The very strong coastal El Niño in 1925 in the far-eastern Pacific

Abstract

dynamics associated with the ITCZs, northerly winds, and the north-south SST asymmetry in the FEP lead to the enhancement of the seasonal cycle that produced this EN event. We propose that the cold conditions in the westerncentral equatorial Pacific, through its teleconnection effects on the FEP, helped destabilize the ITCZ and enhanced the meridional ocean-atmosphere feedback, as well as helping produce the very strong coastal rainfall. This is indicated by the nonlinear relation between the Piura river record at 5°S and the SST difference between the FEP and the westerncentral equatorial Pacific, a stability proxy. In summary, there are two types of EN events with very strong impacts in the FEP, both apparently associated with nonlinear convective feedbacks but with very different dynamics: the very strong warm ENSO events like 1982ENSO events like -1983ENSO events like and 1997ENSO events like -1998, and the very strong "coastal" EN events like 1925.

A plausible atmospheric trigger for the 2017 coastal El Niño

“…Local ocean–atmosphere feedbacks may amplify this initial wind/SST perturbation (e.g. Takahashi and Martínez, ). Probing the mechanisms suggested here offers an opportunity to understand coastal El Niño and, hence, contribute to preparedness efforts to face strong events in the future.…”

Rainfall along the coast of Peru during strong El Niño events

“…Local processes of air–sea interactions are also thought to be at work during El Niño events in this region (B. Dewitte, 2017; personal communication). While local SST anomalies are not likely to be the only factor influencing the rainfall conditions during strong El Niño events (Takahashi and Martinez, ), our study calls for investigating the sensitivity of the rainfall distribution and evolution to the regional oceanic conditions, which could be through the use of a regional atmospheric model. This is planned for future work.…”

“…The atmospheric ENSO teleconnections have been extensively studied as they can provide a mechanism by which the main mode of interannual variability in the tropics, that is ENSO, can impact regional climate over the globe. For the coast of Peru where dry mean conditions usually prevail south of 7°S, these are particularly spectacular during strong El Niño events, because the coastal region experiences heavy rainfall as far south as the Lima region (Takahashi and Martinez, ). Second, ENSO is associated with planetary oceanic wave activity along the equator (i.e.…”

Understanding the El Niño Costero of 2017: The Definition Problem and Challenges of Climate Forecasting and Disaster Responses

“…Preliminary scientific literature in Peru suggests El Niño costero is not a new type, but rather it is a different kind of El Niño such as the one documented in 1925 (Takahashi and Martínez 2017), which Peruvians remember as a disastrous event of great magnitude on their northern coast (Murphy 1926;Cordova Aguilar 1996). El Niño costero's evolution and impacts are still under investigation.…”