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Nature.com – May 11, 2007
Lately, it appears that almost every week we get new information regarding the formation of weather on our planet. This article pertains to scientists at Tel Aviv University and Open University in Israel have created a correlation and a theory between thunderstorms in Africa and the birth of hurricanes over the Atlantic Ocean. As you may remember, many people theorize that global warming is the root cause of a major hurricanes like Katrina that struck the Gulf Coast several months ago.
This study goes to the point that we are still learning volumes about our weather. It is not clear that the study is overly conclusive since it appears to only cover 2 years of data and that is probably not enough to create a distinctive trend. Hopefully, these or other scientists will further challenge this hypothesis with a longer term study of this supposed correlation. Also, I hope that our existing climate models will be updated to make this correlation (although most models don’t go to this level of detail).
Africa, climate models, correlation, hurricanes, lightning, ocean, scientists, temperature, weather, wind
What creates an Atlantic hurricane? The most devastating ones are spurred by intense thunderstorms in the Ethiopian highlands, according to new research.
The link between lightning strikes and hurricane formation should give researchers a heads-up about when a nasty hurricane might form, weeks before it could make landfall in the United States, says Colin Price of Tel Aviv University in Israel.
Price and his colleagues at Israel’s Open University studied the 2005 and 2006 hurricane seasons, which were markedly different from each other. In 2005 there were a record 28 named storms, including the catastrophic Hurricane Katrina, while 2006 brought only 10 named storms ó a 64% reduction. Summertime lightning activity in eastern Africa, mainly in the Ethiopian highlands, was also quite different in each of the years, the researchers found, with 23% less activity in 2006 over 2005.
The two phenomena are linked, says Price, an atmospheric scientist who has long studied lightning.
He likens the process to the effect of boulders in a stream: “The boulder produces undulations and turbulence downstream, and the bigger the boulder, the larger the turbulence. Over Africa, thunderstorms act as our boulders.”
This turbulence, in turn, creates low-pressure areas known as African easterly waves (AEW). About half of these systems are known to generate tropical storms as they head westwards over the Atlantic. Various factors, including sea surface temperature, dust and wind shear above the Atlantic, then determine whether those storms strengthen into hurricanes.
Only a fraction of these AEWs go on to make hurricanes or cause damage in the United States. But of the big hurricanes that do form, the vast majority seem to have been born of lightning.