胶州湾及青岛近海微表层与次表层中二甲基硫(DMS)与二甲巯基丙酸(DMSP)的浓度分布

以胶州湾及青岛近海为研究区域,利用吹扫-捕集气相色谱法研究了二甲基硫(DMS)和二甲巯基丙酸(DMSP,分为溶解态DMSPd和颗粒态DMSPp)在微表层与次表层中的浓度以及它们在微表层中的富集行为。结果表明,DMS、DMSPd和DMSPp在微表层中的浓度高于次表层,它们在微表层中的富集因子分别为1.17、1.84和1.51。研究发现,DMS及DMSPp浓度与叶绿素a(Chl-a)浓度有很好的相关性,但它们的周日变化与Chl-a并不完全同步。DMS/Chl-a和DMSPp/Chl-a的比值在次表层和微表层分别为4.35、13.47mmol/g和3.99、15.88mmol/g。胶州湾及青岛近海生态环境受人为活动干扰严重,使本海域DMS含量较高,从而贡献出较大的DMS海-气通量。     

基于信息扩散原理的渤、黄海沿岸风暴潮灾害风险分析

根据收集的渤、黄海沿岸主要海洋站(塘沽、羊角沟、烟台、威海、乳山口、青岛和日照)1950年以来各年最高潮位资料(个别站位资料样本较小),应用能优化处理小样本的基于信息扩散原理的模糊风险评估模型,对渤、黄海沿岸各海洋站年最高潮位的多年一遇极值情况进行了超越概率计算,并与《港口工程技术规范》推荐的极值I型(Gumbel曲线)方法进行比较。除羊角沟站误差3%外,其它站误差均在2%及以下,表明文中基于信息扩散原理的风险评估模型在兼顾小样本条件下所给结果是比较可靠的。这对于潮位等水文实测资料短缺的新建或拟建工程区进行工程水文要素设计重现期的推算将有较好的帮助。     

Planning the use of fish for food security in the Pacific

Fish is a mainstay of food security for Pacific island countries and territories (PICTs). Recent household income and expenditure surveys, and socio-economic surveys, demonstrate that subsistence fishing still provides the great majority of dietary animal protein in the region. Forecasts of the fish required in 2030 to meet recommended per capita fish consumption, or to maintain current consumption, indicate that even well-managed coastal fisheries will only be able to meet the demand in 6 of 22 PICTs. Governments of many PICTs will need to increase local access to tuna, and develop small-pond aquaculture, to provide food security. Diversifying the supply of fish will also make rural households in the Pacific more resilient to natural disasters, social and political instability, and the uncertainty of climate change.     

Assessment of recreation activity and its application to integrated management and spatial planning for Cork Harbour, Ireland

The coastal environment is commonly the location for multiple human activities, of which recreation is just one. The coastal and marine sector has experienced nascent growth and this trend is likely to continue into the foreseeable future; the projected growth of the sector will impact coastal and marine resources, whilst also placing demands on those tasked with planning and managing the coastal environment. In Ireland, this presents particular challenges for coastal local authorities, as the principal planning consent body. In order to address these emerging challenges an innovative working partnership was developed between the research community and local authority to examine marine recreation in Cork Harbour, situated on the southern coast of Ireland. A programme of work was devised to identify data gaps in terms of: baseline information; user attitudes and perceptions towards existing management framework and facilities for recreation; interactions between different user groups; and, spatial distribution of recreational activities. The results of the assessment provided an improved understanding of the current coastal recreational situation, have value as input to spatial planning and contribute to the development of an integrated management plan for Cork Harbour.     

Fisheries and coastal governance as a wicked problem

Inspired by Rittel and Webber [Dilemmas in a general theory of planning. Policy Sciences 1973;4:155–69], it is argued that fisheries and coastal governance is confronted with problems that are inherently “wicked.” Problems are wicked (as opposed to “tame”) when they are difficult to define and delineate from other and bigger problems and when they are not solved once and for all but tend to reappear. Wicked problems have no technical solution, it is not clear when they are solved, and they have no right or wrong solution that can be determined scientifically. Instead, for wicked problems governance must rely on the collective judgment of stakeholders involved in a process that is experiential, interactive and deliberative. In this paper, the wicked problem is identified as a governability issue, recognizing that there are limitations to how rational and effective fisheries and coastal governance can possibly be. The paper offers a framework which could help us locate the wicked problems within the fisheries and coastal governance system, as well as examine their governability.     

Safety evaluation of breakwaters based on physical and numerical modelling

This paper highlights an integration of physical and numerical methods in evaluating a soil-breakwater system in coastal engineering. Centrifuge modelling is used to reproduce field phenomena and confirm the effectiveness of numerical methods. Numerical simulation incorporating finite element and limit equilibrium analysis is employed to explain the test results quantitatively and evaluate the deformation and stability of the complex soil-structure system. The results of physical and numerical simulation show that the proposed approaches work well and provide useful basis for potential applications to other coastal structures.     

