Israeli research on the climate was ranked 25th out of the top 100 studies in the world for 2007.

The study, in which researchers from Tel Aviv University and the Open University participated, discovered a possible connection between lightning in East Africa and hurricanes in the Atlantic Ocean

Global forecasting services are looking for early indicators for an early interpretation of the nature of the hurricane season. Research by Prof. Colin Price (Talo University), Dr. Yoav Yair (Open University) and Dr. Mustafa Asfor (Open University) shows a possible connection between lightning activity in East Africa and the number and intensity of storms in the Atlantic Ocean, and offers a new parameter for early warning of the chances of their formation. The study was published in the important newspaper Geophysical Research Letters and was ranked by the monthly Discovery in the 25th place out of the hundred most important studies in 2007.

The researchers examined the number of lightning strikes in a defined area in East Africa (the Ethiopian plateau), between latitudes 10 and 20 North and 30 to 40 East. The data was obtained based on electromagnetic signals spreading from telegrams in the very-low-frequency (VLF) field collected through a worldwide network of receiving stations, one of whose antennas is located on the Tel Aviv University campus. The lightning activity in Africa was compared to the wind data on meteorological maps in an area from the coasts of Senegal and Mauritania in West Africa to 40 west latitude, which is the area where the storms hit. The main finding shows that before the formation of 90% of the tropical storms and hurricanes in the Atlantic Ocean, the number of lightning in East Africa was higher than average. In addition, the year 2006 was characterized by 36% lower lightning activity compared to 2005, when the number of hurricanes broke records. The researchers found that the intensification of lightning is a week ahead of the formation of storms on the west coast of Africa. Since the lightning data can be tracked in real time, this period of time may allow early warning and preparation.

The physical explanation for this lies in the existence of atmospheric waves moving from east to west over the African continent during the summer season. Every year about 60 such waves are formed and within them storm systems are formed that bring down rains and are also characterized by large amounts of lightning. When the intensity of the lightning storms is intense and their electrical activity is high, the clouds constitute a kind of obstacle to the regular flow of the winds and cause the formation of eddies, similar to large stones found in a stream of water. Downstream, after the obstacle, there is a greater chance of increasing instability and the formation of atmospheric disturbances, which in most cases do grow later and become barometric depressions and large-scale tropical storms. These storms pass over the coast of West Africa, move over the warm waters of the Atlantic Ocean and may strengthen to hurricanes.

The research was supported by the research fund of the Open University.

East African lightning as a precursor of Atlantic hurricane activity

Colin Price, Yoav Yair, and Mustafa Asfur, GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L09805, doi:10.1029/2006GL028884, 2007

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