Reconciling Arctic sea ice roughness across four observing platforms: a resolution transfer function and the stability of spectral shape over six decades
Year: 2026
Type: preprint
Abstract: . Sea ice roughness is measured by platforms whose spatial resolutions differ by two orders of magnitude, and the resulting estimates disagree by a factor of four, which has prevented the assembly of a consistent long-term record. Here we analyse ice topography from four platforms within a single broken power law spectral framework: submarine upward-looking sonar (5470 profiles, 43 cruises, 1960–2005), MOSAiC airborne laser scanning (55256 transects), under-ice remotely operated vehicle (ROV) multibeam (52264 transects from 36 dives), and ICESat-2 altimetry (25740 segments). The fourfold spread in the slope-to-amplitude ratio z2/z1 collapses onto a single resolution degradation curve, z2/z1 = 0.218 Δx-0.46 (R2 = 0.92), whose exponent follows analytically from the observed spectral shape rather than being fitted freely; the curve provides a transfer function for inter-calibrating roughness estimates between platforms with effective footprints of 0.5–20 m. The resolution-independent spectral parameters (β1 ≈ -0.5, β2 ≈ -2.2, λbreak ≈ 99 m) are consistent across all four platforms and both ice surfaces, and show no significant trend over the 45-year submarine record despite a halving of mean ice thickness, although that record can only exclude changes larger than about 160 % of the median exponent at 80 % power. Eighty-five paired surface–bottom observations spanning a full MOSAiC year show that the isostatic approximation holds at the derivative level (z2/z1 surface-to-bottom ratio 0.99 ± 0.14, against 0.28 for the amplitude z1), so under-ice morphology can be inferred from satellite surface measurements. That fidelity is seasonal: the ratio is 0.94 ± 0.07 from October to May but reverses to 1.14 ± 0.10 from June to September, when surface melt and basal melt together leave the surface sharper than the underside. Roughness amplitude and spectral shape therefore respond to forcing on different terms: z1 varies sevenfold over the seasonal cycle and has declined with the ice cover, while the shape parameters remain stable to within the tested bounds.
Language: English
Subfield: Atmospheric Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7225321030