A monthly Arctic sea ice thickness product from 1995 to 2023 using multiple radar altimetry data

Abstract. Arctic sea ice plays a crucial role in studies of regional and global climate change. Satellite observations have shown that the extent of Arctic sea ice has been declining over the last four decades. However, long-term variations in Arctic sea ice thickness (SIT) have received less attention because SIT cannot be measured directly by satellite-based instruments. Here, we present a monthly Arctic SIT product based on multiple radar altimetry observations from ERS-2, Envisat, and CryoSat-2. To ensure the accuracy of the SIT retrievals, a novel data processing method is proposed, including leads detection, freeboard conversion to thickness, and inter-mission bias correction. Finally, the monthly SIT estimates for the Arctic Ocean from October 1995 to December 2023 are generated. The thickness estimates are posted on a 5 km resolution polar stereographic grid. The variations in Arctic SIT are analyzed in terms of spatial and temporal distributions. Furthermore, the SIT estimates are compared with observations from upward-looking sonars and airborne laser altimetry from Operation IceBridge, as well as seven publicly released Arctic SIT products. The validation results demonstrate that our SIT product has accuracy equivalent to existing products. The accuracy of our products varies from 0.2 m to 0.4 m according to the input satellite altimetry data. The SIT datasets are available on the Zenodo at https://doi.org/10.5281/zenodo.13699698 (Xiao et al., 2024).