Physical Sciences and Mathematics Commons^™

Connection Between Spring Conditions And Peak Summer Monsoon Rainfall In South America: Role Of Soil Moisture, Surface Temperature, And Topography In Eastern Brazil, Alice M. Grimm, Jeremy S. Pal, Filippo Giorgi

Civil and Environmental Engineering Faculty Works

A link between peak summer monsoon rainfall in central-east Brazil, composing part of the South American monsoon core region, and antecedent conditions in spring is disclosed. Rainfall in this region during part of spring holds a significant inverse correlation with rainfall in peak summer, especially during ENSO years. A surface–atmosphere feedback hypothesis is proposed to explain this relationship: low spring precipitation leads to low spring soil moisture and high late spring surface temperature; this induces a topographically enhanced low-level anomalous convergence and cyclonic circulation over southeast Brazil that enhances the moisture flux from northern and central South America into central-east …