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151.
This paper identifies and examines current coastal issues and conflicts in the northwest Europe region through the use of questionnaire surveys. The overall management concerns and outstanding problems across the region are highlighted and the results are presented in relation to previously identified management issues in northeast England, east Grampian in Scotland, and France. The survey presents a list of identified issues, each of which has a direct relationship to one of the 3 pillars of sustainable development, (environment, economic and social), and therefore the Lisbon Agenda (economic and social) and the Gothenburg Agenda (environment and environmental risk). The survey reveals that the important coastal management issues across the region are the large-scale concerns traditionally associated with ICZM: land-use planning, estuary management, natural resource and landscape protection, and water quality. Generally, respondents considered that management response to these issues is poor. Dissatisfaction levels were particularly high in France and Ireland, and to a lesser extent, in England. Water quality management escapes general criticism. This can be regarded as a positive finding, because it indicates that pan-European initiatives (the water-related EU directives) can deal effectively with this pan-European problem. The paper considers the links between the main issues across North West Europe and aims to distinguish how current coastal management practices have affected the range of issues arising.  相似文献   
152.
We present results from a suite of forward transient numerical modelling experiments of the British and Irish Ice Sheet (BIIS), consisting of Scottish, Welsh and Irish accumulation centres, spanning the last Glacial period from 38 to 10 ka BP. The 3D thermomechanical model employed uses higher-order physics to solve longitudinal (membrane) stresses and to reproduce grounding-line dynamics. Surface mass balance is derived using a distributed degree-day calculation based on a reference climatology from mean (1961–1990) precipitation and temperature patterns. The model is perturbed from this reference state by a scaled NGRIP oxygen isotope curve and the SPECMAP sea-level reconstruction. Isostatic response to ice loading is computed using an elastic lithosphere/relaxed asthenosphere scheme. A suite of 350 simulations were designed to explore the parameter space of model uncertainties and sensitivities, to yield a subset of experiments that showed close correspondence to offshore and onshore ice-directional indicators, broad BIIS chronology, and the relative sea-level record. Three of these simulations are described in further detail and indicate that the separate ice centres of the modelled BIIS complex are dynamically interdependent during the build up to maximum conditions, but remain largely independent throughout much of the simulation. The modelled BIIS is extremely dynamic, drained mainly by a number of transient but recurrent ice streams which dynamically switch and fluctuate in extent and intensity on a centennial time-scale. A series of binge/purge, advance/retreat, cycles are identified which correspond to alternating periods of relatively cold-based ice, (associated with a high aspect ratio and net growth), and wet-based ice with a lower aspect ratio, characterised by streaming. The timing and dynamics of these events are determined through a combination of basal thermomechanical switching spatially propagated and amplified through longitudinal coupling, but are modulated and phase-lagged to the oscillations within the NGRIP record of climate forcing. Phases of predominant streaming activity coincide with periods of maximum ice extent and are triggered by abrupt transitions from a cold to relatively warm climate, resulting in major iceberg/melt discharge events into the North Sea and Atlantic Ocean. The broad chronology of the modelled BIIS indicates a maximum extent at ~20 ka, with fast-flowing ice across its western and northern sectors that extended to the continental shelf edge. Fast-flowing streams also dominate the Irish Sea and North Sea Basin sectors and impinge onto SW England and East Anglia. From ~19 ka BP deglaciation is achieved in less than 2000 years, discharging the freshwater equivalent of ~2 m global sea-level rise. A much reduced ice sheet centred on Scotland undergoes subsequent retrenchment and a series of advance/retreat cycles into the North Sea Basin from 17 ka onwards, culminating in a sustained Younger Dryas event from 13 to 11.5 ka BP. Modelled ice cover is persistent across the Western and Central Highlands until the last remnant glaciers disappear around 10.5 ka BP.  相似文献   
153.
