Tropical instability waves linked to sea surface salinity anomalies

Stretching westward from the South American coast, a tongue of cold water straddles the equator, reaching at times clear across the Pacific Ocean. The behavior of this cold tongue affects the marine ecosystem within its reach and influences the global climate through the El Niño–Southern Oscillation. The Pacific cold tongue is mirrored in the Atlantic, though that version is much weaker and less well defined. In the Pacific, westward propagating waves can periodically radiate outward from the South American coast. Known as tropical instability waves (TIWs), they give the cold tongue's edges a ribbed appearance when observed from space. TIWs are already associated with anomalous sea surface heights and temperatures, surface winds, chlorophyll concentrations, and ocean circulation patterns. Research by Lee et al. provides the first observational evidence of sea surface salinity anomalies associated with TIWs.