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No. 87: May-Jun 1993

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Amazons In The Sky

No, we are not talking about the jet streams. Rather, we refer to the curious "filamentary structures" seen on water-vapor maps of the troposphere. (The troposphere is roughly the lower 10-20 kilometers of the atmosphere.) These filaments are many times longer than they are wide, and deserve to be called "rivers." These aerial streams of water vapor develop in regular patterns and persist as they are translated through the troposphere. It is the huge quantity of water vapor carried by these aerial rivers that make them worthy of note here. Especially remarkable is the river that frequently flows south from Brazil to east of the Andes and thence southeast into the Atlantic.

"A typical flow in this South American tropospheric river is very close to that in the Amazon (about 165 x 106 kg sec-1). There are typically five rivers leading into the middle latitudes of the Southern Hemisphere and four or five leading into the Northern Hemisphere. The rivers persist for 10 days or more while being translated generally eastwards at speeds of 6 m sec-1 ."

(Newell, Reginald E., et al; "Tropospheric Rivers?-A Pilot Study," Geo physical Research Letters, 19:2401, 1992.)

From Science Frontiers #87, MAY-JUN 1993. 1993-2000 William R. Corliss