CoAuthors

Alejandro Egido (ESTEC/ESA, Netherlands); Donghui Yi (GST/NOAA, United States); Walter H.F. Smith (NOAA, United States); Laurence Connor (NOAA, United States); Eric Leuliette (NOAA, United States)

Satellite altimetry provides insights about sea-ice, such as the freeboard or sea-ice thickness. Since the start of the first synthetic aperture radar (SAR) altimeter mission CryoSat-2 in 2010 it has been possible to retrieve sea-ice parameters with a significantly higher signal to noise ratio and a better along-track resolution of about 300 meters compared to the low resolution mode (LRM) that provides an along-track resolution of several kilometers. However, retrieving sea-ice parameters from altimetry observations is still a challenging task, due to heterogenous scattering mechanics.

In this study we investigate how lessons learned from ocean observations can help to improve the overall quality of sea-ice parameter retrievals. Mainly we will focus on stack retracking, which in the open ocean allows for the estimation of additional parameters, and the zero skewness (ZSK) transform, which brings stack samples closer to a normal distribution.

Here we will use Sentinel-3A stack data located in the Arctic Ocean – processed using our in-house experimental L1A altimetry data processor – and new numerical stack retracker scheme adapted for sea-ice surfaces. We will study floe, lead, and the mix of floe and lead surfaces. In particular, we will demonstrate how snow-covered sea-ice can be handled in stack retracking and what kind of parameters can be retrieved from these cases.