Assessing climate change impacts,sea level rise and storm surge risk in port cities: a case study on Copenhagen

This study illustrates a methodology to assess the economic impacts of climate change at a city scale and benefits of adaptation, taking the case of sea level rise and storm surge risk in the city of Copenhagen, capital of Denmark. The approach is a simplified catastrophe risk assessment, to calculate the direct costs of storm surges under scenarios of sea level rise, coupled to an economic input–output (IO) model. The output is a risk assessment of the direct and indirect economic impacts of storm surge under climate change, including, for example, production and job losses and reconstruction duration, and the benefits of investment in upgraded sea defences. The simplified catastrophe risk assessment entails a statistical analysis of storm surge characteristics, geographical-information analysis of population and asset exposure combined with aggregated vulnerability information. For the city of Copenhagen, it is found that in absence of adaptation, sea level rise would significantly increase flood risks. Results call for the introduction of adaptation in long-term urban planning, as one part of a comprehensive strategy to manage the implications of climate change in the city. Mitigation policies can also aid adaptation by limiting the pace of future sea level rise.     

Storm surge evolution and its relationship to climate oscillations at Duck,NC

Coastal communities experience increased vulnerability during storm surge events through the risk of damage to coastal infrastructure, erosion/deposition, and the endangerment of human life. Policy and planning measures attempt to avoid or mitigate storm surge consequences through building codes and setbacks, beach stabilization, insurance rates, and coastal zoning. The coastal emergency management community and public react and respond on shorter time scales, through temporary protection, emergency stockpiling, and evacuation. This study utilizes time series analysis, the Kolmogorov-Smirnov (K-S) test, Pearson’s correlation, and the generalized extreme value (GEV) theorem to make the connection between climate oscillation indices and storm surge characteristics intra-seasonally to inter-annually. Results indicate that an El Niño (+ENSO), negative phase of the NAO, and positive phase of the PNA pattern all support longer duration and hence more powerful surge events, especially in winter. Increased surge duration increases the likelihood of extensive erosion, inland inundation, among other undesirable effects of the surge hazard.     

Climate change adaptation implications for drought risk mitigation: a perspective for India

There is a growing evidence that the climate change do has implications for drought vulnerable India with studies projecting future possible reductions in monsoon related rainfall in the country. The existing drought risk mitigation and response mechanisms were looked into and gaps were identified by drawing lessons from previous disasters and response mechanisms. In absence of reliable climate predictions at the scales that make them useful for policy level planning, the emphasis was on identifying no-regret adaptation options those would reduce current vulnerabilities while mainstreaming the adaptation in the long run. The most notable climate change implications for the drought vulnerable India are the enhanced preparedness with due emphasis to the community based preparedness planning, reviewing the existing monsoon and drought prediction methodologies, and establishing drought monitoring and early warning systems in association with a matching preparedness at the input level.     

REFINED RISK ASSESSMENT OF STORM SURGE DISASTER IN COASTAL PLAIN: A CASE STUDY OF PINGYANG COUNTY

As the risk of storm surge on coastal plains increases, the research on disaster risk assessment is fundamental for disaster management. Disaster risk assessment tends to develop towards the direction of refinement and it gradually plays a more important role. As regards the characteristics of storm tide disaster in coastal plain, the paper uses refined floodplain numerical model which combines typhoon, flood, astronomical tide and waves. The model also considers influencing factors of dike-breaking, micro-topography and buildings. Precise calculation is executed for the range and the submerged depth caused by floodplain flow in coastal plain. Based on 3S technology, disaster-bearing bodies are subdivided into the smallest unit of the ground object, and the vulnerability of these units is evaluated. Refined risk assessment of storm surge disaster for the coastal plain is obtained, and the detailed distribution of risk areas at different risk levels is achieved. These results can be widely applied in many fields, such as disaster prevention and mitigation, urban planning, industrial arrangement, disaster insurance and so on.     

