make a 20% improvement in energy efficiency – intended to be the first step in a long-term strategy to limit climate forcing. The effectiveness and cost of extending these measures in time are considered along with the ambition and propagation to the rest of the world. Numerical results are reported and analysed for the contribution of the portfolio's various elements through a set of sensitivity experiments. It is found that the hypothetical programme leads to very substantial reductions in GHG emissions, dramatic increases in use of electricity, and substantial changes in land-use including reduced deforestation, but at the expense of higher food prices. The GHG emissions reductions are driven primarily by the direct limits. Although the carbon price is lower under the hypothetical protocol than it would be under the emissions cap alone, the economic cost of the portfolio is higher, between 13% and 22%.  相似文献