EOS, a weekly publication of the American Geophysical Union, had a recent article describing how pirate attacks off the Somalia coast have caused the rerouting of ship traffic away from the coast. Many vessels carry surface wind and temperature recording instruments and report these measurements to data collection and analysis stations. There is now a large hole in the wind vector map of the Indian Ocean near Somali which interferes with the mapping of the core region of the Somali Jet. During the Northern Hemisphere summer, this low-level jet originates in a high pressure area east of South Africa, where winds move counter-clockwise toward the east coast of Africa.
High terrain along the African coast prevents the winds from directly crossing the coast. Instead, they are guided parallel to the coast along the Horn of Africa, which projects northeast into the Gulf of Aden. These winds continue on toward India and bring the Indian Summer Monsoon. Wind maps show that some of the Somali jet winds manage to surmount the high terrain of Kenya, Somali, and Ethiopia, and I assume that this has been responsible for orographic rainfall in this region. There is now a catastrophic drought, with refugees massing near the junction of the borders of these three countries.
If solar-heated evaporator rafts might increase the moisture carried by winds over this highland region, it seems that the best location for the rafts is at the northern end of Madagascar. Moisture added at this point might precipitate along the African coast as well as the highlands. The Somali low-level jet might carry some to the Indian coastal mountains where it might contribute to the Indian summer monsoon. In addition to the directional inefficiency, the rafts have a problem with temporal inefficiency because the favorable winds exist for only a few months. During the rest of the year, the rafts deteriorate and require maintenance. If this seems discouraging, remember that Nature is not doing so well these days. We seem to be getting rain in the wrong places, and we have drought in places that humans have settled because the rainfall used to be adequate. So, until somebody comes up with a better idea, I'm going to accept some inefficiency and keep working on the rafts.
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