Identifying the Externally Forced Atlantic Multidecadal Variability Signal Through Florida Rainfall

Abstract

The North Atlantic experiences basin-wide, multidecadal changes in sea surface temperature (SST), and this SST variability is linked with regional-to-continental scale impacts. These impacts often serve as motivation to study the underlying contributors to Atlantic Multidecadal Variability (AMV). However, these impacts can be more than motivation—they can be tools to study the AMV itself. Herein, we consider the positive correlation between Florida summertime rainfall and the AMV (Enfield et al., 2001, https://doi.org/10.1029/2000GL012745). First, we show that this relationship is apparent in updated observational data sets. Next, we demonstrate that large ensembles of climate models are capable of producing the observed relationship between the AMV and Florida summertime rainfall. Finally, using large ensembles from multiple climate models, we show that historical forcing makes models more likely to capture the observed relationship in summer precipitation. Our findings have implications for our understanding of the AMV and for precipitation projections in at-risk South Florida.