Monitoring Global Mean Sea Level Variation with TOPEX/Poseidon Altimetry

Variation of the global mean sea level was extracted with TOPEX/Poseidon altimeter data from January 1993 to May 1999. It is shown that both the improper weighting and error in mean sea level model induce errors in the annual variation of global mean sea level. The error of current ocean tide model affected global mean sea level in the periods of about 60 and 90 days. The significant difference was found between the global mean sea level from TOPEX altimeter and that from Poseidon altimeter, suggesting that TOPEX/Poseidon altimeters need further calibration. The rate of change of global mean sea level derived from TOPEX altimeter and Poseidon altimeter during this period is 2.0mm/yr and -0.5 mm/yr respectively. The correlation between global mean sea level variation and Southern Oscillation Index (SOI) shows that the ENSO event is an possible explaination for the intra-annual variation in global mean sea level.