Low‐frequency modulation and trend of the relationship between ENSO and precipitation along the northern to centre Peruvian Pacific coast

Abstract

Abstract:The relationship between El Niño Southern Oscillation (ENSO) and precipitation along the Peruvian Pacific coast is investigated over 1964-2011 on the basis of a variety of indices accounting for the different types of El Niño events and atmospheric and oceanographic manifestations of the interannual variability in the tropical Pacific. We show the existence of fluctuations in the ENSO/precipitation relationship at decadal timescales that are associated with the ENSO property changes over the recent decades. Several indices are considered in order to discriminate the influence of the two types of El Niño, namely, the eastern Pacific El Niño and the central Pacific El Niño, as well as the influence of large-scale atmospheric variability associated to the Madden and Julian Oscillation, and of regional oceanic conditions. Three main periods are identified that correspond to the interleave periods between the main climatic transitions over 1964-2011, i.e. the shifts of the 1970s and the 2000s, over which ENSO experiences significant changes in its characteristics. We show that the relationship between ENSO and precipitation along the western coast of Peru has experienced significant decadal change. Whereas El Niño events before 2000 lead to increased precipitation, in the 2000s, ENSO is associated to drier conditions. This is due to the change in the main ENSO pattern after 2000 that is associated to cooler oceanic conditions off Peru during warm events (i.e. central Pacific El Niño). Our analysis also indicates that the two extreme El Niño events of 1982/1983 and 1997/1998 have overshadowed actual trends in the relationship between interannual variability in the tropical Pacific and precipitation along the coast of Peru. Overall, our study stresses on the complexity of the hydrological cycle on the western side of the Andes with regard to its relationship with the interannual to decadal variability in the tropical Pacific.

A new assessment in total and extreme rainfall trends over central and southern Peruvian Andes during 1965–2010

“…Our results for regions B and D corroborate to some extent with the results in Bourrel et al . () and Vuille et al . ().…”

“…Bourrel et al . () showed that with exception of the strong 1982/1983 and 1997/1998 ENSO events, the region experienced increased (decreased) rainfall during EN years of the period 1964–1999 (2000–2011).…”

Assessing multidecadal runoff (1970–2010) using regional hydrological modelling under data and water scarcity conditions in Peruvian Pacific catchments

“…A careful quality check of these data was previously performed. Monthly precipitation, temperature, and streamflow data were homogenized and validated according to Bourrel et al (); Rau et al (); Rau et al (). Precipitation and temperature data were interpolated to a 5 × 5 km grid using inverse distance weighting interpolation and considering altitudinal gradients.…”

Monitoring of the Spatio-Temporal Dynamics of the Floods in the Guayas Watershed (Ecuadorian Pacific Coast) Using Global Monitoring ENVISAT ASAR Images and Rainfall Data

“…. A careful quality check of this data was performed using the regional vector method similarly to what was performed in [3,4]. This dataset was interpolated at a spatial resolution of 1 km using a co-kriging method as in [4].…”

“…El Niño Southern Oscillation (ENSO) has a strong influence on rainfall patterns on the Pacific Coast of South America, from Ecuador to Chile, at an interannual time scale e.g., [1][2][3][4], affecting the likelihood of droughts and floods [5]. Positive anomalies of sea surface temperatures along the coast of Peru and Ecuador occurring during ENSO events induced torrential rains that cause high discharge and large flood events [6].…”