Rare Formation
Typically, tropical cyclones do not form in the South Atlantic Ocean, due to strong upper level shear, cool water temperatures, and the lack of a convergence zone of convection. Occasionally though, as seen in 1991 and early 2004, conditions can become slightly more favorable. For Catarina, it was a combination of climatic and atmospheric anomalies. Water temperatures on Catarina's path ranged from 24 to 25 °C, slightly less than the 26.5 °C temperature of a normal tropical cyclone, but sufficient for a storm of baroclinic origin.
Up to that point, no tropical cyclone had been observed to reach hurricane strength in the South Atlantic Ocean via satellite imagery, which dates back to the mid-1970s. While Catarina formed in an unusual area, its relation to global warming or any other type of global climatic change is still up for debate. The Brazilian Society of Meteorology attributed it to "climatic changes and atmospheric anomalies," while other researchers have indicated that it could be the result of the Southern Annular Mode or other seasonal variations in weather within the Southern Hemisphere, again linked to global changes in climate. However, more research in the area is still needed to make a conclusion.
Read more about this topic: Cyclone Catarina
Famous quotes containing the words rare and/or formation:
“As soon as I suspect a fine effect is being achieved by accident I lose interest. I am not interested ... in unskilled labor.... The scientific actor is an even worker. Any one may achieve on some rare occasion an outburst of genuine feeling, a gesture of imperishable beauty, a ringing accent of truth; but your scientific actor knows how he did it. He can repeat it again and again and again. He can be depended on.”
—Minnie Maddern Fiske (1865–1932)
“The moral virtues, then, are produced in us neither by nature nor against nature. Nature, indeed, prepares in us the ground for their reception, but their complete formation is the product of habit.”
—Aristotle (384–322 B.C.)