Seasonal surge extremes in the Indo-Pacific are driven by climate modes, with in-phase ENSO events causing strongest impacts.
Authors
Kamlesh Kumar Saha, Department of Applied Sciences, National Institute of Technology Delhi, Delhi, 110036, India
Prashant Kumar, Department of Applied Sciences, National Institute of Technology Delhi, Delhi, 110036, India
Anurag Singh, Department of Computer Sciences and Engineering, National Institute of Technology Delhi, Delhi, 110036, India
Bahareh Kamranzad, Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow, G11XJ, United Kingdom
T.M. Balakrishnan Nair, Indian National Centre for Ocean Information Services (INCOIS), Hyderabad, India
Rajni, Associate Professor, Jindal Global Business School, O.P. Jindal Global University, Sonipat, Haryana, India
Summary
Extreme storm surges severely affect densely populated coasts and offshore islands across the Indo-Pacific. These extremes are strongly modulated by major climate variability modes, including the El Niño–Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), Pacific Decadal Oscillation (PDO), Pacific–North American (PNA), Northern Annular Mode (NAM), and Southern Annular Mode (SAM) patterns. This study examines their seasonal influence on extreme storm surges during 1979–2018 using GTSM/ERA5 reanalysis data and Generalized Extreme Value (GEV) analysis based on block maxima. ENSO|PDO intensifies extreme surges over the western and eastern Pacific throughout the year, with pronounced enhancement during boreal summer (JJA), while suppressing surge intensity along the Indonesian coast. The IOD exerts significant control over the northern Pacific and southern Australia in boreal spring (MAM), and across the Indian Ocean and Pacific sectors in JJA. PDO|ENSO intensifies storm surge over the North and western Pacific during SON. The PNA notably affects the Gulf of Thailand, Gulf of Carpentaria, and eastern Pacific during boreal winter (DJF), with impacts shifting toward the western North Pacific in JJA. In-phase ENSO–IOD and ENSO–PDO events produce amplified and statistically significant surge extremes, particularly during DJF and JJA.
Published in: Ocean Engineering
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