珠江河口风暴潮对径流的敏感性研究:以台风“山竹”为例

径流-风暴潮相互作用可增大河口区风暴潮增水,增加风暴潮灾害风险。基于SCHISM模式建立了珠江河口风暴潮数值模型,以台风“山竹”为例,采用实测资料对模型计算结果进行验证,最高潮位相对误差在9%以内。设计了台风“山竹”实测径流与5年一遇洪水的对比试验,讨论了径流变化对河口风暴潮增水的影响,结果表明:河口口门站位风暴潮增水随径流量的增大而增大。径流增加对泗盛围、南沙等站位的风暴潮影响较大,在风暴潮增水达到最大值时影响最为显著。以径流动力作用为主的区域,当上游径流量增大时,对风暴潮增水起到负影响作用:如磨刀门水道,随着径流的增加,沿河道上溯的风暴潮增水逐渐减小,由灯笼山站3.22 m减小至马口站1.12 m。以潮汐动力作用为主的区域,当上游径流量增大时,对风暴潮增水起到正影响作用:如珠江干流,随着径流的增加,沿河道上溯的风暴潮增水逐渐增大,大虎站的最大增水值为3.44 m,中大站为4.24 m,从口门至后航道区域增大了0.8 m。      

Climate change and coastal flooding in Metro Boston: impacts and adaptation strategies

Sea level rise (SLR) due to climate change will increase storm surge height along the 825 km long coastline of Metro Boston, USA. Land at risk consists of urban waterfront with piers and armoring, residential areas with and without seawalls and revetments, and undeveloped land with either rock coasts or gently sloping beachfront and low-lying coastal marshes. Risk-based analysis shows that the cumulative 100 year economic impacts on developed areas from increased storm surge flooding depend heavily upon the adaptation response, location, and estimated sea level rise. Generally it is found that it is advantageous to use expensive structural protection in areas that are highly developed and less structural approaches such as floodproofing and limiting or removing development in less developed or environmentally sensitive areas.     

对一次温带气旋引发的渤海风暴潮过程的数值模拟

利用三维非静力中尺度大气模式—MM5（Version 3.7）输出的黄渤海海面风场和气压场预报资料,用三维斜压陆架海模式—HAMSOM对2008年8月22日温带气旋造成的渤海风暴潮过程进行了模拟,得到逐时的渤海增水场、渤海风暴潮流场,与验潮站的观测数据进行比较。结果表明：在渤海西部已经转西北风的情况下,塘沽出现了121 cm的高增水,造成这种现象的原因很复杂,其中远距离的气旋作用产生的北黄海海域偏东大风导致北黄海水体大量涌入渤海应该是一个主要原因。这也是今后预报业务中必须特别关注的产生风暴潮的重要因素。数值模拟的塘沽测站的风暴潮增水极值及增水过程都和实测值符合较好,本次过程中数值预报能够很好地模拟出这种特殊的风暴潮。在离岸风的情况下产生风暴潮,这仅靠预报员凭经验主观分析判断是很难的,数值预报可以弥补预报员主观分析的不足。     

An assessment of the physical impacts of sea-level rise and coastal adaptation: a case study of the eastern coast of Ghana

Sea-level rise is a major coastal issue in the 21st century because many of the world??s built assets are located in the coastal zone. Coastal erosion and flooding are serious threats along the coast of Ghana, particularly, the eastern coast where the Volta delta is located. Past human interventions, climate change and the resultant rise in sea-levels, increased storm intensity and torrential rainfall have been blamed for these problems. Accelerated sea-level rise and storm surge pose serious threat to coastal habitat, bio-diversity and socio-economic activities in the coastal zone of Ghana and elsewhere. There is the need for an holistic assessment of the impacts of sea-level rise on the coast zone in order to formulate appropriate adaptation policies and strategies to mitigate the possible effects. Using the eastern coast of Ghana as a case study, this paper assesses the physical impacts of accelerated sea level rise and storm surge on the coastal environment. It evaluates adaptation policies and plans that could be implemented to accommodate the present and any future impacts. Field investigation and Geographic Information System (GIS) are among the methods used for the assessment. The outcome of the assessment has provided comprehensive knowledge of the potential impacts of accelerated sea-level rise and storm surge on the eastern coast. It has facilitated identification of management units, the appraisal of alternate adaptation policies and the selection of the best policy options based upon the local conditions and environmental sustainability. Among other things, this paper reveals that the eastern coast of Ghana is highly vulnerable to accelerated sea-level rise and therefore, requires sustainable adaptation policies and plans to manage the potential impacts. It recommends that various accommodation policies, which enable areas to be occupied for longer before eventual retreat, could be adapted to accommodate vulnerable settlements in the eastern coast of Ghana.     