The eastern Alaska Beaufort Sea coast is characterized by numerous shallow (2–5 m) estuarine lagoons, fed by streams and small rivers that drain northward from the Brooks Range through the arctic coastal plain, and bounded seaward by barrier islands and shoals. Millions of birds from six continents nest and forage during the summer period in this region using the river deltas, lagoons, and shoreline along with several species of anadromous and marine fish. We examined biogeochemical processes linking the benthic community to the overall food web structure of these poorly studied but pristine estuaries, which are largely covered by 1.8 m of ice for 10 months annually. In summer, these lagoons are relatively warm with brackish salinities (5–10°C, S = 10–25) compared to more open coastal waters (0–5°C, S > 27). The stable isotopic composition of organic materials in sediments (i.e., benthic particulate organic matter) and water column suspended particulate organic matter from both streams and lagoons are largely indistinguishable and reflect strong terrestrial contributions, based upon δ13C and δ15N values (−25.6‰ to −27.4‰ and 1.4‰ to 3.3‰, respectively). By comparison, shifts toward more heavy isotope-enriched organic materials reflecting marine influence are observed on the adjacent coastal shelf (−24.8‰ to −25.4‰ and 3.4‰ to 5.3‰, respectively). The isotopic composition of lagoon fauna is consistent with a food web dominated by omnivorous detritovores strongly dependent on microbial processing of terrestrial sources of carbon. Biomagnification of 15N in benthic organisms indicate that the benthic food web in lagoons support up to four trophic levels, with carnivorous gastropod predators and benthic fishes (δ15N values up to 14.4‰) at the apex.  相似文献   
154.
Jialing River, which covers a basin area of 160,000 km2 and a length of 1,280 km, is the largest tributary of the catchment area in Three Gorges Reservoir Area, China. In recent years, water quality in the reservoir area section of Jialing River has been degraded due to land use and the rural residential area induced by non-point source pollution. Therefore, the semi-distributed land-use runoff process (SLURP) hydrological model has been introduced and used to simulate the integrated hydrological cycle of the Jialing River Watershed (JRW). A coupling watershed model between the SLURP hydrological model and dissolved non-point source pollution model has been proposed in an attempt to evaluate the potential dissolved non-point source pollution load; it enhances the simulation precision of runoff and pollution load which are both based on the same division of land use types in the watershed. The proposed model has been applied in JRW to simulate the temporal and spatial distribution of the dissolved total nitrogen (DTN) and dissolved total phosphorus (DTP) pollution load for the period 1990–2007. It is shown that both the temporal and spatial distribution of DTN and DTP load are positively correlated to annual rainfall height. Land use is the key factor controlling the distribution of DTN and DTP load. The source compositions of DTN and DTP are different, where average DTN pollution load in descending order is land use 67.2%, livestock and poultry breeding 30.5%, and rural settlements 2.2%; and for DTP, livestock and poultry breeding is 50%, land use 48.8%, and rural settlements 1.2%. The contribution rates of DTN and DTP load in each sub-basin indicate the sensitivity of the results to the temporal and spatial distribution of different pollution sources. These data were of great significance for the prediction and estimation of the future changing trends of dissolved non-point source pollution load carried by rainfall runoff in the JRW and for studies of their transport and influence in the Three Gorges Reservoir.  相似文献   
155.
Lightning fatalities in Colombia from 2000 to 2009   总被引:1,自引:0,他引:1  
National lightning fatality information has been gathered and published for Australia, Canada, the USA, and Western Europe, but few such studies have taken place and been published in the formal literature during the last decade in other areas. National lightning fatality data are difficult to collect in many countries, especially in tropical regions, despite a high frequency of lightning. To partially fill this gap, the current paper provides the first comprehensive national summary of lightning deaths in Colombia. Data from the National Administrative Department of Statistics were gathered for 2000 through 2009 and were classified according to the number of fatalities by year, month, gender, age, and location of the fatality. These data were assigned to geographical departments to determine the fatality rates per type of population. Comparison was also made with the population percentage in rural areas where the outdoor lightning risk may be greater than in cities due to labor-intensive agricultural practices, housing that is unsafe from the lightning threat, lack of access to weather forecasts and lightning safety knowledge, and other factors. Data from an international lightning locating system also were used to determine the annual lightning frequency and monthly totals in Colombia. During the ten study years, 757 deaths were identified. The highest mortality rates were in rural areas with a maximum of 7.69 deaths per million per year in the Vaupes Department of eastern Colombia. The death rate for all of Colombia was 1.78 per million per year during the same period.  相似文献   
156.
