Intensification of Summer Rainfall Variability in the Southeastern United States during Recent Decades

Abstract

The variability of summer precipitation in the southeastern United States is examined in this study using 60-yr (1948-2007) rainfall data. The Southeast summer rainfalls exhibited higher interannual variability with more intense summer droughts and anomalous wetness in the recent 30 years than in the prior 30 years . Such intensification of summer rainfall variability was consistent with a decrease of light (0.1-1 mm day 21 ) and medium (1-10 mm day 21 ) rainfall events during extremely dry summers and an increase of heavy (.10 mm day 21) rainfall events in extremely wet summers. Changes in rainfall variability were also accompanied by a southward shift of the region of maximum zonal wind variability at the jet stream level in the latter period. The covariability between the Southeast summer precipitation and sea surface temperatures (SSTs) is also analyzed using the singular value decomposition (SVD) method. It is shown that the increase of Southeast summer precipitation variability is primarily associated with a higher SST variability across the equatorial Atlantic and also SST warming in the Atlantic.

How do extreme drought and plant community composition affect host plant metabolites and herbivore performance?

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Contribution of the North Atlantic subtropical high to regional climate model (RCM) skill in simulating southeastern United States summer precipitation

“…Experiments utilizing the four dimensional data assimilation technique further suggest that the improved 1996; Manuel 2008;Martinez et al 2009). In recent decades, water supplies in the area have become increasingly stressed due to the population and economic growth (e.g., Manuel 2008;Seager et al 2009;Wang et al 2010). Accurate summer rainfall simulation is thus increasingly important, as it provides a scientific basis for climate prediction and water management for the region.…”

“…For example, summer rainfall is often generated from mesoscale convection cells (e.g., Baigorria et al 2007), landfalling hurricanes (e.g., Hart and Evans 2001;Knight and Davis 2007;Kunkel et al 2010), passages of fronts (e.g., Kunkel et al 2012), and planetary-scale circulation systems (e.g., Henderson and Vega 1996;Li et al 2011Li et al , 2012a. Furthermore, both local and remote climate factors, such as soil moisture and sea surface temperatures (SSTs), can regulate SE US summer precipitation by modulating the abovementioned rainfall generation systems (e.g., Anchukaitis et al 2006;Wu et al 2007;Wang et al 2008Wang et al , 2010Xue et al 2012;Li et al 2012a).…”