Daily sea ice age data for the entire Northern Hemisphere

Daily sea ice age data for the entire Northern Hemisphere The data were derived from the backward tracking of sea ice, calculated using sea ice velocity (https://doi.org/10.5281/zenodo.17694536) and sea ice concentration from satellite microwave radiometer observations (AMSR-E / AMSR2). See Kimura and Hasumi (submitted: https://egusphere.copernicus.org/preprints/2025/egusphere-2025-3286/) for details of the calculation method. File naming: Before extraction: siaYYYY.zip where YYYY indicates the year. After extraction: siaYYMMDDnh.txt where YY indicates the year, MM the month, and DD the day. Format: Plain text file Each line contains: latitude (N), longitude (E), mean sea ice age (days), oldest sea ice age (days) The number of lines varies seasonally (more in winter, fewer in summer). Data points are located on a 10-km regular grid in polar stereographic coordinates. Coverage: 2007/01/01-2011/09/27 2016/07/16-2022/12/31 (4091 days)