We present new results of Cassini's T9 flyby with complementary observations from T18. Based on Cassini plasma spectrometer (CAPS) and Cassini magnetometer (MAG), compositional evidence shows the upstream flow for both T9 and T18 appears composed of light ions (H+ and H2+), with external pressures ∼30 times lower than that for the earlier TA flyby where heavy ions dominated the magnetospheric plasma. When describing the plasma heating and sputtering of Titan's atmosphere, T9 and T18 can be considered interactions of low magnetospheric energy input. On the other hand, T5, when heavy ion fluxes are observed to be higher than typical (i.e., TA), represents the limiting case of high magnetospheric energy input to Titan's upper atmosphere. Anisotropy estimates of the upstream flow are 1<T/T<3 and the flow is perpendicular to B, indicative of local picked up ions from Titan's H and H2 coronae extending to Titan's Hill sphere radius. Beyond this distance the corona forms a neutral torus that surrounds Saturn. The T9 flyby unexpectedly resulted in observation of two “wake” crossings referred to as Events 1 and 2. Event 2 was evidently caused by draped magnetosphere field lines, which are scavenging pickup ions from Titan's induced magnetopause boundary with outward flux ∼2×106 ions/cm2/s. The composition of this out flow is dominated by H2+ and H+ ions. Ionospheric flow away from Titan with ion flux ∼7×106 ion/cm2/s is observed for Event 1. In between Events 1 and 2 are high energy field aligned flows of magnetosphere protons that may have been accelerated by the convective electric field across Titan's topside ionosphere. T18 observations are much closer to Titan than T9, allowing one to probe this type of interaction down to altitudes ∼950 km. Comparisons with previously reported hybrid simulations are made.  相似文献   
157.
158.
Under the current framework embodied in the Kyoto Protocol and envisaged for future multilateral agreements, Annex I parties are obliged to limit their economy-wide GHG emissions and accept responsibility for exceeding their targets through various flexible mechanisms. The predominant sources of agricultural GHGs, which represent about 8% of total Annex I emissions, are methane and nitrous oxide from livestock. Efforts to reduce livestock emissions have so far been limited due to disagreements over the abatement potential, technical feasibility, and cost-effectiveness of the policy instruments available, including market-based measures. Two key challenges facing the application of market-based measures to livestock emissions are evaluated: first, to design a policy framework that appropriately aligns the measurement of emissions, the abatement options, and the incentives facing livestock producers; second, to address the risk of leakage and economic regrets that arise from unilateral domestic policy action. Particular attention is given to the policy developments in New Zealand and the lessons learnt from its experience. The challenges of applying market-based measures to livestock emissions are surmountable, but require innovative policy responses.  相似文献   
159.
Gravity and magnetic analysis provide an opportunity to deduce and understand to a large extent the stratigraphy, structure and shape of the substructure. Euler deconvolution is a useful tool for providing estimates of the localities and depth of magnetic and gravity sources. Wavelet analysis is an interesting tool for filtering and improving geophysical data. The application of these two methods to gravity and magnetic data of the Liberia Basin enable the definition of the geometry and depth of the subsurface geologic structures. The study reveals the basin is sub-divided and the depth to basement of the basin structure ranges from about 5 km at its North West end to 10 km at its broadest section eastward. Magnetic data analysis indicates shallow intrusives ranging from a depth of 0.09 km to 0.42 km with an average depth of 0.25 km along the margin. Other intrusives can be found at average depths of 0.6 km and 1.7 km respectively within the confines of the basin. An analysis of the gravity data indicated deep faults intersecting the transform zone.  相似文献   
160.
Restoration of offshore marine habitats is a relatively new concept, with attempts in the European Union being largely instigated by requirements of various strategic directives. In this experiment, we investigate the practicality and effectiveness of gravel seeding, using a commercial aggregate dredging vessel, in order to recreate a gravel habitat. The experimental design consisted of a Treatment and Control site, both within an area of historic dredging characterised by an overburden of sand, and a gravel dominated Reference site. All sites were surveyed, using a combination of acoustic, camera and grab techniques, 2 months before, and then at 0, 12 and 22 months after the deposition of 4444 m3 of gravel dominated sediments within the Treatment site. Although financial and practical constraints limited replication of the Treatment to one area, and so precluded strong statistical conclusions, our results suggested that the technique was both practically feasible, and successful in terms of returning the physical and biological attributes at the Treatment site to a state more representative of gravelly substrata in the wider, un-impacted environment.  相似文献   
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