1. Satellite data:
（1）Envisat：
Basic information: Operated from June 2002 to April 2012, and carried a Ku-band Radar Altimeter-2 (RA-2) radar altimeter.
Related product data: University of Hamburg ( https://earth.esa.int/web/guest/-/ra-2-sensor-data-record-1471 ), where the sea ice freeboard height inversion mainly uses semi-empirical tracking method, and used the hydrostatic balance formula to convert sea ice freeboard to sea ice thickness, and the time range was October 2002 to March 2012.
（2）CS-2:
Related information: carries a Ku-band synthetic aperture interferometric radar altimeter. There are three observation modes: synthetic aperture radar mode (SAR), interferometric synthetic aperture radar mode (SARIn) and low resolution mode (LRM). Among them, the SAR mode is used to observe sea ice; the LRM mode is used for oceanographic mapping; and the SARIn mode is often used to observe coastal zones.
Related product data: There are three types: ESA, AWI and NSIDC. They use different sea ice freeboard height retrieval methods, all of which are on a monthly scale, excluding May-September each year, with a spatial resolution of 25 km.
①ESA: Provide L1b, L2, and L2I three levels of product data. L1b data is composed of echoes of satellite ground track points. For L1b products, the OCOG waveform re-tracking algorithm is used to obtain L2 data. On the basis of L2, L2I adds area surface identification information for calculating sea ice freeboard height (ftp : //sciencepds.cryosat.esa.int ).
② AWI : The time range is from November 2010 to April 2018. ( http://data.meereisportal.de/data/cryosat2/version2.0/ ; Ricker et al., 2014).
③NSIDC:（https://nsidc.org/data/RDEFT4/; Kurtz et al. 2014）
2. Verify data
Airborne Operation IceBridge
Basic information: The airborne OIB observation is to make up for the data gap between the two satellites ICESat-1 and ICESat-2. Since 2009, the laser radar altimeter and other instruments are used in Canada and Greenland during March-May every year. Sea ice observations are made in the thick ice area north of the island.
L4 data includes sea ice thickness, sea ice freeboard height, snow freeboard height (sum of snow depth and sea ice freeboard height), snow depth, etc.
3. Model data:
PIOMAS
Basic information: The model provides monthly averages of sea ice thickness, sea ice concentration, and sea ice velocity for the time range 1979 to 2018. However, PIOMAS is a sea ice-ocean model without atmospheric model components, so it will affect the accuracy of its calculated sea ice parameters.
（http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/data/model_grid）