South Carolina's Climate Report Card: The Influence of the El Niño Southern Oscillation Cold Warm Event Cycles on South Carolina's Seasonal Precipitation

Abstract

This study was driven by the need to better understand variations in South Carolina’s seasonal precipitation. Numerous weather-sensitive sectors such as agriculture and water resource management are impacted by the seasonal variability and distribution of precipitation. Studies have shown that El Niño-Southern Oscillation (ENSO) has varying effects on seasonal temperature and precipitation across the United States. The purpose of this study was to determine the relative influence of ENSO cold and warm event cycles on interannual variations of South Carolina’s seasonal precipitation (1950- 2015). The relationship between seasonal precipitation departures from normal and the average Multivariate ENSO Index was analyzed. Seasonal precipitation totals for each of South Carolina’s seven climate divisions and for three key city locations (Greenville-Spartanburg Airport, Columbia Airport, and Charleston Downtown) were examined. Results from the study indicate that the magnitude, seasonal variation, and consistency of the precipitation response to ENSO vary spatially and from episode to episode. Winter precipitation tends to be enhanced during the warm phase (El Niño) and reduced during the cold phase (La Niña). There is a less consistent signal during fall and no evident connection between ENSO and spring and summer precipitation.