Wednesday, 14 January 2009
Trends in the variability of daily high temperatures in the Southeast
Hall 5 (Phoenix Convention Center)
Attempts to discern climate change in the southeastern U.S. have not always shown a clear unambiguous signal of temperature change. Potential interactions between globally increasing carbon dioxide and the effects of expanding urban heat islands on temperatures across the southeastern United States have be challenging to observe and interpret. Changes in the variability of temperature is acknowledged as an important climatic parameter. Many studies have examined decadal, annual, or monthly temperature variability. Fewer studies have explored the variability of daily high temperatures. The variability of daily high temperatures is used here because of its importance in applied climatology where large changes in the daily temperature maximum can approach or exceed thresholds that dramatically impact temperature sensitive operations. Human activities affected by daily high temperatures range from agriculture, construction and electricity generation to health and transportation. In this study the number and magnitude of changes in the daily maximum temperature from one day to the next are utilized as metrics for temperature variability. Four southeastern cities were selected for this study: Atlanta, Birmingham, Charlotte, and Nashville. Descriptive statistics, running averages, and time series trends of these day to day change events are identified as elements of climate change during the past sixty years. These data suggest that daily temperature variability is decreasing at these four southeastern sites. The reasons for this observed decrease in variability are unknown, but possible explanations would include, but are not limited to, urban heat island/airport effects and a reduction in the frequency or intensity of frontally induced changes in the daily temperature maxima.
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