Impact of spatial aliasing on sea-ice thickness measurements

• Published in: Annals of glaciology Vol. 56; no. 69; pp. 353 - 362
• Main Authors: Geiger, Cathleen, Müller, Hans-Reinhard, Samluk, Jesse P., Bernstein, E. Rachel, Richter-Menge, Jacqueline
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 2015
• Subjects: ice physics; ice and climate; sea ice; snow/ice surface processes; volume scaling methods
• ISSN: 0260-3055; 1727-5644
• DOI: 10.3189/2015AoG69A644

We explore spatial aliasing of non-Gaussian distributions of sea-ice thickness. Using a heuristic model and >1000 measurements, we show how different instrument footprint sizes and shapes can cluster thickness distributions into artificial modes, thereby distorting frequency distribution, making it difficult to compare and communicate information across spatial scales. This problem has not been dealt with systematically in sea ice until now, largely because it appears to incur no significant change in integrated thickness which often serves as a volume proxy. Concomitantly, demands are increasing for thickness distribution as a resource for modeling, monitoring and forecasting air–sea fluxes and growing human infrastructure needs in a changing polar environment. New demands include the characterization of uncertainties both regionally and seasonally for spaceborne, airborne, in situ and underwater measurements. To serve these growing needs, we quantify the impact of spatial aliasing by computing resolution error (E r) over a range of horizontal scales (x) from 5 to 500 m. Results are summarized through a power law (E r= bxm ) with distinct exponents (m) from 0.3 to 0.5 using example mathematical functions including Gaussian, inverse linear and running mean filters. Recommendations and visualizations are provided to encourage discussion, new data acquisitions, analysis methods and metadata formats.