Tarawa is a low-lying atoll in the Gilbert Island group, capital of the Republic of Kiribati and home of nearly 70.000 inhabitants. With limited land area, rapid population growth and urbanization, strong interannual sea level variability induced by ENSO and sea level rise, Tarawa is highly vulnerable to coastal flooding. In this context, Early Warning Systems are a proven cost-effective climate adaptation measure to strengthen community resilience. In virtually enclosed atolls, the water level experienced at the shore is compounded by tides, sea level anomaly, storm surge and the contribution of waves. While wave setup and runup, are the primary components driving inundation along the ocean-facing shorelines, sea level anomaly, wind setup and wave pumping through the atoll rim contributes more inside lagoons. In this paper we present an efficient process-based approach to forecast flooding events along both, the ocean and lagoon coasts of atoll islands. With the intention of being highly scalable to other island countries, the system has been designed as a lightweight and accurate tool, that provides actionable and user-friendly water level predictions 7 days in advance. Publicly available global forecast products are ingested by a high-resolution wave model and tailor-made metamodels to translate ocean forcings to water levels at the shore. In absence of a comprehensive topography dataset, extreme value distributions of 27-year hourly water levels were evaluated every 500 m along the coast to define and communicate different levels of warnings according to the recurrence interval of the forecasted event. The long-term wave climate, nearshore wave transformation, and water levels produced under this work increase Tarawa's risk knowledge and support informed investments and future development strategies. While this system will significantly enhance ocean services in Kiribati, improving baseline data still remains a critical need for government and communities to support informed decision making to better cope with increased coastal hazards.

塔拉瓦是吉尔伯特岛群中的一个低洼环礁，是基里巴斯共和国的首都，拥有近 70,000 名居民。由于土地面积有限、人口快速增长和城市化、ENSO 和海平面上升引起的海平面年际变化剧烈，塔拉瓦极易遭受沿海洪水的影响。在这种情况下，早期预警系统是一种经证明具有成本效益的气候适应措施，可以增强社区的抵御能力。在几乎封闭的环礁中，海岸的水位因潮汐、海平面异常、风暴潮和波浪的影响而加剧。虽然波浪的建立和上升是驱动面向海洋的海岸线淹没的主要因素，但海平面异常、风的建立和通过环礁边缘的波浪泵送对泻湖内部的影响更大。在本文中，我们提出了一种基于流程的有效方法来预测环礁岛屿海洋和泻湖沿岸的洪水事件。为了能够高度扩展到其他岛国，该系统被设计为一种轻量级且准确的工具，可以提前 7 天提供可操作且用户友好的水位预测。公开的全球预报产品由高分辨率波浪模型和定制元模型吸收，将海洋强迫转换为岸边的水位。在缺乏全面地形数据集的情况下，沿海岸每 500 m 评估 27 年每小时水位的极值分布，以根据预报事件的重复间隔定义和传达不同级别的警报。这项工作产生的长期波浪气候、近岸波浪转变和水位增加了塔拉瓦岛的风险知识，并支持明智的投资和未来的发展战略。虽然该系统将显着增强基里巴斯的海洋服务，但改善基线数据仍然是政府和社区支持明智决策以更好应对日益增加的沿海灾害的迫切需要。