Seasonal, extremes and wave climate variability of the Southwest of Efate Island, Vanuatu

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Wave climate variability is important for assessing coastal hazards and inform coastal planners of coastal adaptations needed. We wrote a paper on wave climate variability in the South West of Vanuatu to improve coastal hazard assessments in this region where monitoring data are often absent.

This paper was peer reviewed and also presented at the Australasian Coasts and Ports Conference in 2019 in Hobart. This conference brings together engineers, scientists, planners, academics and practitioners and stakeholders in the construction industry to focus on the present and future challenges of adapting communities to thrive in dynamic coastal environment.

This paper is an important contribution to a first pass coastal hazard assessment for Mele Bay and Erakor island which is important for coastal planning and to build resilience to extreme events and to future climate change scenarios. In the Small Island Developing States, data monitoring is often limited, and the quality of coastal hazards assessments can be compromised.

When data are missing, global hindcast models can be used for a first assessment of an area. The aim of this paper is to inform the development of resilience to natural hazards through an assessment of the wave climate and do a first assessment of flooding under extreme wave events in two key places, Mele Bay and Erakor Lagoon on Efate Island, Vanuatu.

This approach to wave climate assessment highlights the possibilities for improving the knowledge base for developing resilience to natural hazards despite the data availability constraints typical of SIDSSIDS Small Island Developing States are a distinct group of 38 UN Member States and 20 Non-UN Members/Associate Members of United Nations regional commissions that face unique social, economic and environmental vulnerabilities.. In this paper, wave data from WW3 Global model were analysed to understand the wave climate in the South West of Efate for the last 40-years (from 1979 to 2018). Decadal and seasonal trends are given for the significant wave height, the period, the direction and the wave energy. Potential relationship between climate variability such as El Niño/La Niña events and the wave climate variations is also investigated for future scenarios of impact assessment.

The extreme wave events are defined using the Peaks-Over-Threshold Method. Wave return periods are calculated with three different distributions (Weibull, Gumbel and Log-Normal models). The distribution models are compared in terms of inundation. The variation of wave climate is then discussed as well as the impacts to the shoreline.

Fig: Wave rose at point 1 (lon: 168.1668°; lat:-17.8333°) for the period of 1979-2018. Rose and yellow points are locations of WW3 data available.Red and blue dot represent the localisation of Mele Bay and Erakor Lagoon respectively


Faivre, G., da Silva, G. V., Ware, D., Tomlinson, R., Mackey, B., & Zhang, H. (2019). Seasonal, extremes and wave climate variability of the Southwest of Efate Island, Vanuatu. In: Australasian Coasts and Ports 2019 Conference: Future directions from 40 [degrees] S and beyond, Hobart, 10-13 September 2019. Hobart: Engineers Australia, 2019: 381-387. Engineers Australia.

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