Earth’s global temperature has been rising gradually over the last decades, but the warming has not been the same everywhere. Scientists are therefore trying to pin down how the warming has affected regional climates because that is what really matters to people, and to adaptation and mitigation strategies. Their efforts, however, had hit a roadblock because the necessary observations of the winds over the oceans were biased.
Developing a new method to remove the bias, Hiroki Tokinaga and Shang-Ping Xie at the International Pacific Research Center, University of Hawaii at Manoa, found that their corrected observations show the trade winds in the tropical Atlantic have weakened and the pattern of ocean surface temperature has changed. As a result, the equatorial Amazon and the Guinea Coast are seeing more rainfall and the Sahel less. The findings are published online in the February 6, 2011, issue of Nature Geoscience.