Abstract's details

Propagating uncertainties and error correlation structures through retracking and sea state bias correction

Sajedeh Behnia (National Physical Laboratory, United Kingdom)


Jonathan Mittaz (Reading University, United Kingdom); Hannah Cheales (NPL, United Kingdom); Emma Woolliams (NPL, United Kingdom)

Event: 2022 Ocean Surface Topography Science Team Meeting

Session: Quantifying Errors and Uncertainties in Altimetry data

Presentation type: Type Poster

Contribution: PDF file


What is the uncertainty budget in deriving Global Mean Sea Level (GMSL) from satellite altimetry? This is one of the questions to be addressed within the framework of the ESA-funded project Assessment Sea Level rise Stability Uncertainty, ASeLSU. ASeLSU is approaching this question in a metrological manner which entails a full breakdown of all sources of uncertainties arising from the altimeter and assessment of error correlation structures to quantify the uncertainty budget.

From acquiring the radar backscatter to forming a waveform and estimating the GMSL, many processing steps are involved, which makes the uncertainty analysis intricate. This is especially true considering that components such as the altimetric range and sea state bias correction are not derived independently. Four primary parameters – epoch, sigma-0, significant wave-height, and mis-pointing angle – are derived from the most common retracking used MLE4 (Amarouche et al., 2004). Two of these parameters, sigma-0 and significant wave-height, are used to estimate the wind speed, which in turn is used with significant wave-height (again) to determine the sea state bias correction.

In this study, we performed simulations using simplified retracker algorithms to understand the extent of possible error correlations between the different quantities derived from retracking, and to propagate those through to sea state bias and the ionosphere correction.

Amarouche et al., 2004: https://doi.org/10.1080/01490410490465210


Poster show times:

Room Start Date End Date
Mezzanine Tue, Nov 01 2022,17:15 Tue, Nov 01 2022,18:15
Mezzanine Thu, Nov 03 2022,14:00 Thu, Nov 03 2022,15:45
Sajedeh Behnia
National Physical Laboratory
United Kingdom