Code for Dynamic redistribution enables seasonal reversal of Arctic sea-ice anomalies

Sea-ice motion data were obtained from the NSIDC Quicklook Arctic Weekly EASE-Grid Sea Ice Motion Vectors, Version 1 (NSIDC-0748; doi.org/10.5067/O0XI8PPYEZJ6). ERA5 monthly mean single-level fields are available from the Copernicus Climate Data Store (doi.org/10.24381/cds.f17050d7), and ERA5 monthly mean pressure-level fields are available at doi.org/10.24381/cds.6860a573. The INTAROS-opt ocean-sea-ice reanalysis used for the process-based sea-ice tendency diagnostics was produced using the adjoint-based MITgcm system described by Lyu et al. (2021, 2025).

The model configuration and outputs associated with the Lyu et al. (2025) experiments are publicly available through Zenodo (doi.org/10.5281/zenodo.14584780), with the modified MITgcm code available at doi.org/10.5281/zenodo.14584929. The extended 2007-2025 INTAROS-opt fields used in this study are available at <a href="dx.doi.org/10.12157/IOCAS.20260819.001" target="_blank">dx.doi.org/10.12157/IOCAS.20260819.001</a>.</p><p dir="ltr">Lyu, G., Koehl, A., Serra, N., Stammer, D. & Xie, J. Arctic ocean–sea ice reanalysis for the period 2007–2016 using the adjoint method. <i>Quarterly Journal of the Royal Meteorological Society</i> 147, 1908–1929 (2021).</p><p dir="ltr">Lyu, G. <i>et al.</i> Adjoint-based simultaneous state and parameter estimation in an Arctic Sea Ice-Ocean Model using MITgcm (c63m). <i>Geosci.

Model Dev.</i> 18, 9451–9468 (2025).</p>