Building the Calibration and Validation Roadmap for CRISTAL's Hydro-Cryo Products

In the frame of the ESA CRISTAL IN-PROVA project, NOVELTIS leads an 8-partner consortium establishing the calibration and validation roadmap for CRISTAL’s Level-2 Hydro-Cryo data products, combining direct comparison with reference measurements and cross-validation against other altimetry missions.

The CRISTAL mission, run by ESA within the European Union’s Copernicus programme, represents a major step forward in cryosphere observation. As the first high-resolution, dual-band, interferometric, operational radar altimeter mission, CRISTAL will deliver invaluable data on sea ice, icebergs and land ice, as well as on oceans and inland waters.

CRISTAL IN-PROVA contributes to the mission’s success by establishing a calibration and validation roadmap for CRISTAL’s Level-2 Hydro-Cryo products, covering the cryosphere (sea ice, icebergs and land ice) and inland waters (rivers, lakes). The project combines two complementary approaches: direct comparison with Fiducial Reference Measurements (FRM) – independent, tailored and fully characterised reference data with traceable uncertainty – and cross-validation against other satellite missions such as Copernicus Expansion Missions, including Sentinel-6, CryoSat-2, ICESat-2, SWOT, Sentinel-3 NG Topography, CIMR and ROSE-L.

To strengthen this validation framework, the project includes the development of two dedicated tools: a Validation Performance Simulator, which assesses calibration and validation methods through simulated and co-located datasets aligned with the CRISTAL Mission Requirements Document, and a Match-Up System, which co-locates CRISTAL data with external measurements to enable precise accuracy comparisons.

The project has also grown to include INSIGHT, a platform under development by NOVELTIS. INSIGHT is a European initiative aimed at providing open access to in-situ measurements through a centralized and standardized data hub. The platform’s primary objective is to support calibration and validation (Cal/Val) activities for satellite altimetry, while also serving a broad range of end-users involved in environmental services and studies, as well as hydrological and polar monitoring at both European and international levels.