Abstract:
A study of the seasonal effects of interannual and interdecadal climactic influences on southeast U.S. precipitation is presented. Precipitation data was gathered from 183 precipitation gauges provided by The National Oceanic and Atmospheric Administration’s (NOAA) National Center for Environmental Information (NCEI). The phases (warm/positive or cold/negative) of oceanic-atmospheric influences of the Pacific Ocean [El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO)] and the Atlantic Ocean [Atlantic Multidecadal Oscillation (AMO)] were identified for the preceding year (1969-2013) to the precipitation data (1970-2014). Three statistical significance tests (1) two-sample t-test (90% significance), (2) rank-sum (90% significance) and (3) effect-size (threshold of 0.8 to -0.8) were used to evaluate precipitation response to the positive/negative phases of the oceanic-atmospheric influences of the Pacific and Atlantic Oceans. The warm phases of ENSO and PDO were associated with increased annual precipitation in the southeastern region of the United States, while the cold phase of the AMO was associated with increased annual precipitation. While providing affirmation of these associations, this study considers the variation in seasonal precipitation of the southeastern U.S. The results indicate strong winter [January-March (JFM)] signals by all three oceanic-atmospheric influences and a strong summer [July-September (JAS)] signal by the PDO.
