Tropical instability waves

A plot of Pacific sea surface temperatures on June 26, 2010. Tropical instability waves are visible as north–south deflections of the tongue of cold water that extends along the equator. These waves propagate westward with a period of about 30 days.

Tropical instability waves, often abbreviated TIW, are a phenomenon in which the interface between areas of warm and cold sea surface temperatures near the equator form a regular pattern of westward-propagating waves. These waves are often present in the Atlantic Ocean, extending westward from the African coast, but are more easily recognizable in the Pacific, extending westward from South America. They have an average period of about 30 days and wavelength of about 1100 kilometers, and are largest in amplitude between June and November. They are also largest during La Niña conditions, and may disappear when strong El Niño conditions are present.[1]

Tropical instability waves are not related to tropical waves, which are atmospheric disturbances that propagate westward along the Intertropical Convergence Zone, sometimes giving rise to tropical storms.

  1. ^ Cite error: The named reference Willett was invoked but never defined (see the help page).