A global sea level variability study from almost a decade of altimetry

Altimeter data of the GEOSAT, ERS-1 and TOPEX/POSEIDON (T/P) missions have been used to study large-scale seasonal and long-periodic changes in the sea level. The radial orbit error is reduced by crossover minimization. The authors computed large-scale global dynamic topographies with a time resolution of 7 days and a space resolution of about 5°. EOF and DFT analyses show a dominant annual cycle for most regions. Time-longitude sections reveal ENSO warm and cold events accompanied by Kelvin and Rossby waves. A secular change of 4.9 mm/yr is evident both from the ERS-1 and T/P data