Arctic sea surface height maps from multi-altimeter combination

Abstract. We present a new Arctic sea level anomaly dataset, based on the combination of three altimeter missions using an optimal interpolation scheme. Measurements from SARAL/AltiKa, CryoSat-2 and Sentinel-3A are blended together providing an unprecedented resolution for this type of products. The final gridded fields cover all latitudes north of 50° N, on a 25 km EASE2 grid, with one grid every three days over three years from July 2016 to April 2019. We use the Adaptive retracker to process both open ocean and lead echoes on SARAL/AltiKa thus removing the need to estimate a bias between open ocean an ice covered areas. SARAL/AltiKa also provides the baseline for the cross-calibation of CryoSat-2 and Sentinel-3A data. When compared to independent data, the combined product exhibits a much better performance than previously available datasets based on the analysis of a single mission.