講演情報
[AOS26-P02]Ocean-Atmosphere Forcing of Coastal Ecosystem Stress Across Coral Habitats Along the Western Coast of Aceh
*Faqih Musyaffa1、Po-Chun Hsu1,2 (1.Center for Space and Remote Sensing Research, National Central University, Taiwan、2.Graduate Institute of Hydrological and Oceanic Sciences, National Central University, Taiwan)
キーワード：
Marine heatwaves、Water Quality、Aceh
Coral reef ecosystems along the western coast of Aceh (0-10oN, 90-100oE), located in the eastern tropical Indian Ocean, provide critical coastal ecosystem services yet are increasingly exposed to compounded thermal and water-quality stressors. This study integrates multi-sensor satellite and reanalysis datasets to quantify ocean and atmospheric controls on thermal stress and marine environmental variability under the combined influences of climate change and coastal development. Analyses were conducted at 16 coral habitat sites, grouped into four geographic-oceanographic regions encompassing Weh Island, the western Aceh coastline, the Simeulue Islands, and the Banyak Islands. We combined NOAA Coral Reef Watch satellite-derived sea surface temperature (SST) and Degree Heating Weeks (DHW), ERA5 atmospheric and freshwater flux reanalysis from the ECMWF, CMEMS ocean circulation dataset, and NASA Ocean color products to assess optical water-quality indicators. Results reveal a marked escalation of extreme thermal stress events since approximately 2010, with widespread DHW exceedances across northern and nearshore reef clusters and site-specific transitions to higher coral bleaching alert levels. Five major marine heatwave (MHW) years were identified (2010, 2016, 2019, 2020, and 2024), with extreme DHW values exceeding 4oC-weeks in 2010, 2016, 2019, and 2024, indicating elevated multi-species bleaching and mortality risk. Seasonal monsoon wind reversals reorganize Ekman and geostrophic circulation patterns, producing episodic weak-flushing and onshore convergence regimes that enhance heat retention near reefs and amplify thermal exposure. Monthly SST climatology exhibits seasonal maxima from April to June (~30.5oC) and minima from November to January (~27.5oC). Persistent and seasonally intensified SST frontal structures further delineate coastal-open ocean exchange zones that act as heat-retention and stress hotspots, most pronounced during December-March and June-September. ERA5 net surface heat flux (NSHF) displays a strong seasonal cycle, with positive ocean heat uptake from January to May (~+50 to +100 W m-2), particularly along coast sectors, preconditioning reef environments for subsequent warm-season stress. Freshwater forcing is dominated by precipitation, with evaporation minus precipitation remaining predominantly negative (~0 to -16 mm month-1), indicating net surface freshening from May to December and weaker, near-neutral conditions during January-March. The apparent visible wavelength climatology further reveals systematic seasonal variability, with minimum values in April-May and increasing toward November-January, reflecting seasonal modulation of optical water properties relevant to coral ecosystem exposure during MHW conditions. Overall, this framework provides a physically based foundation for reef resilience assessment, bleaching alert interpretation, and ecosystem-based adaptation planning and monitoring strategies in Aceh waters.