Assessing the impact of El Niño Modoki on seasonal precipitation in Colombia Samir Córdoba-Machado a,b , Reiner Palomino-Lemus a,b , Sonia Raquel Gámiz-Fortis a , Yolanda Castro-Díez a , María Jesús Esteban-Parra a, ⁎ a Applied Physics Department, University of Granada, Granada, Spain b Technological University of Chocó, Colombia abstract article info Article history: Received 30 May 2014 Received in revised form 13 November 2014 Accepted 14 November 2014 Available online 20 November 2014 Keywords: Seasonal precipitation Tropical Pacific SST El Niño El Niño Modoki Singular value decomposition Colombia The influence of the tropical Pacific SST on precipitation in Colombia is examined using a 341 station dataset covering the period 1979–2009. Through a singular value decomposition the two main coupled variability modes show SST patterns clearly associated with canonical El Niño and El Niño Modoki, respectively, presenting great coupling strength with the corresponding seasonal precipitation modes in Colombia. The results reveal that, mainly in winter and summer, canonical El Niño and El Niño Modoki events are associated with a significant rainfall decrease over the northern, central, and western Colombia. The opposite effect occurs in some localities during spring, summer, and autumn. The southwestern region of Colombia exhibits an opposite behavior con- nected to canonical El Niño and El Niño Modoki events during years when both events do not coexist, showing different seasonal precipitation response to these different patterns. The results found establish the foundations for precipitation modeling in Colombia from the Pacific SST. © 2014 Elsevier B.V. All rights reserved. 1. Introduction The most important phenomenon of ocean–atmosphere coupling over tropical Pacific Ocean is known as El Niño Southern Oscillation (ENSO), El Niño of Eastern Pacific (Eastern Pacific, EP) or the canonical El Niño (ENC), which shows a pattern of positive sea surface tempera- ture (SST) anomalies (anomalous warming) over the east tropical Pacific and negative SST anomalies (anomalous cooling) in the west (e.g. Rasmusson and Carpenter, 1982). Numerous studies have focused on trying to understand and predict the climatic impact of SST associat- ed with El Niño (e.g. Rasmusson and Carpenter, 1982; Ropelewski and Halpert, 1987; Trenberth and Hoar, 1996; Trenberth, 1997; Neelin et al., 1998, 2000; Wallace et al., 1998; Chan and Xu, 2000; Fasullo and Webster, 2000; White and Cayan, 2000; Trenberth and Stepaniak, 2001; Trenberth et al., 2002; Larkin and Harrison, 2005; Coulibaly, 2006; Omondi et al., 2013), identifying its influence on many parts of the world through the representation of the phenomenon by several indices (El Niño indices: 3, 4, 3.4, 1 + 2). However, the interpretation of the spatial pattern of the tropical Pacific SST has evolved to the point of identifying a new type of El Niño, called El Niño Modoki, Central Pacific El Niño (Central Pacific, CP), or Pseudo Niño (Ashok et al., 2007; Weng et al., 2007). Ashok et al. (2007) proposed the term El Niño Modoki (ENM) to identify the phenomenon of ocean–atmosphere coupling that records SST positive anomalies (warm) in the central tropical Pacific and SST negative anomalies (cold) in the eastern and western tropical Pacific. In addition, the El Niño Modoki index (EMI) was constructed to quantify the phenomenon of ENM and demonstrate that this phenomenon presents different spatial and temporal characteristics to ENC event. The EMI index captures the SST zonal gradient in the eastern and west- ern tropical Pacific. Several authors describe these two types of Niño in different ways (Trenberth et al., 2002; Larkin and Harrison, 2005; Ashok et al., 2007; Weng et al., 2007; Yu and Kao, 2007; Hill et al., 2009; Kao and Yu, 2009; Kug et al., 2009), but all show that warming in the central Pacific is a different phenomenon from warming over the eastern trop- ical Pacific. Several recent studies have shown that El Niño Modoki has become more frequent during the last three decades, whereas the ca- nonical El Niño has occurred less frequently (Lee and McPhaden, 2010; Choi et al., 2012). The differences found between ENC and ENM regarding their teleconnection patterns and climatic impacts, imply that these two phenomena can be studied separately (Ashok et al., 2007, 2009; Weng et al., 2007, 2009, 2011; Wang and Hendon, 2007; Chang et al., 2008; Taschetto and England, 2009; Taschetto et al., 2009; Kim et al., 2009, 2011; Tedeschi et al., 2013). Some studies use the index of the El Niño 3.4 region (Trenberth, 1997), to analyze the influence of ENC. However, Global and Planetary Change 124 (2015) 41–61 ⁎ Corresponding author at: Departamento de Física Aplicada, Facultad de Ciencias, Universidad de Granada, Campus Fuentenueva s/n, 18071-Granada, Spain. Tel.: +34 958 240021; fax: +34 958 243214. E-mail address: esteban@ugr.es (M.J. Esteban-Parra). http://dx.doi.org/10.1016/j.gloplacha.2014.11.003 0921-8181/© 2014 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Global and Planetary Change journal homepage: www.elsevier.com/locate/gloplacha