Perhaps you could be more specific with your citation. Nothing jumped out at me. Is this what you're referring to? https://nsidc.org/data/seaice_index/images/

Perhaps you could be more specific with your citation. Nothing jumped out at me. Is this what you're referring to? https://nsidc.org/data/seaice_index/images/s_plot_hires.png https://nsidc.org/data/seaice_index/images/s_plot_hires.png