CoAuthors

Mònica Roca i Aparici (isardSAT S.L., Spain); Chris Ray (isardSAT S.L., Spain)

Altimetric measurements are key for a variety of areas in geoscience, such as studies on ocean weather, surface wave forecasting, or the assessment of climate change and its impacts. SAR mode altimetric records are used to estimate geophysical parameters over water, such as sea level or wave heights, with high resolution and accuracy required by scientific studies. In addition, strong requirements on the precision are to be met in certain applications. A number of novel theoretical ocean retrackers have been developed to improve the performance of relevant parameters. In this study, an in-house Delay-Doppler (DD) processor for satellite altimetric measurements has been adjusted to include the Amplitude Compensation and Delay Compensation (ACDC) retracking algorithm with the aim to improve the precision of parameter estimates over open ocean. The algorithm exploits intrinsic characteristics of the DD stack deduced from the SAR altimeter analytical model developed in the framework of the SAMOSA project to construct a new ACDC stack. The subsequent multilook operation results in a strong reduction of the speckle noise near the leading edge of the waveform, allowing for an improvement of the precision of the fitted parameters. The performance of the retracking algorithm is assessed by the evaluation of different metrics computed over time series of geophysical parameters retrieved from S3A SAR mode Level-1 products covering an extended spatio-temporal domain.