The influence of initial conditions and open boundary conditions on shelf circulation in a 3D ocean-shelf model of the North East Atlantic   总被引：1，自引：0，他引：1  

Sarah L. Wakelin  Jason T. Holt  Roger Proctor 《Ocean Dynamics》2009,59(1):67-81

Data from climatology (World Ocean Atlas) and two large scale operational ocean models (Forecasting Ocean Assimilation Model (FOAM), UK Met. Office and the Navy Coastal Ocean Model (NCOM), US Naval Research Laboratory) are used to give initial and open boundary conditions for a northeast Atlantic implementation of the Proudman Oceanographic Laboratory Coastal Ocean Model System (POLCOMS). We study the effects of using the different datasets on the temperature fields and the circulation. On the continental shelf, comparisons of POLCOMS output with Advanced Very High Resolution Radiometer sea surface temperature data suggest that the effect of using different ocean model initial and boundary conditions is small and that, after 15 months of model time, the impact of the different initial conditions is negligible. Stronger evidence of influence is seen in the deeper oceanic regions of the domain. Volume fluxes through sections governing flow into and out of the North Sea, through the Irish Sea and along the shelf edge show that the impact of the different boundary conditions is small on the shelf but significant elsewhere. These results are contrasted with the use of climatology to assess the value of these Global Ocean Data Assimilation Experiment ocean model products.  相似文献   

Enhancing the effectiveness of policy-relevant integrative research in rural areas     

Piran C L White  Steve Cinderby  Dave Raffaelli  Annemarieke de Bruin  Alison Holt  Meg Huby 《Area》2009,41(4):414-424

There has been much debate about the importance of policy-relevant research in geography over the last decade. There has also been an increasing recognition by policymakers of the importance of integrative (interdisciplinary and transdisciplinary) approaches to policy-relevant research. However, geographers have been more reluctant than their colleagues in other social and natural sciences to embrace integrative research collaborations. For integrative research to achieve its full potential and to encourage greater participation from the geographical research community, we need to increase our understanding of its potential value, but also some of the challenges that it poses, and how these can be overcome. In this paper, we consider the processes involved in conducting successful integrative research from the perspective of researchers involved in these projects. We base our analysis on the results of a questionnaire survey of international integrative research programmes on environmental issues in rural areas, combined with our own experiences of working in integrative research. We conclude that effective integrative research depends on the establishment of a clear conceptual framework, the use of appropriate temporal and spatial scales in the research, effective language and communication, time and commitment, and trust and respect. We also highlight the value of stakeholder involvement in integrative research to ensure the policy relevance of the work and provide a mechanism to assist with effective knowledge transfer of the results.  相似文献   

Regional scale impacts of distinct CO(2) additions in the North Sea     

Blackford JC  Jones N  Proctor R  Holt J 《Marine pollution bulletin》2008,56(8):1461-1468

A marine system model applied to the North West European shelf seas is used to simulate the consequences of distinct CO(2) additions such as those that could arise from a failure of geological sequestration schemes. The choice of leak scenario is guided by only a small number of available observations and requires several assumptions; hence the simulations reported on are engineered to be worse case scenarios. The simulations indicate that only the most extreme scenarios are capable of producing perturbations that are likely to have environmental consequences beyond the locality of a leak event. Tidally driven mixing rather than air-sea exchange is identified as the primary mechanism for dispersal of added CO(2). We show that, given the available evidence, the environmental impact of a sequestration leak is likely to be insignificant when compared to the expected impact from continued non-mitigated atmospheric CO(2) emissions and the subsequent acidification of the marine system. We also conclude that more research, including both leak simulations and assessment of ecological impacts is necessary to fully understand the impact of CO(2) additions to the marine system.  相似文献   

Propaganda and pretext     

Holt S 《Marine pollution bulletin》2006,52(4):363-366

This Viewpoint describes and analyses the history and current features of the strategy of the Government of Japan, and the associated Institute for Cetacean Research in Tokyo, to regain control of the International Whaling Commission (IWC), to legitimise renewed unsustainable commercial whaling and to dismantle conservation measures taken by the IWC over the past three decades. A key element in that strategy now is to promote and nourish the false idea that the present crisis in world fisheries is significantly caused by the consumption of valuable fish by increasing whale populations.  相似文献   

The disc-dominated host galaxy of FR-I radio source B2 0722+30     

B. H. C. Emonts  C. N. Tadhunter  R. Morganti  T. A. Oosterloo  J. Holt  E. Brogt  G. van Moorsel 《Monthly notices of the Royal Astronomical Society》2009,396(3):1522-1536

