Analysis of sea-state bias for the ERS satellites

Abstract

The sea-state bias for altimeter satellites is a combination of the electro-magnetic bias due to the non-Gaussian distribution of reflecting facets (with a bias towards the trough of a wave) and characteristics of the onboard tracker. Although certain characteristics of the sea-state bias are well-known such as a dependence on SWH and wave age all theoretical approaches have proved deficient in correcting for the bias to the extent that it has been necessary to estimate the correction for each satellite altimeter using methods which have included crossover and repeat pass difference analyses. In this study the sea-state bias for the ERS satellites has been determined globally and regionally from crossover residuals as a function of SWH, wind speed and wave age. The impact of the derived parameterisation on the absolute range bias calibrations is assessed.

Keywords:sea-state bias

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry