The complex behavior of El Niño winter 2015–2016

• Published in: Geophysical Research Letters
• Main Authors: Palmeiro, Froila M., Iza, M., Barriopedro, David, Calvo, N., García Herrera, Ricardo
• Other Authors: Ministerio de Economía y Competitividad (España), European Commission
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2017
• Subjects: Stratosphere; ENSO; SSW; Coupling; Studycase; SST; Greenland; Midwinter; Pacific; aleutian low
• Online Access: http://hdl.handle.net/10261/185341; https://doi.org/10.1002/2017GL072920; https://doi.org/10.13039/501100003329; https://doi.org/10.13039/501100000780

This paper examines the outstanding characteristics of the strong 2015–2016 El Niño (EN) winter and its impact over the European region through the stratosphere. Despite being classified as a strong eastern Pacific (EP) EN event, our analysis reveals an anomalous behavior, with some signatures that are more typical of central Pacific (CP) EN events instead. They include (i) a record‐breaking value of the CP index, (ii) a stronger polar vortex in early and midwinter, due to reduced upward wave activity and a weakened Aleutian low, and (iii) the occurrence of one of the earliest stratospheric final warmings (SFWs) on record, which are more prone to occur during CP‐EN. Following the SFW, a stratospheric influence on the Euro‐Atlantic sector is reported in spring, with persistent Greenland blocking resulting in extreme precipitation over some southern European regions. Results highlight the importance of considering early SFWs as mediators of El Niño teleconnections. This work wassupported by the Spanish Ministry ofEconomy and Competitivenessthrough the PALEOSTRAT (CGL2015-69699-R) project and the EuropeanProject 603557-STRATOCLIM underprogram FP7-ENV.2013.6.1-2. F.M.Palmeiro was funded by grantBES-2013-063906. Peer reviewed