Short-Term Climate Variations: Recent Accomplishments and Issues for Future Progress

A short nontechnical review of the El Niño-Southern Oscillation (ENSO) phenomenon and the associated teleconnections to higher latitudes is given. ENSO has been shown to be predictable to some degree for over a year ahead, which therefore provides a basis for skillful prediction of interannual variations in climate. The processes involved are emphasized in order to highlight the areas where future research may most profitably be directed to improve climate forecasts. This progress has been realized through the successful completion of the Tropical Oceans Global Atmosphere (TOGA) Program of the World Climate Research Program (WCRP), which has established and maintained the TOGA Observing System, developed coupled atmosphere-ocean models of the tropical Pacific Ocean, demonstrated the predictive capabilities noted above, and conducted field programs to further the understanding of physical processes. Future research will take place in the context of a developing infrastructure associated with operational climate forecasts. Short-term climate variability involves much more than ENSO, and the challenge is to also capitalize on long timescales associated with anomalies in other parts of the climate system and any additional predictability that goes beyond simple persistence and build this into any prediction scheme. The international framework for helping to facilitate future research is CLIVAR-GOALS, the WCRP program on climate variability and predictability, and the subprogram on the Global Ocean-Atmosphere-Land System. The research challenges are many, but the prospects are excellent for making further advances and the potential is high for socioeconomic benefits for many countries. Turning skillful but uncertain forecasts into useful information and beneficial decisions represents a particular challenge, so that collaboration will be required between the physical scientists and scientists from the applications and social science communities.