ENSO-Flavor Differences in Indonesian Marine Heatwaves: Satellite SST, Physical Covariates, and Coral Habitat Suitability

Abstract

Marine heatwaves (MHWs) in the Indonesian Seas develop within a long-term rise in sea surface temperature and strong interannual climate variability. We analyze daily NOAA Optimum Interpolation Sea Surface Temperature version 2.1 for 1982–2022 and compare five Eastern-Pacific (EP) with five Central-Pacific (CP) El Niño events. MHWs are detected against a fixed 1982–2011 baseline, and each event is represented by the common 1 July–30 June window spanning its developing and decaying phases. EP-minus-CP differences are 14.25 area-weighted MHW days and 22.34 °C·days of cumulative intensity. Their event-bootstrap intervals span zero, the exact permutation tests are nonsignificant, and no grid cell passes false-discovery-rate control for either metric. Annual MHW days increase by an area-weighted 11.37 days per decade; 90.5% of the domain passes false-discovery-rate control, and the temporal-block field test yields p=0.001. The increase remains widespread after linear Niño-3.4 and dipole-mode-index adjustment. Direct physical diagnostics, spatial-block habitat validation, and official Fisheries Management Area (FMA) summaries are used to assess the strength and limitations of the proposed process and management interpretations. The physical-diagnostic intervals include zero, and the MaxEnt output represents modeled environmental suitability. The results establish a spatially extensive long-term increase in MHW exposure and quantify the uncertainty in the event-scale physical and ecological pathways.