Contrasting observed and CMIP3 simulated sea surface salinity in the tropical Pacific

This presentation aims at: a) documenting the main modes of the tropical Pacific Sea Surface Salinity (SSS) variability during the 1950-2008 period based on an unprecedented collection of in situ observations, and b) assessing how these modes are simulated in 23 coupled models of the WCRP CMIP3. The emphasis is on seasonal and ENSO (El Nino Southern Oscillation) time scale variations as well as long-term (50 year) trends. It will be shown that most CMIP3 coupled models poorly reproduce the dominant time-varying SSS modes. The reasons for this poor representation of SSS, and the implications for model projections of future climatic conditions, will be discussed.