W. Aldenhoff, C. Heuzé, and L.E.B. Eriksson (2019) Sensitivity of Radar Altimeter Waveform to Changes in Sea Ice Type at Resolution of Synthetic Aperture Radar, Remote Sensing special issue Combining Different Data Sources for Environmental and Operational Satellite Monitoring of Sea Ice Conditions, 11, 2602, doi: 10.3390/rs11222602.
So far, radar altimetry has been mainly used to retrieve basin-wide, monthly sea ice statistics. We argue that it is a wasted potential, and, following the pilot study described in paper , investigate how much SAR backscatter and altimetry could augment each other for sea ice retrieval.
Data: coincidental altimeter tracks from CryoSat2 and backscatter images from Sentinel 1 A/B over the Beaufort Sea, Arctic, in winters 2016, 2017 and 2018.
Method: identify altimeter waveform parameters that best distinguish leads, first year ice (FYI) and multiyear ice (MYI), using the Sentinel 1 backscatter as reference.
Main finding: see Figure 4, reproduced below – each parameter has different strengths and overlaps. Looking at the various years reveal that this finding is robust though. The only problem comes from small scale features, e.g. a MYI floe embedded in FYI
Waveform parameters of different ice types covering all winter seasons 2016-2018 in the Beaufort Sea. (a) Pulse peakiness, (b) scaled mean power, (c) stack standard deviation and (d) mean HV backscatter intensities of altimeter footprint (see paper). Adapted from Aldenhoff et al. (2019), Figure 4.
Conclusion: it works for this purpose, but as we detail in the paper, we have serious doubts regarding our ability to improve freeboard retrievals with this method. To be continued…