The paper explored the question of whether a steady increase in ocean observations can be discerned in improvements in skill of predicting sea surface temperature (SST) variability associated with El Niño – Southern Oscillation (ENSO). To answer this question, authors analyzed time evolution of skill of sea surface temperatures in the equatorial tropical Pacific since 1982 based on a seasonal prediction system.
The authors found that for forecasts up to six month lead time, a clear fingerprint of increases in sub-surface ocean observations is not readily apparent in the time evolution of prediction skill, which is dominated much more by the signal-to-noise consideration of SSTs to be predicted. Finding no clear relationship between an increase in ocean observations and prediction skill of SSTs, various possibilities are discussed.
This discussion aims to help motivate further exploration on the question of the tropical Pacific Observing System, its influence on the skill of ENSO prediction, and capabilities of current generation of coupled models and ocean data assimilation systems to take advantage of ocean observations.