A method to estimate climate-critical construction materials applied to seaport protection

Climate adaptation for coastal infrastructure projects raises unique challenges because global-scale environmental changes may require similar projects to be completed in many locations over the same time frame. Existing methods to forecast resource demand and capacity do not consider this phenomenon of a global change affecting many localities and the resulting increased demand for resources. Current methods do not relate to the most up-to-date climate science information, and they are too costly or too imprecise to generate global, regional, and local forecasts of “climate-critical resources” that will be required for infrastructure protection. They either require too much effort to create the many localized designs or are too coarse to consider information sources about local conditions and structure-specific engineering knowledge. We formalized the concept of a “minimum assumption credible design” (MACD) to leverage available local information (topography/bathymetry and existing infrastructure) and the essential engineering knowledge and required construction materials (i.e., a design cross-section template). The aggregation of the resources required for individual local structures then forecasts the resource demand for global adaptation projects. We illustrate the application of the MACD method to estimate the demand for construction materials critical to protect seaports from sea-level-rise-enhanced storm surges. We examined 221 of the world’s 3,300+ seaports to calculate the resource requirements for a coastal storm surge protection structure suited to current upper-bound projections of two meters of sea level rise by 2100. We found that a project of this scale would require approximately 436 million cubic meters of construction materials, including cement, sand, aggregate, steel rebar, and riprap. For cement alone, ∼49 million metric tons would be required. The deployment of the MACD method would make resource forecasts for adaptation projects more transparent and widely accessible and would highlight areas where current engineering knowledge or material, engineering workforce, and equipment capacity fall short of meeting the demands of adaptation projects.     

Storm Surges in the Strait of Georgia Simulated with a Regional Model

The Strait of Georgia is a large, semi-enclosed body of water between Vancouver Island and the mainland of British Columbia connected to the Pacific Ocean via Juan de Fuca Strait at the south and Johnstone Strait at the north. During the winter months, coastal communities along the Strait of Georgia are at risk of flooding caused by storm surges, a natural hazard that can occur when a strong storm coincides with high tide. This investigation produces storm surge hindcasts using a three-dimensional numerical ocean model for the Strait of Georgia and the surrounding bodies of water (Juan de Fuca Strait, Puget Sound, and Johnstone Strait) collectively known as the Salish Sea. The numerical model employs the Nucleus for European Modelling of the Ocean architecture in a regional configuration. The model is evaluated through comparisons of tidal elevation harmonics and storm surge with observations. Important forcing factors contributing to storm surges are assessed. It is shown that surges entering the domain from the Pacific Ocean make the most significant contribution to surge amplitude within the Strait of Georgia. Comparisons between simulations and high-resolution and low-resolution atmospheric forcing further emphasize that remote forcing is the dominant factor in surge amplitudes in this region. In addition, local wind patterns caused a slight increase in surge amplitude on the mainland side of the Strait of Georgia compared with Vancouver Island coastal areas during a major wind storm on 15 December 2006. Generally, surge amplitudes are found to be greater within the Strait of Georgia than in Juan de Fuca Strait.     

离岸风背景下风暴潮异常增水特征分析

渤海湾在8月份出现由温带气旋引发高达518 cm的风暴潮属小概率事件。作者应用天气图、卫星云图、自动站观测资料及天津海洋局潮位资料,对2008年8月天津港发生的两次风暴潮异常增水过程进行了特征分析,得到气象因子对风暴潮的影响关系,为预报风暴潮提供依据;进一步探讨了在离岸风即西北风作用下产生风暴增水的条件和机制。结果表明,温带风暴潮过程增水强度大(最大增水121 cm)且持续时间长(达15小时);分析了气旋增水不同于台风增水的特点,并应用半封闭浅海湾中开尔文波传播理论分析了风暴潮产生的原因。     

On the economics of coastal adaptation solutions in an uncertain world

The economics of adaptation to climate change relies heavily on comparisons of the benefits and costs of adaptation options that can range from changes in policy to implementing specific projects. Since these benefits are derived from damages avoided by any such adaptation, they are critically dependent on the specification of a baseline. The current exercise paper reinforces this point in an environment that superimposes stochastic coastal storm events on two alternative sea level rise scenarios from two different baselines: one assumes perfect economic efficiency of the sort that could be supported by the availability of actuarially fair insurance and a second in which fundamental market imperfections significantly impair society’s ability to spread risk. We show that the value of adaptation can be expressed in terms of differences in expected outcomes damages only if the effected community has access to efficient risk-spreading mechanisms or reflects risk neutrality in its decision-making structure. Otherwise, the appropriate metric for measuring the benefits of adaptation must be derived from certainty equivalents. In these cases, increases in decision-makers’ aversion to risk increase the economic value of adaptations that reduce expected damages and diminish the variance of their inter-annual variability. For engineering and other adaptations that involve significant up-front expense followed by ongoing operational cost, increases in decision-makers’ aversion increase the value of adaptation and therefore move the date of economically efficient implementation closer to the present.     

