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1.
The present study evaluates future storm surge risk due to tropical cyclones (typhoons) in East Asia. A state-of-the-art atmospheric general circulation model (GCM) outputs are employed as the driving force for simulating storm surges associated with the projected changes in climate. The reproducibility of tropical cyclone (TC) characteristics from the GCM in the Northwest Pacific (NWP) is confirmed by comparing with the observed best track data, and future typhoon changes were presented. Storm surge simulation is carried out for East Asia, with the finest nested domain on the Japanese coast. The probability of maximum storm surge heights with specified return periods is determined using extreme value statistics. We show a strong regional dependency on future changes of severe storm surges.  相似文献   
2.
The computer model for near shore wave propagation,SWAN,was used to study wave climates in Liverpool Bay,northwest England with various input parameters,including bottom friction factor,white capping,wind drag formulation and effects of tidal modulations.Results were compared with in-situ measurements and reveal the impacts from these inputs on the predictions of wave height and propagation distributions.In particular,the model results were found very sensitive to different input formulations,and tend to underestimate the wave parameters under storm conditions in comparison with the observations.It is therefore important to further validate the model against detailed field measurements,particularly under large storms that are often of the primary concern.  相似文献   
3.
This paper highlights the tension between advocacy for ‘Blue growth’ in maritime policy and efforts to safeguard future economic growth via the Marine Strategy Framework Directive. In 2015, policy-makers withdrew three of four proposed Marine Conservation Zones (MCZs) in the Irish Sea from consideration for designation, due to concerns that they could significantly impact on the fisheries sector in Northern Ireland because they overlap with prawn fishing grounds in the Irish Sea. Although research has quantified the potential impact upon fishing vessels, none has quantified the impact upon the fisheries sector nor assessed the significance of this impact. Arguably, MCZ designations (or lack thereof) based on the ‘significance’ of an impact require robust underpinning evidence. This paper reports the findings of an Economic Impact Assessment, which has quantified the impact of a decline in landings upon the Northern Ireland fisheries sector and regional economy (data which is currently absent from the evidence base for the MCZ designation process in England). It finds that this will incur job losses in three fishing ports in Northern Ireland, but is unlikely to have a significant impact upon Northern Ireland's fisheries sector and regional economy in terms of jobs and Gross Value Added (GVA). In the worst case, the resulting economic impact is a decrease of £1.05–1.12 m/year GVA in Northern Ireland, which is 1.1% of the contribution of fishing and fish processing to the regional economy. Economic significance assessments, using this methodology, may be useful in supporting the evidence base underpinning MCZ designation and other aspects of marine planning.  相似文献   
4.
A pilot Coastal Observatory has been established in Liverpool Bay which integrates (near) real-time measurements with coupled models and whose results are displayed on the web. The aim is to understand the functioning of coastal seas, their response to natural forcing and the consequences of human activity. The eastern Irish Sea is an apt test site, since it encompasses a comprehensive range of processes found in tidally dominated coastal seas, including near-shore physical and biogeochemical processes influenced by estuarine inflows, where both vertical and horizontal gradients are important. Applications include hypernutrification, since the region receives significantly elevated levels of nutrient inputs, shoreline management (coastal flooding and beach erosion/accretion), and understanding present conditions to predict the impact of climate change (for instance if the number and severity of storms, or of high or low river flows, change). The integrated measurement suite which started in August 2002 covers a range of space and time scales. It includes in situ time series, four to six weekly regional water column surveys, an instrumented ferry, a shore-based HF radar system measuring surface currents and waves, coastal tide gauges and visible and infra-red satellite data. The time series enable definition of the seasonal cycle, its inter-annual variability and provide a baseline from which the relative importance of events can be quantified. A suite of nested 3D hydrodynamic, wave and ecosystem models is run daily, focusing on the observatory area by covering the ocean/shelf of northwest Europe (at 12-km resolution) and the Irish Sea (at 1.8 km), and Liverpool Bay at the highest resolution of 200 m. The measurements test the models against events as they happen in a truly 3D context. All measurements and model outputs are displayed freely on the Coastal Observatory website () for an audience of researchers, education, coastal managers and the public.  相似文献   
5.
Marine radars mounted on ships can provide remarkable insights into ocean behaviour from distances of several kilometres, placing other in situ observations and the environment around a ship into a wider oceanographic context. It has been known for some time that it is possible to map shallow water bathymetry and currents using radar image sequences recorded from shore based stations. However, a long standing question from military and hydrographic communities has been whether such techniques can be applied to radar data collected by moving vessels. If so, this presents the possibility of mapping large areas of shallow or coastal seas (albeit with a somewhat coarse horizontal resolution of 50–100 m) prior to the surveying vessel actually having to travel into potentially uncharted or dangerous shallow water areas. Trial sets of radar data were recorded by the Canadian Forces Auxiliary Vessel Quest using a Wamos radar digitiser connected to a Decca navigation radar during a number of deployments around Nova Scotia in 2008 and 2009. Georeferencing corrections derived from the existing ship navigation systems were sufficient to allow the application of the existing depth inversion analysis designed for static radar installations. This paper presents the results of bathymetry analyses of two datasets recorded from CFAV Quest while the vessel was travelling at speeds of up to 14 knots. The bathymetry derived from the radar data compare favourably with independent surveys and with the on-board echo sounder to depths of approximately 50 m.  相似文献   
6.
