Impact of spatial aliasing on sea-ice thickness measurements
Date
2015-10-01
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International Glaciological Society
Abstract
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 (Er) over a range of horizontal scales (x) from 5 to 500 m. Results are
summarized through a power law (Er = 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.
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Citation
Geiger, C. A., et al. "Impact of spatial aliasing on sea-ice thickness measurements." Annals of Glaciology 56.69 (2015): 353.