Multi-scale features of the co-variability between global sea surface temperature anomalies and daily extreme rainfall in Argentina

ROBLEDO F., VERA C., PENALBA O.

INTERNATIONAL JOURNAL OF CLIMATOLOGY

JOHN WILEY & SONS LTD

Lugar: LOndres; Año: 2020

0899-8418

The goal of this study is to provide a better understanding of the trends anddominant oscillations characterizing the co-variability between global sea surfacetemperature (SST) anomalies and daily extreme rainfall in Argentina. Asingular value decomposition was performed between daily extreme rainfallmonthly index in Argentina and global SST without removing the trends. Thethree leading modes explain 70.5% of the co-variability, while the two leadingmodes explain more than 66% of the variability. The two leading modes exhibitsignificant variability on inter-annual timescales related to tropical Pacific andIndian oceans, and specifically with El Niño? Southern Oscillation and theIndian Ocean Dipole. On decadal timescales, the leading mode activity isrelated to the Pacific Decadal Oscillation, whereas the second leading mode isassociated with the Atlantic Multi-decadal Oscillation (AMO). The third leadingmode show co-variability between the SST of the tropical Atlantic and theIndian ocean and extreme rainfall in the eastern-centre of Argentina; thismode distinguishes phases of AMO. In addition, the two leading modes showpositive trends, being largely non-linear for leading one. The fact that extremerainfall changes in Argentina observed in the last decades, are significantlyinfluenced by the combination of the multi-decadal variability and long-termtrends associated with the tropical oceans, is valuable knowledge to assessthem in the future.