Storm surge projections and implications for water management in South Florida

Water resource management in South Florida faces nearly intractable problems, in part due to weather and climate variability. Rising sea level and coastal storm surge are two phenomena with significant impacts on natural systems, fresh water supplies and flood drainage capability. However, decision support information regarding management of water resources in response to storm surge is not well developed. In an effort to address this need we analyze long term tidal records from Key West, Pensacola and Mayport Florida to extract surge distributions, to which we apply a nonlinear eustatic sea level rise model to project storm surge return levels and periods. Examination of climate connections reveals a statistically significant dependence between surge distributions and the Atlantic Multidecadal Oscillation (AMO). Based on a recent probabilistic model for AMO phase changes, we develop AMO-dependent surge distributions. These AMO-dependent surge projections are used to examine the flood control response of a coastal water management structure as an example of how climate dependent water resource forcings can be used in the formulation of decision support tools.     

0703温带气旋特大风暴潮数值模拟对比分析

为验证德国汉堡大学所开发的三维陆架模式HAMSOM(Hamburg Shelf Ocean Model)对渤海海域气旋风暴潮模拟的可行性和准确度, 并对不同来源气象数据的模拟结果进行比较, 分别使用T213和NCEP资料的风场和气压场数据, 运用HAM SOM模式对2007年3月4—5日发生在渤海和黄海北部的气旋风暴潮增水过程进行了数值模拟。模拟结果较好地反映出烟台、威海两站风暴潮增水过程的水位变化, 较准确地模拟出风暴潮在渤海、黄海北部的增水过程, 且T213资料比NCEP资料的模拟结果更接近实况, 该模式对研究和模拟渤海气旋风暴潮比较适用。     

烟台港风暴潮灾害及其预报

作者综合２０多年烟台港水文和气象资料，着重从气象与海洋的结合上探索了风暴潮的生成机制和一般特征，并应用１９８０－１９９２年的实测水文资料及数值天气预报资料，在天气形势分型的基础上，进行分类，选取因子，建立风暴潮客观，定量，自动化预报系统，投入烟台海洋气象台业务使用，有一定实用性。     

基于城市内涝仿真模型的天津风暴潮灾害评估

基于城市内涝仿真模型,根据天津沿海地区的地形、地貌特征以及排水系统等对城市内涝仿真模型进行改进,在沿海边界和河口设置时变水位,使得模型拓展到既能模拟暴雨产生的内涝,也能模拟由于风暴潮侵袭造成的淹没情景。该模型对天津沿海地区历史上典型风暴潮个例以及10年、20年、50年、100年一遇重现期风暴潮产生的积水范围和积水深度进行了模拟,并对2012年8月3日台风达维 (1210) 造成的天津沿海风暴潮进行了业务试应用。将历史风暴潮个例模拟结果以及2012年8月3日的评估结果与实际灾情进行对比,结果显示模型具有较好的模拟能力,可应用于风暴潮灾害的评估和预估业务中,为相关部门和行业提供决策参考。     

Integrated modeling of the dynamic meteorological and sea surface conditions during the passage of Typhoon Morakot

In August 2009, Typhoon Morakot caused massive flooding and devastating mudslides in the southern Taiwan triggered by extremely heavy rainfall (2777 mm in 4 days) which occurred during its passage. It was one of the deadliest typhoons that have ever attacked Taiwan in recent years. In this study, numerical simulations are performed for the storm surge and ocean surface waves, together with dynamic meteorological fields such as wind, pressure and precipitation induced by Typhoon Morakot, using an atmosphere–waves–ocean integrated modelling system. The wave-induced dissipation stress from breaking waves, whitecapping and depth-induced wave breaking, is parameterized and included in the wave–current interaction process, in addition to its influence on the storm surge level in shallow water along the coast of Taiwan. The simulated wind and pressure field captures the characteristics of the observed meteorological field. The spatial distribution of the accumulated rainfall within 4 days, from 00:00 UTC 6 August to 00:00 UTC 10 August 2009, shows similar patterns as the observed values. The 4-day accumulated rainfall of 2777 mm at the A-Li Shan mountain weather station for the same period depicted a high correlation with the observed value of 2780 mm/4 days. The effects of wave-induced dissipation stress in the wave–current interaction resulted in increased surge heights on the relatively shallow western coast of Taiwan, where the bottom slope of the bathymetry ranges from mild to moderate. The results also show that wave-breaking has to be considered for accurate storm surge prediction along the east coast of Taiwan over the narrow bank of surf zone with a high horizontal resolution of the model domain.     

