Seasonal sea level change from TOPEX/Poseidon observation and thermal contribution

Seasonal steric sea-level change due to temperature variation in the mixing layer is assessed using space-measured sea-surface temperature data and hi storical in situ temperature measurements. The results are compared with TO PEX/Poseidon satellite: altimeter measurement at different large spatial sc ales. It is indicated that thermal effect accounts for much of the observed seasonal variability, especially when averaging over zonal regions. Some r egional seasonal patterns of sea-level anomalies in the tropical oceans are well represented by the thermal model prediction. Systematic differences a re shown between TOPEX/Poseidon observation and thermal contribution at a 1 -2 cm level. The potential causes for these differences are discussed, incl uding water mass exchanges among the atmosphere, land, and oceans, and erro r sources in the steric result and geophysical corrections applied in TOPEX /Poseidon data.