Tropical Atmospheric Intraseasonal Oscillations Leading to Sea Level Extremes in Coastal Indonesia during Recent Decades

• DOI: 10.1175/jcli-d-23-0374.1
• Publication Date: 2024-03-06T14:02:21Z
• Authors: William Kamp; Weiqing Han; Lei Zhang; Shoichiro Kido; Julian P. McCreary
• Keywords: Madden–Julian oscillation; Atmospheric Circulation

Abstract Coastal flooding induced by sea surface high extreme (HEX) events is an increasing risk to human society and infrastructure as both urban growth in coastal areas anthropogenic level rise continue, especially for island nations like Indonesia. This paper investigates the role of atmospheric intraseasonal oscillations (ISOs), which are dominated Madden–Julian oscillation (MJO), forcing HEXs on coasts Indonesia bordering Indian Ocean. We use satellite altimetry data from 1993 2021 tide gauge observations detect HEXs, modeling experiments using Regional Ocean Modeling System a Bayesian dynamic linear model understand processes. find that exhibit strong seasonality, with most occurring during boreal winter (December–February) spring (March–May) seasonal-to-decadal variability respectively. In 32% 56 HEX detected, amplitude ISO-induced anomalies (SLAs) exceeds SLAs. Surface wind stress associated ISOs major SLAs, remote westerly equator northwesterly longshore at Indonesian play important roles driving HEXs. The MJO dominant cause ISO-dominated its impact shows seasonal differences. Spring MJOs stronger convective over eastern drive zonal winds across equatorial basin lead more compared when convection shifted southward.