17:15 〜 19:15
[AOS19-P05] Projection of Extreme Total Water Levels in Southeast Asia Considering Climate Change and Natural Variability
キーワード：Extreme Total Water Level, Climate Change, Southeast Asia
Southeast Asia is most vulnerable to extreme sea level events due to its dense coastal populations and low-lying topography. Sea level rise (SLR) further exacerbates the risk and is expected to accelerate in the future, potentially doubling the frequency of coastal flooding events. Previous studies have conducted the projection of extreme sea levels. However, these studies only accounted for changes driven by the rise of sea level (SLR) and assumed other components of sea level remained unchanged. This study aims to address this limitation by incorporating projected changes in other components of sea level, considering sea level anomaly (SLA), storm surge (SS), wave, tide, and mean sea level (MSL). We present changes in Extreme Total Water Level (TWL) until 2099 under the SSP5-8.5 scenario. Additionally, we utilized the coastal slope calculated from ALOS AW3D30 to improve the wave setup estimations. A non-stationary Generalized Extreme Value (GEV) model was applied to each component independently to account for the non-stationary extreme behavior and capture the evolving risk of extreme sea-level events. The results indicate that TWL in the equatorial zone tends to be smaller than in higher and lower latitude regions due to its limited water level variability. However, the projected changes in TWL indicate a similar rate of increase across all regions, implying that equatorial areas will face a more severe impact from climate change. Between 2000 and 2099, we project an average increase in the 20-year TWL return period of 50-90 cm, driven primarily by SLR. On the other hand, SS components and wave setup decrease 10-15 cm and 30-50 cm, respectively, in higher latitudes. Furthermore, a wave setup decrease of 10-30 cm is observed in lower latitudes, while middle latitudes show a slight increase of 5-10 cm.