Abstract's details
Sea State Climate Change Initiative: first steps of the Algorithm Development Team
CoAuthors
Event: 2018 Ocean Surface Topography Science Team Meeting
Session: Instrument Processing: Measurement and Retracking
Presentation type: Type Poster
Contribution: PDF file
Abstract:
From the Satellite Altimetry perspective, the European Space Agency’s Sea State Climate Change Initiative (SS_cci), starting in June 2018, means above all the possibility to perform a vast study focused on the estimation, production and exploitation of a consistent Significant Wave Height and Wind Speed dataset.
The workplan of the algorithm development (AD) team for satellite altimetry in this framework and the implications within the OSTST communities will be presented in this abstract. Firstly, the AD SS_cci team is responsible for the development of new estimation techniques that are able to improve the signal-to-noise ratio of these two parameters. Secondly, it has to guarantee that the strategy of choice is able to deliver estimations that are consistent during the 25 years of altimetry data in terms of biases and, as much as possible, in terms of performances. If on one side this means that the application of the same algorithm to all the missions could be an advantage, on the other side we shall not ignore the wider possibilities and better performances that the Delay-Doppler processing in Cryosat-2 and the Sentinels provide. The team will start the work with several efforts in parallel: the ideas for a subwaveform retracker focused on the wave estimations will be presented, as well as the current status of the Adaptive Numerical Retracker for sea state and advanced techniques to exploit the stack information of SAR altimetry.
The other main duty that the team will perform is the planning of a round-robin open to all external participants, in which the criteria for the evaluation of the algorithms and the final selection shall be established. Aside from typical criteria (bias with buoys, average of the estimation), other priorities in the evaluation of the performances, aimed at maximising the scientific exploitation of the future dataset will be discussed: for example, the accuracy for retrieving large wave heights and the performances in coastal zone. This work, to be performed in collaboration with the other teams of the project, will be beneficial for the whole OSTST community, given the need of drafting a revision of the methodology to compare data coming from different retrackers and missions, which was highlighted in the Splinters of the last years.
Finally, post-processing will also play an important role in the definition of the SS_cci dataset. A new methodological approach will be investigated, based on the use of Empirical Mode Decomposition, an adaptative method which has proved to efficiently remove the noise and to give better results in significant wave height and sea surface height analysis than commonly used smoothing filters.
The workplan of the algorithm development (AD) team for satellite altimetry in this framework and the implications within the OSTST communities will be presented in this abstract. Firstly, the AD SS_cci team is responsible for the development of new estimation techniques that are able to improve the signal-to-noise ratio of these two parameters. Secondly, it has to guarantee that the strategy of choice is able to deliver estimations that are consistent during the 25 years of altimetry data in terms of biases and, as much as possible, in terms of performances. If on one side this means that the application of the same algorithm to all the missions could be an advantage, on the other side we shall not ignore the wider possibilities and better performances that the Delay-Doppler processing in Cryosat-2 and the Sentinels provide. The team will start the work with several efforts in parallel: the ideas for a subwaveform retracker focused on the wave estimations will be presented, as well as the current status of the Adaptive Numerical Retracker for sea state and advanced techniques to exploit the stack information of SAR altimetry.
The other main duty that the team will perform is the planning of a round-robin open to all external participants, in which the criteria for the evaluation of the algorithms and the final selection shall be established. Aside from typical criteria (bias with buoys, average of the estimation), other priorities in the evaluation of the performances, aimed at maximising the scientific exploitation of the future dataset will be discussed: for example, the accuracy for retrieving large wave heights and the performances in coastal zone. This work, to be performed in collaboration with the other teams of the project, will be beneficial for the whole OSTST community, given the need of drafting a revision of the methodology to compare data coming from different retrackers and missions, which was highlighted in the Splinters of the last years.
Finally, post-processing will also play an important role in the definition of the SS_cci dataset. A new methodological approach will be investigated, based on the use of Empirical Mode Decomposition, an adaptative method which has proved to efficiently remove the noise and to give better results in significant wave height and sea surface height analysis than commonly used smoothing filters.