Lidio López

Tree ring reconstructed rainfall over the southern Amazon Basin

Moisture sensitive tree-ring chronologies of Centrolobium microchaete have been developed from seasonally dry forests in the southern Amazon basin and used to reconstruct wet season rainfall totals from 1799-2012, adding over 150-years of rainfall estimates to the short instrumental record for the region. The reconstruction is correlated with the same atmospheric variables that influence the instrumental measurements of wet season rainfall. Anticyclonic circulation over mid-latitude South America promotes equatorward surges of cold and relatively dry extratropical air that converge with warm moist air to form deep convection and heavy rainfall over this sector of the southern Amazon basin. Interesting droughts and pluvials are reconstructed during the pre-instrumental 19th and early 20th centuries, but the tree-ring reconstruction suggests that the strong multi-decadal variability in instrumental and reconstructed wet season rainfall after 1950 may have been unmatched since 1799.