Hydroclimatic variability in Santiago (Chile) since the 16th century

35 Pags.- 7 Figs.- 4 Tabls. The definitive version is available at: https://rmets.onlinelibrary.wiley.com/journal/10970088The long‐term hydroclimatic variability in Santiago (Chile) was analysed by means of a new 481‐year (1536–2016 CE) tree‐ring reconstruction of the Standardized Precipitation Evapotranspiration Index (SPEI) of August, integrating the hydroclimatic conditions during the preceding 14 months. Results show a high frequency of extreme drought events in the late 20th and early 21st centuries, while the frequency of extreme wet events was higher in the 17th–18th centuries. The mid‐20th century represents a breaking point for the hydroclimatic history in the region, including some significant changes: (a) the interannual variability increased; (b) the wet events became less intense; (c) the extreme dry events became more frequent; and (d) the most intense dry event of the entire period was identified, coinciding with the so‐called Megadrought (2006–2016). A correlation analysis between the reconstructed SPEI and three climate indices (PDO, SOI and Niño3.4) was performed at monthly scale, considering different multi‐annual aggregations. The analysis shows diverse impacts on the hydroclimatic variability, with positive correlations between SPEI and PDO as well as Niño3.4, and negative correlations between SPEI and SOI. The most significant correlations were, overall, found at multi‐annual time scales (>7 years). Results help to better understand the current hydroclimatic changes (Megadrought) in a long‐term context.R.S.N. is funded by a “Juan de la Cierva” postdoctoral grant FJCI-2017-31595. This work was developed under the project CAS/1900020 funded by the Spanish Ministry of Science and the Fulbright Foundation. O.M.R., P.S. and R.S.N. thank the Climatology Group (2017SGR1362, Catalan Government) and the CLICES Project (CGL2017-83866-C3-2-R). R.S.N. and M.D.L. are supported by the Government of Aragón through the “Programme of research groups” (group H38, “Clima, Agua, Cambio Global y Sistemas Naturales”) and thank the project CGL2015-69985-R. E.T. and M.V. were partially supported by NSF-PIRE (OISE-1743738) and NSF-P2C2 (AGS-1702439). M.F. is funded by a postdoctoral grant CONICYT PIA AFB170008 of the Institute of Ecology and Biodiversity (IEB).Peer reviewe