Researchers discover natural 150-day period in north-south oscillation of Southern Hemisphere’s westerlies.
Climate scientists at Rice University have discovered an “internally generated periodicity” — a natural cycle that repeats every 150 days — in the north-south oscillation of atmospheric pressure patterns that drive the movement of the Southern Hemisphere’s prevailing westerly winds and the Antarctic jet stream.
“This is something that arises from the internal dynamics of the atmosphere,” said Pedram Hassanzadeh, co-author of a study about the discovery in the open-access journal AGU Advances. “We were playing with some new equations that we had derived for the atmosphere’s turbulent circulation, and we found they predicted the possibility of natural periodicity in the Southern Annular Mode (SAM). We were skeptical, but we went to the observational data and we actually found it.”
Co-author Sandro Lubis said, “It was really a surprise, because it goes against the conventional wisdom that the atmosphere is all chaos and disorganization.”
Read more at Rice University
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