Disentangling the role of the Pacific and Atlantic Oceans during the Amazonian droughts in 2015

El Niño events lead to worldwide changes in the inter-annual variability of precipitation, and more in particular to South America droughts. In the year 2015, El Niño leads to extremely dry conditions over the Amazon Basin. Based upon climate simulations conducted with the CCM3-IBIS and SPEEDY-Vegas, coupled climate-vegetation models, the impacts of the 2015 Pacific and Atlantic SSTs on drought over the Amazon Basin are investigated. Our results demonstrated that the 2015 El Niño event does not solely is able to explain the reduction in precipitation; however, results show that the anomalous pattern of the Atlantic SST plays the main role in this particular drought event. Distinct results are delivered by the SPEEDY-Vegas, in which the Pacific Ocean plays the leading role in driving the anomalous pattern of precipitation. Dynamically, both models are consistent in providing the climate mechanisms related to the extreme event. Thus, the regional precipitation response is, therefore, tightly linked to the atmospheric model parameterization on its lowest boundary condition, which involves the air-sea interaction. The 2015 drought presented important modifications in the dominant vegetation type over the Amazon Basin. This result indicates the high susceptibility of the Amazon Forest to become savanna-like vegetation if the occurrence of the 2015 SST patterns happens more frequently in the future.