Interdecadal variations in global climate and earth rotation rate

摘要

A science plan for future 1.5 a, "A Study of Climate Variability and Predictability" (CLI-VAR), was published by WMO in 1996. As the plan treated interdecadal climatic variability as a sub-plan, it showed that this problem is very important, By the implementation of "Tropical Ocean and Global Atmosphere" (TOGA) 10-a plan during 1985--1994, the interdecadal variability that occurred in ENSO (El Nino/Southern Oscillation) ocean-atmosphere interaction has been found. This variability made the traditional ENSO prediction pattern useless in the 1980s, and the forecasting of coupled model and observation of sea surface temperature (SST) anomaly were discrepant from 1992 to 1995. In the late 1970s, the tropical Pacific experienced an abrupt interdecadal warming and changes of atmospheric circulation. This phenomenon was referred to as interdecadal variation. The characteristic of the onset of El Nino events (1982, 1986 and 1991) has experienced notable change since the late 1970s in combination with the composition analysis of El Nino events during 1950--1976. Another characteristic that the frequency of interannual warming has been increased since the 1990s was also noted. The global climatic changes are intimately linked to the equatorial SST anomaly so that the equatorial SST anomaly has become an important index for forecasting global climatic changes. However, the interannual SST anomalies are affected by the interdecadal change of the background state, so the mechanism and prediction of interdecadal climatic anomalies have become a typical topic.