Increasing wave heights and extreme value projections: The wave climate of the U.S. Pacific Northwest

Deep-water wave buoy data offshore from the U.S. Pacific Northwest (Oregon and Washington) document that the annual averages of deep-water significant wave heights (SWHs) have increased at a rate of approximately 0.015 m/yr since the mid-1970s, while averages of the five highest SWHs per year have increased at the appreciably greater rate of 0.071 m/yr. Histograms of the hourly-measured SWHs more fully document this shift toward higher values over the decades, demonstrating that both the relatively low waves of the summer and the highest SWHs generated by winter storms have increased. Wave heights associated with higher percentiles in the SWH cumulative distribution function are shown to be increasing at progressively faster rates than those associated with lower percentiles. This property is demonstrated to be a direct result of the probability distributions for annual wave climates having lognormal- or Weibull-like forms in that a moderate increase in the mean SWH produces significantly greater increases in the tail of the distribution. Both the linear regressions of increasing annual averages and the evolving probability distribution of the SWH climate, demonstrating the non-stationarity of the Pacific Northwest wave climate, translate into substantial increases in extreme value projections, important in coastal engineering design and in quantifying coastal hazards. Buoy data have been analyzed to assess this response in the wave climate by employing various time-dependent extreme value models that directly compute the progressive increases in the 25- to 100-year projections. The results depend somewhat on the assumptions made in the statistical procedures, on the numbers of storm-generated SWHs included, and on the threshold value for inclusion in the analyses, but the results are consistent with the linear regressions of annual averages and the observed shifts in the histograms.     

Calculation of beach change under interacting cross-shore and longshore processes

This paper presents a mathematical approach and numerical model that simulates beach and dune change in response to cross-shore processes of dune growth by wind and dune erosion by storms, and by gradients in longshore sand transport that will alter shoreline position. Sub-aerial transport processes are represented, whereas sub-aqueous transport is neglected. The system is tightly coupled morphologically, with the berm playing a central role. For example, the potential for sand to be transported to the dune by wind depends on berm width, and sand lost in erosion of the dune during storms can widen the berm. Morphologic equilibrium considerations are introduced to improve reliability of predictions and stability of the non-linear model. An analytical solution is given under simplification to illustrate properties of the model. Sensitivity tests with the numerical solution of the coupled equations demonstrate model performance, with one test exploring beach and dune response to potential increase in storm-wave height with global warming. Finally, the numerical model is applied to examine the consequences of groin shortening at Westhampton Beach, Long Island, New York, as an alternative for providing a sand supply to the down-drift beach. Results indicate that the sand will be released over several decades as the shoreline and dune move landward in adjustment to the new equilibrium condition with the shortened groins.     

A virtual laboratory for stability tests of rubble-mound breakwaters

The prediction of rubble-mound breakwater damage under wave action has usually relied on costly and time-consuming physical model tests. In this work, artificial neural networks (ANNs) are applied to estimate the outcome of a physical model throughout an experimental campaign comprising of 127 stability tests. In order to choose the network best suited to the problem data, five different activation function options and 38 network architectures are compared. The good agreement found between the physical model and the neural network shows that an ANN may well serve as a virtual laboratory, reducing the number of physical model tests necessary for a project.     

Air–sea carbon dioxide fluxes in the coastal southeastern tropical Pacific

Comprehensive sea surface surveys of the partial pressure of carbon dioxide (pCO₂) have been made in the upwelling system of the coastal (0–200 km from shore) southeastern tropical Pacific since 2004. The shipboard data have been supplemented by mooring and drifter based observations. Air–sea flux estimates were made by combining satellite derived wind fields with the direct sea surface pCO₂ measurements. While there was considerable spatial heterogeneity, there was a significant flux of CO₂ from the ocean to the atmosphere during all survey periods in the region between 4° and 20° south latitude. During periods of strong upwelling the average flux out of the ocean exceeded 10 moles of CO₂ per square meter per year. During periods of weaker upwelling and high productivity the CO₂ evasion rate was near 2.5 mol/m²/yr. The average annual fluxes exceed 5 mol/m²/yr. These findings are in sharp contrast to results obtained in mid-latitude upwelling systems along the west coast of North America where the average air–sea CO₂ flux is low and can often be from the atmosphere into the ocean. In the Peruvian upwelling system there are several likely factors that contribute to sea surface pCO₂ levels that are well above those of the atmosphere in spite of elevated primary productivity: (1) the upwelling source waters contain little pre-formed nitrate and are affected by denitrification, (2) iron limitation of primary production enhanced by offshore upwelling driven by the curl of the wind stress and (3) rapid sea surface warming. The combined carbon, nutrient and oxygen dynamics of this region make it a candidate site for studies of global change.