Monthly Harmonized Sentinel-1 and Sentinel-2 dataset over Axel Heiberg Island

The monthly harmonized Sentinel-1 and Sentinel-2 dataset contains monthly, multi-temporal Sentinel-1 and Sentinel-2 mosaics of the ice fields on Axel Heiberg Island in the Canadian Arctic for the years 2017–2023 as GeoTiff files. As part of the Copernicus program, the European Space Agency (ESA) and the European Commission make data from the Sentinel missions available as open data. For the polar regions, monthly Sentinel-1 Level 3 mosaics with dual-polarized images in HH and HV polarization are available. These have a spatial sampling of 40 meters. In addition, ESA offers quarterly multispectral Sentinel-2 Level 2A mosaics with spectral bands B02 (Blue), B03 (Green), B04 (Red), and B08 (Near Infrared, NIR) at a spacing of 10 meters. The Sentinel-2 data were resampled onto the 40 meter grid, subsequently, both the Sentinel-1 and Sentinel-2 data were cropped to the extent of the ice fields. The coordinate reference system for the images is WGS84 / UTM Zone 32N. The quarterly Sentinel-2 mosaics were each assigned a timestamp corresponding to the middle of the respective quarter—thus, images from the first quarter are timestamped February, and so on. To fill in the remaining months with data, a novel gap-filling algorithm (HELIX) was applied, for more detailed information on the methodology see the related work section. The final dataset contains one harmonized gap-filled image per month. Each image contains 6 bands (see table below): Band 1 contains the Sentinel-2 imagery from B02 (Blue), Band 2 contains the imagery from B03 (Green), Band 3 contains the imagery from B04 (Red), and Band 4 contains the imagery from B08 (Near-Infrared). Band 5 and Band 6 contain the Kennaugh elements K0 and K1, respectively, which were calculated from the HH and HV polarizations of Sentinel-1. For more information on the calculation formulas see the related work section.