The Southern Oscillation revisited: Sea level pressures, surface temperatures, and precipitation

An update is given of the global correlation and regression patterns of sea level pressure associated with the Southern Oscillation, based upon the re analyses from the National Centers for Environmental Prediction-National Ce nter for Atmospheric Research for 1958-98, a period independent of that of early work. Features over the oceans are better defined than was previously possible and most features prove to be robust, although climate changes su ch as the 1976 climate shift have evidently altered some important relation ships, such as those with Southeast Asia. Associated surface temperature pa tterns are also shown over the same interval and reveal striking symmetry a bout the equator. For El Nino, the patterns emphasize the associated broad warming over the tropical central and eastern Pacific, as well as along the west coast of the Americas extending into high latitudes of the Pacific in both hemispheres, and cooling in the central North and South Pacific. Prec ipitation patterns associated with the Southern Oscillation are given based upon the post-1979 period to include satellite data over the oceans, which emphasizes that the main changes are for a global redistribution of precip itation, so that solely land-based perspectives are biased. While annual me an patterns reveal much of the geographic structure associated with the Sou thern Oscillation, important seasonal variations are present, especially fo r sea level pressure and precipitation.