Influence of wet tropospheric correction on mesoscale dynamic topography as derived from satellite altimetry

We study the influence of the wet tropospheric correction on mesoscale dynamic topography as derived from satellite altimetry. For this purpose, we use Geosat altimeter data in the northeast Atlantic, and we process separately the tropospheric correction derived from the PERIDOT model following the technique for analysing altimeter height profiles. We show that the humidity spatial scales are larger than those of the dynamic topography. Consequently, the wet tropospheric effect is considerably reduced when orbit error corrections are applied; after long-wavelength filtering, the along-track rms of the correction is 13% of that of the oceanic signal. In addition, contrary to the dynamic topographic signal, the tropospheric signal is temporally decorrelated between two successive adjacent tracks so that the wet tropospheric contribution to the objectively analysed synoptic maps is only 10% of the signal of mesoscale variability.