We present new observational results that conclude that the nearby radio galaxy B2 0722+30 is one of the very few known disc galaxies in the low-redshift Universe that host a classical double-lobed radio source. In this paper, we use H  i observations, deep optical imaging, stellar population synthesis modelling and emission-line diagnostics to study the host galaxy, classify the active galactic nucleus (AGN) and investigate environmental properties under which a radio-loud AGN can occur in this system. Typical for spiral galaxies, B2 0722+30 has a regularly rotating gaseous disc throughout which star formation occurs. Dust heating by the ongoing star formation is likely responsible for the high infrared luminosity of the system. The optical emission-line properties of the central region identify a Low Ionization Nuclear Emission-line Region (LINER)-type nucleus with a relatively low [O  iii ] luminosity, in particular when compared with the total power of the Fanaroff & Riley type-I radio source that is present in this system. This classifies B2 0722+30 as a classical radio galaxy rather than a typical Seyfert galaxy. The environment of B2 0722+30 is extremely H  i -rich, with several nearby interacting galaxies. We argue that a gas-rich interaction involving B2 0722+30 is a likely cause for the triggering of the radio AGN and/or the fact that the radio source managed to escape the optical boundaries of the host galaxy.  相似文献   

Habitat Use Patterns of Newly Settled Southern Flounder, <Emphasis Type="Italic">Paralichthys lethostigma</Emphasis>, in Aransas–Copano Bay,Texas     

Suraida E. Nañez-James  Gregory W. Stunz  Scott A. Holt 《Estuaries and Coasts》2009,32(2):350-359

Southern flounder Paralichthys lethostigma populations have been declining in Texas during the past 25 years. Despite their economic importance, little is known about their juvenile habitat requirements. We examined habitat use patterns of newly settled southern flounder in three zones at varying distances from the Aransas Pass inlet in Aransas–Copano Bay by measuring densities using a beam trawl in replicate estuarine habitat types in each zone. Highest abundance occurred near the inlet in vegetated sandy areas and was lowest in nonvegetated muddy bottom in regions furthest from the inlet. We also examined a 25-year fisheries data set from Texas Parks and Wildlife Department to evaluate long-term spatiotemporal recruitment patterns in Aransas–Copano Bay. These data showed generally low recruitment during the past 25 years with highest abundance near the inlets. Our results support the importance of vegetated habitat types, especially those near tidal passes, and suggest a long-term decline in recruitment densities of southern flounder.  相似文献   

Relating discrete element method parameters to rock properties using classical and micropolar elasticity theories     

Haitham Tayseer Alassi  Rune Holt 《国际地质力学数值与分析法杂志》2012,36(10):1350-1367

Micro–macro relations for discrete element method (DEM) media are derived using both classical and micropolar elasticity theories. The DEM media are classified into two main categories: dense packing, and loose packing. For both categories, relations for Young modulus (E), Poisson's ratio (ν) to represent static behaviors, and wave velocities (P‐wave and S‐wave) to represent dynamic behaviors are derived using the internal DEM parameters (k_n, k_s) and compared with values obtained from static and dynamic numerical tests. Whereas the dynamic behaviors for the two categories and the static behaviors for the dense packing match the analytical relations, the static behavior for the loose packing does not. Micropolar elasticity theory is also used to study the behaviors of the DEM media, where it is shown that if element rotation is included, DEM media behave according to linear elasticity theory. However, if element rotation is constrained, asymmetrical stresses arise in the DEM media, and a new expression is derived for the S‐wave, which allows it, under certain conditions, to travel faster than the P‐wave. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Near-infrared spectroscopy of PKS 1549−79: a protoquasar revealed?     

M. J. Bellamy  C. N. Tadhunter  R. Morganti  K. A. Wills  J. Holt  M. D. Taylor  C. A. Watson 《Monthly notices of the Royal Astronomical Society》2003,344(4):L80-L84

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A census of young stellar populations in the warm ULIRG PKS 1345+12     

J. Rodríguez Zaurín  J. Holt  C. N. Tadhunter  R. M. González Delgado 《Monthly notices of the Royal Astronomical Society》2007,375(4):1133-1145

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Laboratory Observation and Micromechanics-Based Modelling of Sandstone on Different Scales     

Liming Li  Idar Larsen  Rune M. Holt 《Rock Mechanics and Rock Engineering》2015,48(4):1407-1422

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