15 years of improvements in ocean altimetry performance: a review
8-10 Rue Hermès,
From the ERS-1 and TOPEX/Poseidon launches in the early ninetee’s, Oceanography was radically changed thanks to global and precise observations from satellite altimetry. Since then, a tremendous number of improvements in a wide variety of domains have been brought by extensive studies in different teams all over the world. All these efforts allowed the current situation of high precision multi-mission altimetry. In the same time, studies, applications such as operational oceanography and new fields of investigation have developed and put new requirements on altimetry missions in terms of data availability, accuracy and stability.
A review of the main improvements in altimetry is given, with quantification in terms of performances and identification of the major impacts on applications.
Indeed, great breakthroughs have been achieved in several domains, such as instrument processing, precise orbit determination, geophysical algorithms and corrections, data availability and coverage, but also calibration, cross-calibration and merging techniques. Thus it is important to estimate to what extent each subject contributed (and still contributes) to the overall performance and error budget. Moreover, it is interesting to identify, depending on the nature of each improvement, which cause motivated the change and by which means it was achieved. The impact on the end user applications is of course essential, since it drives the loop between improvements in altimetry, development of new applications and new requirements for altimeter systems.
Finally conclusions are also inferred from this 15 year experience about the efficiency of including validation and performance assessment at each step, and about the great collaborative work that has been set up between operation engineers, project managers, specialists in each domain, scientists and users, each doing his utmost for the same goal in an integrated concept.