Multi-decadal view of temperature extremes across the southeastern United States

For the agricultural community and energy suppliers, insight into the spatial trends and the temporal shifts of distributions of temperature extremes may support decision making on seasonal to annual scales. Temperature extremes are key fingerprints in the identification of climate change. Meehl et al. (2009) compared the counts of record high maximum temperatures to the counts of record low minimum temperatures in the United States. They concluded that the number of record highs exceeded the number of record lows. Their study used a short period of record (1950-2006) for the entire continental United States. Our study focuses on the southeastern United States for a longer period of record (1892-2009). Temperature extremes are assessed through statistical methods that quantify the frequencies of occurrence across Alabama, Florida, Georgia, and the Carolinas. Data are from 113 National Weather Service's (NWS) Cooperative Observing Network (COOP) stations for the period of record; each station dates back to at least 1930. The extremes of the temperature distributions are studied using an eighty-year period (1930-2009) to calculate the 1st and 99th percentiles. The analysis of annual occurrences in daily temperature extremes reveals oscillating, multi-decadal patterns. Future examination of these data may identify predictable patterns of seasonal and spatial variations for temperature extremes within the southeast.