The Trend and Interannual Variability of Marine Heatwaves over the Bay of Bengal

Marine heatwaves (MHWs) are long-lasting extreme oceanic warming events that can cause devastating effects on warm-water corals and associated ecosystems. The linear trend interannual variability of MHWs over the Bay Bengal (BOB) during 1982–2020 investigated by a high-resolution daily sea surface temperature (SST) dataset. In regions where coral reefs concentrated, annual MHW days frequency significantly increase 1982–2020, at rates exceeding global mean. coldest boreal winter season witnesses significant steady trends in frequency. contrast, is insignificant climatological warmest (March to June) south 15° N BOB, mainly due large variability. El Niño Southern Oscillation (ENSO) dominates BOB MHWs, which highly consistent with evolution mean SST. negative phase North Atlantic (NAO) also modulates occurrences especially northeastern BOB. two climate modes synergistically explain about 50~70% variances BOB’s MHWs. Correlation analysis reveals effect evident from autumn its developing summer decaying phase, along limited influence NAO. However, northeast merely emerges April August stage. comparison, winter-to-spring NAO exerts strong control March-to-June results suggest various may jointly or separately certain seasons locations, important for seasonal prediction Indeed, when combining Niño3.4 mature index build regression model, it more effective reproducing compared alone.