Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Department of Land Surveying and Geo-Informatics | en_US |
| dc.contributor.advisor | Wang, Shuo (LSGI) | en_US |
| dc.creator | Zhou, Mo | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/14749 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | Coastal hydrometeorological extremes in a warming climate | en_US |
| dcterms.abstract | Global warming is reshaping the climate system by intensifying tropical cyclones, increasing heat extremes, and worsening coastal hazards through sea-level rise. It also affects coastal compound events, such as concurrent heatwaves and extreme sea levels, by altering their frequency, duration, intensity, and lag dependence. These evolving hazards have already caused substantial socio-economic and environmental impacts, highlighting the need for improved prediction, risk assessment, and disaster preparedness. | en_US |
| dcterms.abstract | Although research on coastal extremes and compound events has expanded, understanding of their dynamic evolution and underlying physical mechanisms remains limited. To address this gap, this dissertation investigates the evolution, mechanisms, and interactions of coastal extremes. First, I developed an integrated framework combining a wind-pressure model, a hydrodynamic model, and a depth-damage function to assess tropical cyclone-induced coastal flood hazards in Hong Kong. Building on this, I examined compound heatwaves and extreme sea levels, including both concurrent and consecutive events, and finally analyzed the global lag dependence between heatwaves and tropical cyclones. The main findings are as follows. | en_US |
| dcterms.abstract | (1) The northwestern region of Hong Kong is the most vulnerable to coastal flooding. In the case of Typhoon Hato (2017), the effects of extreme high tide and sea-level rise are comparable in their contribution to coastal flooding. In contrast, for Typhoon Mangkhut (2018) and Typhoon Saola (2023), extreme high tide has a more pronounced impact on exacerbating flooding. The worst-case scenario, combining extreme tides with sea level rise under SSP585, could amplify economic losses by 1.2–1.5, 1.7–1.9, and 2.0–2.3 times for the three typhoons. Residential areas are particularly vulnerable, with economic losses five times higher than commercial buildings and double those of industrial buildings. | en_US |
| dcterms.abstract | (2) Along Europe’s coastline, nearly half of the coastal areas have experienced an increase in the frequency of consecutive heatwaves and extreme sea levels in recent years, with an average rate of 0.4 events per decade. Heatwaves followed by extreme sea levels exhibit an average air temperature that is 0.3°C higher than heatwaves not followed by extreme sea levels. By mid-century, under a high-emission scenario, the frequency of such consecutive extreme events is projected to increase eightfold compared to that during the historical period, primarily due to the rising frequency of heatwaves. | en_US |
| dcterms.abstract | (3) 88% of global coastlines have experienced concurrent heatwaves and extreme sea levels during 1979−2017. There is an average increase of 3.7 days in the occurrence during 1998–2017 compared to 1979–1998. A one-percentile increase in heatwave intensity is associated with a 2% increase in the likelihood of concurrent extremes. Global coastlines are projected to experience 38 days of concurrent extremes each year during 2025–2049 under the highest emission scenario. The weakening of geopotential height associated with a surface low-pressure system may serve as an important indicator for the occurrence of extreme sea levels during heatwaves. | en_US |
| dcterms.abstract | (4) Overall, 31% of tropical cyclones are preceded by heatwaves, with East Asia showing the shortest average time lag of 3.2 days. From 1981 to 2022, the time lag between preceding heatwaves and subsequent tropical cyclones shortened by 16% (approximately 0.8 days). Heatwaves preceding tropical cyclones are generally shorter but more intense, likely fueled by heat and moisture associated with approaching tropical cyclones. In addition, faster tropical cyclone translation speeds may be a key driver of the recent shortening of the time lag, particularly for the shortest-lag events (time lag = 1 day), with an attributable fraction of 10.8% (95% CI: 8.8%–13.0%). | en_US |
| dcterms.abstract | The findings of this dissertation reveal that coastal extremes and coastal compound events have intensified over recent decades, posing serious challenges to the adaptive capacity of both ecosystems and human societies under global warming. The simulation and estimation of coastal flood losses advance existing methodologies in flood risk assessment and highlight the critical importance of addressing flood risks in coastal cities. Investigations into compound heatwaves occurring alongside extreme sea levels and tropical cyclones provide valuable insights for mitigating the cascading impacts of both consecutive and concurrent extreme events. The findings emphasize the importance of adopting integrated and cross-sectoral approaches to manage interrelated vulnerabilities and build resilience, particularly in areas most affected by compound hydrometeorological events. | en_US |
| dcterms.extent | 174 pages : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2026 | en_US |
| dcterms.educationalLevel | Ph.D. | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.accessRights | open access | en_US |
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