Seasonal precipitation in South Central Chile: trends in extreme events since 1900

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Álvaro González-Reyes
https://orcid.org/0000-0001-7525-349X
Martin Jacques-Coper
https://orcid.org/0000-0002-8841-3699
Ariel Andres Muñoz

Abstract

We study a regional precipitation time series, built upon seven meteorological records from South Central Chile (SCC; 37° - 42°S), which together cover the period 1900 - 2019. As a first objective, we investigated changes in the return period (RP) of dry (<P20) and wet (> P80) seasonal extreme events of precipitation (SEE), for each season. We observed a reduction in the RP of wet SEE during 1900 - 1950 in all seasons. Contrarily, the dry SEE RP shows a reduction from 1950 to the present in all seasons. This phenomenon is noteworthy since 1900 for summer and winter, and since 1930 for autumn. Spring registers a constant RP value from 1990 onwards. As a second objective, we study possible relationships between seasonal precipitation variability and climate modes, such as the Southern Annular Mode (SAM) and the Tripolar Index (TPI) of sea surface temperature (SST) over the Pacific Ocean. Summer and autumn precipitation register a significant negative correlation with SAM activity at interannual and decadal scales, while winter and spring precipitation show a significant positive correlation with SST variability over multiple regions of the Pacific Ocean (including the tropics and New Zealand) and the Southern Ocean (Amundsen-Bellingshausen Sea). Finally, we confirm that SAM strongly modulates precipitation in SCC, especially in autumn, and that SEE variability in SCC is considerably characterized by climate modes of tropical and extra-tropical origin.

 

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Author Biographies

Álvaro González-Reyes, Hémera, Centro de Observación de la Tierra. Universidad Mayor, Camino La Pirámide 5750, Huechuraba, Santiago 8580745, Chile . Center for Climate and Resilience Research (CR)2, Chile.

Hémera, Centro de Observación de la Tierra.

Martin Jacques-Coper, Departamento de Geofísica, Universidad de Concepción, Concepción, Chile. Center for Climate and Resilience Research (CR)2, Chile.

Departamento de Geofísica, Universidad de Concepción, Concepción, Chile.

Ariel Andres Muñoz, Pontificia Universidad Católica de Valparaíso , Instituto de Geografía, Facultad de Ciencias del Mar y Geografía, Valparaíso, Chile. Center for Climate and Resilience Research (CR)2, Chile.

Instituto de Geografía, Facultad  de Ciencias del Mar y Geografía.

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