# Consolidating ICESat-2 Ocean Wave Characteristics with CryoSat-2 during the CRYO2 ICE Campaign
## 6 Conclusions  
Data from CryoSat-2 and ICESat-2 during the CRYO2 ICE campaign have been compared for a full year using three ICESat-2 models: ATL12, the model based on the individual surface waves, and a baseline model using the standard deviations. The CryoSat-2 data have been compared with data from in situ stations to validate the observations, and the comparison with ICESat-2 has been done with this corrected data. A comparison of CryoSat-2 and Sentinel-3A/B and SARAL has also been done; it shows good agreement between the altimeters. The data have been sorted to find coincident orbit segments for CryoSat-2 and ICESat-2 that contain ocean observations from the Pacific or Atlantic oceans, including the Bering Sea. In these regions, we found good agreement between the models, with a correlation for ATL12 from ICESat-2 of 0.97, and the standard deviation model had a similar correlation; however, the histogram model is more scattered, with a correlation of 0.95. The models were compared to CryoSat-2 to analyze differences in their behavior, and while the mean deviation of ATL12 was negatively biased compared to CryoSat-2, it had a small RMSE of 0.29 m, while the more scattered histogram model had an RMSE of 0.42 m. The histogram model based on the measured waves experienced a larger positive deviation (0.18 m) at low SWHs (0-1.5 m) and a larger spread than the other models; however, it did have an RMSE in line with a previous analysis [3]. The number of observations at high SWHs (>8 m) is low, and so the behavior of the models is not well-determined for high SWHs. While ICESat-2 and CryoSat-2 have a smaller correlation, due to the time difference between measurements (2.3 h to 3 h), than comparisons performed for smaller time lags (below one hour), this is in line with the known decrease of the correlation that occurs for longer time lags. Based on the comparison at coincident orbits with CryoSat-2, it can be seen that ICESat-2 is able to provide important additional information about the ocean surface that can be used along with information from conventional altimeters, but it is sensitive to the observation conditions. Conceptualization, B.N., O.B.A., H.R. and M.L.R. ; methodology, B.N. ; software, B.N. ; validation, B.N. ; formal analysis, B.N. ; supervision, O.B.A. and H.R. ; investigation, B.N. ; resources, O.B.A. and H.R. ; data curation, B.N. ; writing--original draft, B.N. ; writing--review and editing, B.N., O.B.A. and H.R. ; visualization, B.N. ; project administration, B.N. and O.B.A. ; funding acquisition, O.B.A. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. * **Data Availability Statement**: CryoSat-2 RADS data are accessible on the DEOS: Rads website: [[http://rads.tudelft.nl/rads/data/authentication.cgi](http://rads.tudelft.nl/rads/data/authentication.cgi)]([http://rads.tudelft.nl/rads/data/authentication.cgi](http://rads.tudelft.nl/rads/data/authentication.cgi)) (accessed on 26 August 2021). Sentinel-3A/B and SARAL RADS data are accessible on the DEOS: Rads website as well (accessed on 10 January 2022). In situ data from the North West Shelf Data Portal are accessible on the website [[http://nwsportal.bsh.de/](http://nwsportal.bsh.de/)]([http://nwsportal.bsh.de/](http://nwsportal.bsh.de/)) (accessed on 10 January 2022). NASA's ICESat-2 data can be downloaded from the NSIDC website. ATL03: [[https://nsidc.org/data/ATL03](https://nsidc.org/data/ATL03)]([https://nsidc.org/data/ATL03](https://nsidc.org/data/ATL03)) (accessed on 26 August 2021). ATL12: [[https://nsidc.org/data/atl12](https://nsidc.org/data/atl12)]([https://nsidc.org/data/atl12](https://nsidc.org/data/atl12)) (accessed on 26 August 2021). We thank the NASA National Snow and Ice Data Center (NSIDC) and the Radar Altimeter Database System (RADS) for distributing the satellite altimetry data, and the North West Shelf Data Portal for the in situ data. We would also like to thank the reviewers for their feedback, which helped improve this paper.