Improving typhoon storm surge disaster prevention and mitigation capacity: a spatiotemporal analysis of occurrence probability and impact in China

The compound typhoon storm surge disaster (CTSSD) is a major marine disaster in China. Investigating its spatiotemporal characteristics is crucial for enhancing prevention and mitigation. Characterized by a large spatial scale (China) and a long time series (1989–2020), this paper proposes a framework to investigate the occurrence probability and impact under different CTSSD scenarios. The framework contains two dimensions, time and space, and methods such as the Mann-Kendall test, the Standard Deviation Ellipse model and the Spatial clustering analysis are adopted. Furthermore, the links between observed characteristics with policy, adaptation and geography are explored, to propose suitable risk governance recommendations for Chinese CTSSD. The results show that the spatiotemporal characteristics of occurrence probability under different CTSSD scenarios are different, which are closely related to the uneven spatiotemporal distribution of precipitation, typhoon landings and the tide range of astronomical tide. Consequently, a regionalized strategy of “wind and precipitation prevention in South China, and astronomical tide prevention in North China” is proposed. The occurrence probability shows an increasing trend but the impact shows a downward trend, suggesting that policies taken by China (such as building high-standard seawalls, developing technology, and institutional construction) reduce the damage of CTSSD effectively. Drawing on international experiences, a suggestion of “establish a long-term and flexible CTSSD management strategy, use both ‘soft’ measures and ‘hard’ measures, develop community-based CTSSD management” is put forward, aiming to offer innovative insights for CTSSD prevention and management in China.