Comparison of three methods for estimating the sea level rise effect on storm surge flooding

Two linear methods, including the simple linear addition and linear addition by expansion, and numerical simulations were employed to estimate storm surges and associated flooding caused by Hurricane Andrew for scenarios of sea level rise (SLR) from 0.15 m to 1.05 m with an interval of 0.15 m. The interaction between storm surge and SLR is almost linear at the open Atlantic Ocean outside Biscayne Bay, with slight reduction in peak storm surge heights as sea level rises. The nonlinear interaction between storm surges and SLR is weak in Biscayne Bay, leading to small differences in peak storm surge heights estimated by three methods. Therefore, it is appropriate to estimate elevated storm surges caused by SLR in these areas by adding the SLR magnitude to storm surge heights. However, the magnitude and extent of inundation at the mainland area by Biscayne Bay estimated by numerical simulations are, respectively, 22–24 % and 16–30 % larger on average than those generated by the linear addition by expansion and the simple linear addition methods, indicating a strong nonlinear interaction between storm surge and SLR. The population and property affected by the storm surge inundation estimated by numerical simulations differ up to 50–140 % from that estimated by two linear addition methods. Therefore, it is inappropriate to estimate the exacerbated magnitude and extent of storm surge flooding and affected population and property caused by SLR by using the linear addition methods. The strong nonlinear interaction between surge flooding and SLR at a specific location occurs at the initial stage of SLR when the water depth under an elevated sea level is less than 0.7 m, while the interaction becomes linear as the depth exceeds 0.7 m.     

Divergent options to cope with vulnerability in subsiding deltas

Net subsidence of most major deltas in the world and related vulnerability are thought to be increasing, and this is often linked causally to human activities. This paper examines this causality against a range of co-varying factors. We do so with a principal component analysis of co-variability of a range of geophysical and socio-economical indicators of 33 deltas mainly derived from the DIVA tool. Land potentially lost and people at risk of flooding are our indicators of vulnerability. The former correlated positively with maximum surge height and negatively with net sea level rise. The latter correlated positively with delta area, average river discharge, and maximum surge and negatively with net uplift (or subsidence). Thus, variation in societal vulnerability across deltas depends on short-term, instantaneous risks linked to lowland area, river discharge and storm surges rather than on longer-term, slow, net sea level rise. Delta management should focus on precautionary spatial planning, and on maintenance or restoration of historical sediment delivery and accretion rates. Especially larger deltas with high population densities combine a high risk with the potential to accommodate flood water and mitigate flooding risks. The deltas of the Yangtze-Kiang and Ganges-Brahmaputra share these characteristics. Here space should allow engineering of flood retention, sedimentation and diversion channels as well as refuges and safe economic hotspots. At the other end, in deltas with a high population density and limited space, like the Chao Praya, means for adaptation must be sought outside the delta proper. In deltas with low population densities, such as the Lena, Yukon or Fly, natural delta dynamics can prevail.     

Understanding climate coping as a basis for strategic climate change adaptation – The case of Queenstown-Lake Wanaka,New Zealand

Weather conditions that influence natural resource-based tourist destinations are likely to be affected by climate change, but our understanding of how businesses and destinations manage for present and future conditions is limited. In this study we report on the relationships between weather and tourism activities in the Queenstown-Lake Wanaka region, South Island, New Zealand. Key stakeholder interviews and a workshop form the empirical basis of this paper. Coping range application ideas derived from ecological management literature are used to develop a framework to understand and inform thinking and strategies around how tourism businesses and destinations are currently responding to the weather and perhaps could in future respond to climate change. Results show that within a destination individual businesses have widely varying relationships with the weather, with each type of activity operating within its own coping range to particular environmental gradients, for example temperature. Coping, which can be observed outside the ‘ideal’ range of a particular environmental gradient, requires business adjustments so as to cope with increasingly marginal conditions, up to a Critical Stop Point – the ultimate threshold. The data suggest that increased need for adjustments impacts on business viability, and more planned adaptation measures would be necessary to increase viability under increasingly detrimental climatic conditions. Discussion at a destination level workshop indicates that at and beyond thresholds, keystone industry and destination level strategic adaptation planning is required to ensure the viability of the destination as a whole.