Abstract
In 2017, extreme rainfall events occurred in the northern portion of Peru, causing nearly 100,000 victims, according to the National Emergency Operations Center (COEN). This climatic event was attributed to the occurrence of the El Niño Southern Oscillation (ENSO). Therefore, the main objective of this study was to determine and differentiate between the occurrence of canonical ENSO, with a new type of ENSO called “El Niño Costero” (Coastal El Niño). The polynomial equation method was used to analyze the data from the different types of existing ocean indices to determine the occurrence of ENSO. It was observed that the anomalies of sea surface temperature (SST) 2.5 °C (January 2016) generated the “Modoki El Niño” and that the anomaly of SST −0.3 °C (January 2017) generated the “Modoki La Niña”; this sequential generation generated El Niño Costero. This new knowledge about the sui generis origin of El Niño Costero, based on the observations of this analysis, will allow us to identify and obtain important information regarding the occurrence of this event. A new oceanic index called the Pacific Regional Equatorial Index (PREI) was proposed to follow the periodic evolution and forecast with greater precision a new catastrophic event related to the occurrence of El Niño Costero and to implement prevention programs.
Highlights
El Niño Southern Oscillation (ENSO) events are one of the most important sources of annual climate variability
Same central Equatorial zone of the Pacific Ocean clearly defines the presence of Modoki (Figure 3). This large-scale oscillation from warmer to colder sea surface temperature (SST) and in the ENSO and Modoki LNSO, whose process and sequence will serve to define the pressame central Equatorial zone of the Pacific Ocean clearly defines the presence of Modoki ence of coastal ENSO
According to the analysis carried out, we propose that the presence of coastal ENSO in the Inter-Tropical Convergence Zone (ITCZ) would have generated areas of low pressure, favoring the formation and rise of large masses of humid air, turning into extensive clouds that produced the heavy rainfall in the central and northern areas of Peru
Summary
El Niño Southern Oscillation (ENSO) events are one of the most important sources of annual climate variability. These phenomena involve large-scale interactions between the oceans and the atmosphere, which consist of an oscillation of atmospheric pressure in the western Pacific [1]. The occurrence of ENSO in the tropical Pacific causes a variation on the oceanic-atmospheric systems in both the North Pacific and the North Atlantic [3]. ENSO is considered the most powerful signal in terms of the interannual variation of the oceanic-atmospheric system [4]. Records indicate that the occurrence of ENSO in South America has shown statistically significant evidence since 1750. From the 18th century onwards the chronology of ENSO and anti-ENSO events have occurred with similar chronologies in the literature [5]
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