7.
The effectiveness of institutional arrangements and policies for governance has become a key question within the sustainability paradigm, not least in coastal areas which have unique issues and jurisdictions across the land–sea interface. In the UK, approximately 60 non-statutory coastal management initiatives have been established at the local/regional level since the 1990s, based on a variety of programmes and projects. Proposals for a UK Marine Bill have raised questions about the role of non-statutory initiatives in the system of governance. The traditional sectoral approach to management and planning is being modified due to the pressure of increased human activities, but doubts exist about what effective contribution local and regional partnerships can make. The paper reports extensive examples of Integrated Coastal Management initiatives engaging institutions and society to produce outputs which have transformed management, promoting long-term, collaborative, participatory and ecologically sustainable approaches. The paper concludes that there are demonstrable benefits in taking a partnership approach to coastal management at a local level, yet these forms of planning and management are not widely accepted or embedded within the current system of governance.  相似文献   
8.
Erosion of volcanic islands ultimately creates shallow banks and guyots, but the ways in which erosion proceeds to create them over time and how the coastline retreat rate relates to wave conditions, rock mass strength and other factors are unclear. The Capelinhos volcano was formed in 1957/58 during a Surtseyan and partly effusive eruption that added an ~2.5 km2 tephra and lava promontory to the western end of Faial Island (Azores, central North Atlantic). Subsequent coastal and submarine erosion has reduced the subaerial area of the promontory and created a submarine platform. This study uses historical information, photos and marine geophysical data collected around the promontory to characterize how the submarine platform developed following the eruption. Historical coastline positions are supplemented with coastlines interpreted from 2004 and 2014 Google Earth images in order to work out the progression of coastline retreat rate and retreat distance for lava- and tephra-dominated cliffs. Data from swath mapping sonars are used to characterize the submarine geometry of the resulting platform (position of the platform edge, gradient and morphology of the platform surface). Photographs collected during SCUBA and ROV dives on the submarine platform reveal a rugged surface now covered with boulders. The results show that coastal retreat rates decreased rapidly with time after the eruption and approximately follow an inverse power-law relationship with coastal retreat distance. We develop a finite-difference model for wave attenuation over dipping surfaces to predict how increasing wave attenuation contributed to this trend. The model is verified by reproducing the wave height variation over dipping rock platforms in the UK (platform gradient 1.2° to 1.8°) and Ireland (1.8°). Applying the model to the dipping platform around Capelinhos, using a diversity of cliff resistance predicted from known lithologies, we are able to predict erosion rate trends for some sectors of the edifice. We also explore wider implications of these results, such as how erosion creates shallow banks and guyots in reef-less mid-oceanic archipelagos like the Azores. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd.  相似文献   
9.
Knowledge of the likely future wind, wave and surge climate in Liverpool Bay is of importance for coastal flood defence management. We examine a 140-year time series (1960–2100) of wind and wave model projections at the WaveNet buoy location in Liverpool Bay and also of surge model projection at two ports in Liverpool Bay, namely Liverpool and Heysham. To this end we use model projections from the UK Climate Projections 09 (UKCP09) programme. We use a medium emissions scenario ensemble from the HadCM3 climate model sensitivity tests. A continental shelf model (CS3) with ~12 km resolution was used to separately simulate the waves and the surge. The models are forced by hourly wind and pressure data from the Met Office (Hadley Centre) regional climate model (RCM). Swell wave boundary conditions are generated over the full Atlantic using global climate model (GCM) winds. Analysis of significant changes in the statistics over time shows that there is little change in extreme wave and surge conditions in Liverpool Bay. Although there is a slight increase in the severity of the most extreme events, the frequency of extreme wind and wave events is slightly reduced, while the frequency of extreme surge events slightly increases over the 140-year period. From the model projections, we find that the trends in the local wind are directly reflected in the wave field within Liverpool Bay. The trends in the skew surge projections deviate slightly from those in the wind patterns.  相似文献   
10.
Sea surface temperature satellite imagery and a regional hydrodynamic model are used to investigate the variability and structure of the Liverpool Bay thermohaline front. A statistically based water mass classification technique is used to locate the front in both data sets. The front moves between 5 and 35 km in response to spring–neap changes in tidal mixing, an adjustment that is much greater than at other shelf-sea fronts. Superimposed on top of this fortnightly cycle are semi-diurnal movements of 5–10 km driven by flood and ebb tidal currents. Seasonal variability in the freshwater discharge and the density difference between buoyant inflow and more saline Irish Sea water give rise to two different dynamical regimes. During winter, when cold inflow reduces the buoyancy of the plume, a bottom-advected front develops. Over the summer, when warm river water provides additional buoyancy, a surface-advected plume detaches from the bottom and propagates much larger distances across the bay. Decoupled from near-bed processes, the position of the surface front is more variable. Fortnightly stratification and re-mixing over large areas of Liverpool Bay is a potentially important mechanism by which freshwater, and its nutrient and pollutant loads, are exported from the coastal plume system. Based on length scales estimated from model and satellite data, the erosion of post-neap stratification is estimated to be responsible for exporting approximately 19% of the fresh estuarine discharge annually entering the system. Although the baroclinic residual circulation makes a more significant contribution to freshwater fluxes, the episodic nature of the spring–neap cycle may have important implications for biogeochemical cycles within the bay.  相似文献   
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