Decadal and centennial variability of the southern semiannual oscillation simulated in the GFDL coupled GCM

Abstract

We investigate the behavior of the semiannual oscillation (SAO) in surface pressure and 500 hPa baroclinicity at high southern latitudes in a 1000-year GFDL coupled ocean-atmosphere GCM run. The model represents this feature but is shown to under-estimate its amplitude and percentage of variance explained in the midlatitudes. South of 60°S the simulation of the pressure oscillation, although somewhat too weak, is considerably better. Our analysis reveals significant interannual, decadal and centennial variability in the modeled SAO. While there is only a short historical record of observational data in the middle and high southern latitudes, existing studies suggest that the strength of the ..