Declassified high-resolution visible imagery for Arctic sea ice investigations: An overview

Since 2009, subsets of declassified satellite images of Arctic sea ice have been released as literal image derived products (LIDPs) with one-meter resolution for scientific use. The collections include imagery acquired over six fixed locations in the Arctic Basin since 1999. Targeted acquisitions over drifting ice parcels, from 2009 on, provide an added dimension to the LIDP archive. This mode of acquisition is especially useful for capturing time-varying processes during the melt season. In this paper, we describe the characteristics of LIDPs, the extent of the current archive, and highlight their uses for Arctic sea ice science. At this writing, the archive of LIDPs is still quite limited, and thus this paper illustrates the potential utility of the imagery. We provide an overview of the retrieval of five sea ice parameters that would benefit significantly from the surface details afforded by the higher resolution LIDPs. They include: melt pond coverage, open water fraction, ridge height, floe size, and, openings and closings. Two other uses are suggested: measurement of lateral melt and the interpretation of radar backscatter. The intent is to motivate geophysical uses of the LIDP and future acquisitions. Results here suggest that the effective observations of sea ice parameters and especially their changes require more focused sampling strategies to address specific spatial and temporal sampling needs. Presently, acquisitions of this type of imagery at fixed locations and drifting sites are being continued, and LIDPs are added to the archive as they are released.