Extreme weather: A look from the lagoon
Changes in the El Niño/Southern Oscillation and the strength of the West African monsoon have played an important part in controlling the frequency of intense hurricanes in the tropical North Atlantic over the past 5,000 years, a study suggests.
Jeffrey P. Donnelly and Jonathan D. Woodruff constructed a long-term record of intense hurricane activity in the western tropical North Atlantic Ocean. Storms associated with intense hurricanes that strike the island of Vieques in Puerto Rico deposit layers of coarse, sandy material in a lagoon, so the authors used sediment cores from the lagoon to reconstruct the frequency of intense hurricanes in this area over the last 5,000 years.
Their record shows striking similarities to records of El Niño events and rainfall in tropical Africa, suggesting that changes in the El Niño/Southern Oscillation and the strength of the West African monsoon had an important role in controlling the frequency of intense hurricanes in the tropical North Atlantic over this interval.
The lengthy time-interval studied helps to clarify the factors that control hurricane activity, because instrumental records only cover the past few decades. Furthermore, the results suggest that it is important to understand how the El Niño/Southern Oscillation and the West African monsoon will respond to future climate change to accurately predict changes in intense hurricane activity.
CONTACT
Jeffrey P. Donnelly (Woods Hole Oceanographic Institution, MA, USA)
Tel: +1 508 294 2994; E-mail: jdonnelly@whoi.edu