ENVISAT RA-2 SATELLITE ALTIMETRY IN COASTAL AND INLAND WATERS: A COMPARISON OF RETRACKERS

Radar altimeters made measurements of surface water levels possible from space. The technique was originally designed for use in the open ocean, but now, with more interest in the coastal zone, many in the satellite altimetry community are working on the development of retracking algorithms and improved atmospheric corrections. It is important to recognize that the previous technical challenges are common to satellite altimetry over any water body, but the issues are especially challenging in coastal and inland waters due to their specific morphological and dynamic characteristics. The Envisat RA-2 mission provides a 35- day revisit time, with a maximum of 300 m resolution along track. It has collected altimeter data over the whole globe since 2002. Within the COASTALT project, this historic archive of observations is accessible, with the addition of retrackers optimized for non-open ocean targets. This poster reports the results of analysis of standard and retracked data over an initial selection of water surface targets (coastal zone, estuary and lake), presents examples of time series derived from these data and discusses agreements/disagreements.