Nobuo Mimura

VELOCITY FIELD UNDER PLUNGING WAVES

More than 150 tests have been analyzed in order to describe the dynamically stable profiles of rock slopes and gravel beaches under wave attack. Relationships between profile parameters and boundary conditions have been established. These relationships have been used to develop a computer program. This program is able to predict the profiles of slopes with an arbitrary shape under varying wave conditions, such as those found in storm surges and during the tidal period.This paper investigates the utility of winds obtainable from a numerical weather prediction model for driving a spectral ocean-wave model in an operational mode. Wind inputs for two operational spectral wave models were analyzed with respect to observed winds at three locations in the Canadian east coast offshore. Also, significant wave heights obtainable from the two spectral models were evaluated against measured wave data at these locations. Based on this analysis, the importance of appropriate wind specification for operational wave analysis and forecasting is demonstrated.

The changing nature of extreme weather and climate events: risks to sustainable development

This paper discusses climate-development linkages, with a focus on developing countries but also drawing lessons from the experiences of developed countries. Increases in weather and climate extremes leading to natural disasters have been observed in recent decades. Such events are impeding economic and social development in developing countries, as are socio-economic changes that increase their exposure and as well as the likelihood of mal-adaptation. For the Pacific Islands region, the most recent decade has been somewhat anomalous, with the marked absence of El Niño conditions resulting in fewer people being affected by natural disasters. Further increases in these extreme events are anticipated as a result of global warming, imposing still further barriers to sustainable development. However, integrating appropriate adaptation measures, including disaster risk-reduction measures, into development policies and plans provides developing countries with the opportunity to reduce socio-economic risks associated with extreme weather and climate events. This will help ensure the longer-term viability of development, despite a changing climate. Emphasis should be on no-regrets interventions.

Sea-level rise caused by climate change and its implications for society

Sea-level rise is a major effect of climate change. It has drawn international attention, because higher sea levels in the future would cause serious impacts in various parts of the world. There are questions associated with sea-level rise which science needs to answer. To what extent did climate change contribute to sea-level rise in the past? How much will global mean sea level increase in the future? How serious are the impacts of the anticipated sea-level rise likely to be, and can human society respond to them? This paper aims to answer these questions through a comprehensive review of the relevant literature. First, the present status of observed sea-level rise, analyses of its causes, and future projections are summarized. Then the impacts are examined along with other consequences of climate change, from both global and Japanese perspectives. Finally, responses to adverse impacts will be discussed in order to clarify the implications of the sea-level rise issue for human society.

Vulnerability, Risk and Adaptation Assessment Methods in the Pacific Islands Region: past approaches, and considerations for the future

Over two decades of vulnerability assessments have shown the Pacific Islands region to be one of the regions most at risk to the adverse consequences of climate change. Pacific Island countries have shown strong leadership in characterising the challenges of climate change, both nationally and for the region as a whole, and in identifying the most appropriate responses. This paper reviews the various Vulnerability, Risk and Adaptation (VRiA) Assessment Methods and Tools that have been used across the Pacific Islands region, with an emphasis on the past two decades. The aim is to identify the approaches that are best suited to the region, and to develop a common understanding and principles that may be relevant and useful to harmonising the assessment of vulnerability and risk, and of adaptation options across the region. Even though assessments undertaken in the Pacific Islands region tend to share the common objective of reducing vulnerabilities and risks, practitioners in the Pacific are using numerous approaches, methods and tools to assess vulnerabilities and identify possible adaptation interventions. No one approach will address all needs and accommodate all capacities. Rather, several successful approaches, methods and tools are identified. The paper also identifies and assesses the approaches, methods and tools that have merit for further use, without or with further improvements. Lessons learned as well as success stories and success factors are documented. These findings are reflected in principles designed to assist harmonisation of approaches to VRiA assessment. These principles, in turn, influence the development of a proposed higher-level framework and approach for VRiA assessments. It accommodates the various approaches, methods and tools commonly used with success in the Pacific.

OSCILLATORY BOUNDARY LAYER FLOW OVER RIPPLED BEDS

This report will update the coastal zone practitioner on the National Flood Insurance Program (NFIP) as it affects the implementation of manmade changes along the coastline. It is our intent to place in proper perspective this fast-changing and often difficult to interpret national program. Readers will achieve an overall understanding of the NFIP on the coast, and will be in a position to apply the programs requirements in their efforts. We will begin with a history of the application of the NFIP to the coastal zone. The history of the problems encountered will lead into current regulations, methodologies, and the changes the Federal Emergency Management Agency plans for the future.The spatial variability of the nearshore wave field is examined in terms of the coherence functions found between five closely spaced wave gages moored off the North Carolina coast in 17 meters depth. Coherence was found to rapidly decrease as the separation distance increased, particularly in the along-crest direction. This effect is expressed as nondimensional coherence contours which can be used to provide an estimate of the wave coherence expected between two spatial positions.Prediction of depositional patterns in estuaries is one of the primary concerns to coastal engineers planning major hydraulic works. For a well-mixed estuary where suspended load is the dominant transport mode, we propose to use the divergence of the distribution of the net suspended load to predict the depositional patterns. The method is applied to Hangzhou Bay, and the results agree well qualitatively with measured results while quantitatively they are also of the right order of magnitude.

Understanding and managing global change in small islands

Climate variability and change, associated changes in sea level, ocean acidification and surface warming, extreme events such as tropical cyclones and tsunamis, and the quality and quantity of freshwater resources are among the major environmental issues related to the sustainable development of small islands, including small island developing states (SIDS). In addition to natural change and hazards, principal sources of stress on small islands include changing social, demographic, economic, cultural, and governance conditions and maladaptive local development initiatives. As global pressures increase, including those related to climate change, the ability to cope with the adverse consequences of complex change may be compromised increasingly by limits to adaptive capacity, unsustainable development practices, institutional barriers, and other governance challenges. Island communities are social-ecological systems and their resilience in the face of uncertain futures (environmental, economic, and others) and surprises (extreme events) is a key element of sustainability (Kates et al. 2000; Adger 2006; Adger et al. 2005). Small island developing states and small islands within larger states are physical, ecological, and social entities with distinctive attributes related to their insularity, remoteness, size, geographic setting, climate, culture, governance, and economy (e.g. Pelling and Uitto 2001; Mimura et al. 2007; Hay 2013; Forbes et al. 2013). Yet despite the sense of separation that attends the experience of small islands, global change in a variety of forms impinges directly or indirectly on the environment and sustainability of these island communities. As a group, they pose some of the most striking challenges to sustainability science. Low-lying island states, such as the Maldives and Tuvalu, face pressing concerns about the limits to habitability under accelerated sea-level rise, the result of a warming global climate. Ocean warming and acidification pose threats to the conservation of reef corals and the stability and resilience of coral reefs under rising sea level (IPCC 2007). Together with concerns about freshwater resources, these environmental threats exacerbate challenges related to small size and remoteness, demographic pressures, small markets and limited economic opportunities, high per-capita infrastructure costs, reliance on external finance, limited technical capacity (including capacity for disaster response, recovery, and risk reduction), and cultural transformation through processes such as J. E. Hay (&) N. Mimura Institute for Global Change Adaptation Science (ICAS), Ibaraki University, Environment Research Laboratory Building, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan e-mail: johnhay@ihug.co.nz

REGULATION OF NEARSHORE CIRCULATION BY SUBMERGED BREAKWATER FOR SHORE PROTECTION

A study of alternatives including a shoreline evolution numerical modelization has been carried out in order to both diagnose the erosion problem at the beaches located between Cambrils Harbour and Pixerota delta (Tarragona, Spain) and select nourishment alternatives.

RESPONSES OF COASTAL TOPOGRAPHY TO SEA-LEVEL RISE

A study of alternatives including a shoreline evolution numerical modelization has been carried out in order to both diagnose the erosion problem at the beaches located between Cambrils Harbour and Pixerota delta (Tarragona, Spain) and select nourishment alternatives.

Impacts on Infrastructure and Socio-economic System

This chapter deals with the impacts of global warming and climate change on the human society. Infrastructures and socio-economic activities are considered to be sensitive to rises in atmospheric temperature and mean sea level, and changes in rainfall and typhoon caused by global warming. Since Japan has concentrated its population and industries to low-lying coastal plains, the effects of sea-level rise and intensified typhoons and storm surges will be severe. In addition, the effects of global warming spread in a wide area of highly industrialized society, such as human life, traffic systems and industries, through the adverse effects on the supply systems of fresh water and energy. Though the entire picture of such effects has not been studied yet, it was tried to review existing studies to extract as quantitative information as possible. When quantitative information was not available, possible impacts were estimated on the qualitative basis.

Assessment of insurance for paddy production: a case study in Indonesia

The present study demonstrated the importance of designing insurance as a part of broader risk management, using pilot insurance for rice farmers in East Java, Indonesia, as a case. An independent-sample t-test, using historical data on the areas of monthly rice harvest failure at regency level for the recent 10 years, finds that harvest failure during the rainy seasons in a group of the regencies located in the Bengawan Solo River Basin is significantly greater than the other group consisting of the remaining regencies in the province. This is due to frequent floods, which are largely attributed to the declining function of the Wonogiri reservoir as the primary flood control facility. It suggests the necessity of risk prevention measures, such as those to pump out dead storage and upgrade spillway capacity, to allow insurance to work in the basin. The present study also investigated a feasibility of weather index insurance. It compares the correlation coefficients and statistical significance of monthly rice harvest failure between 29 regencies in the province on one hand, and those of monthly rainfall on the other. It finds that rice harvest failure has higher spatial dependency than rainfall, indicating a potential problem of a basis risk.