Climate Fact: Climate and North Atlantic Hurricanes
The torrential rainfall and storm surges associated with hurricane landfall events can cause what are known as “overwash deposits” that leave definitive marks in the sediment layers that accumulate in coastal areas. Analyses of sediment cores from various locations along the Eastern Seaboard and Puerto Rico show that for the last 1500 years, Atlantic Hurricanes are more frequent when a) the El Niño-Southern Oscillation is in a La Niña phase, which reduces the amount of vertical wind shear over the North Atlantic and b) the North Atlantic is relatively warm, which usually coincides with positive phases of the Atlantic Multidecadal Oscillation. Over the 20th century, ocean temperatures in the North Atlantic main development region warmed during peak hurricane season, with the most pronounced warming occurring over the last four decades.
To view the chart of 20th century North Atlantic main development region peak hurricane season SST’s visit: http://www.earthgauge.net/climate-facts-image-library#6. This image is featured in the “Global Climate Change Impacts in the United States” report recently published by the U.S. Global Change Research Program. The image is in the public domain.
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Sources: Global Climate Change Impacts in the United States, Thomas R. Karl, Jerry M. Melillo, and Thomas C. Peterson, (eds.). Cambridge University Press, 2009 and Mann, ME et al. “Atlantic hurricanes and climate over the past 1,500 years.” Nature 460 (2009): 880-883.