RELATION BETWEEN EQUATORIAL OCEANIC ACTIVITIES AND LOD CHANGES

The time series of the length of day (LOD) and the observational Pacif ic sea level during 1962.0 - 1990.0 are used to study the relation bet ween Earth rotation and equatorial oceanic activities. The results sho w that (i) the sea level is apparently rising at an average rate of ab out 1.75 +/- .01 mm/a during the past 30 years; (ii) there are large-s cale eastward and westward water motions in the upper equatorial Pacif ic zone, which, according to the dynamical analysis of the angular mom entum of the large-scale sea water motion in Pacific Ocean related to the Earth rotation axis accounts for about 30% of the change in intera nnual Earth rotation rate; (iii) the interannual changes in Earth rota tion also cause changes in the distribution of the water mass in equat orial Pacific, and affect the formation of ENSO events. Based on these results, we give a new model for the interaction between equatorial o cean and Earth rotation.