Combination of atmospheric and oceanic processes induced long lasting marine heatwave in the Southeast Pacific Ocean

Marine heatwaves (MHWs) are discrete warm-water anomalies events occurring in every ocean around the globe, in both coastal and open ocean, having major impacts on ecosystems, fisheries and aquaculture. They are generally caused by a combination of oceanic and atmospheric conditions that favours the increase of the sea surface temperature and/or reduce the heat transfer from the ocean to the atmosphere. Here we investigated through satellite data the formation of a MHW offshore the Chilean Patagonia in the Southeast Pacific Ocean which lasted from May to October 2016. That MHW was identifiable through the presence of unusually low heat transfer from the ocean to the atmosphere. This lower than usual heat loss from the ocean was due to the temporary reduction of the wind speed, causing reduced oceanic latent heat loss. These factors, added to the advection of anomalously warm waters from the extratropical South Pacific, favoured the development of a long-lasting MHW.