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Laboratory for Satellite Altimetry / Sea Ice and Polar Dynamics Science Team

Sea Ice Pressure-Ridge Sail-Height

Figure 1. Pressure Ridge Sail Height geometry
HS = L × tan α

Figure 1. Depiction of geometry used for Sail Height (HS) derivation.

Pressure-ridge sail-height, HS, is defined as the height of the ridge sail above the sea ice surface. HS is derived from high-resolution Digital Mapping System (DMS) imagery acquired in the late winter months of March, April, and May during NASA's annual Operation IceBridge (OIB) airborne campaigns in the Arctic.

The HS algorithm is described in Duncan et al. (2018) and exploits the DMS imagery to identify and measure the length, L, of shadows cast by pressure ridge sails in the sea ice cover. HS is derived by combining L with knowledge of the solar elevation angle, α (Figure 1).

Figure 2. Map of Pressure Ridge Sail Heights

Figure 2. Mean HS between March and May, 2010–2018, for 25 km along-track segments per flightline.

Data Product and Data Access

The NOAA / NESDIS / STAR / Laboratory for Satellite Altimetry (LSA) Polar Ocean Data System (PODS) Arctic Sea Ice Sail-Height is derived from high-resolution DMS imagery of sea ice pressure ridges acquired during annual, low-elevation NASA OIB airborne surveys over Arctic sea ice. DMS imagery were acquired between March and May, 2010-2018 (Figure 2). Statistics describing pressure ridge sails are extracted per image. Arithmetic averages are computed for 25 km along-track segments for each aircraft flight line, in the absence of clouds, polar darkness and sea ice leads.

Acknowledgment: Users are free to use the information hosted on this site in their research, provided credit is given to the NOAA / NESDIS Center for Satellite Applications and Research (STAR) Laboratory for Satellite Altimetry (LSA). Users are also asked to cite the following publication whenever these data are used: Duncan, K., Farrell, S., Connor, L., Richter-Menge, J., Hutchings, J., and Dominguez, R. (2018). High-resolution airborne observations of sea-ice pressure ridge sail height. Annals of Glaciology, 59(76), 137-147. DOI: 10.1017/aog.2018.2

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End Users

The sail height data product can be used to improve the characterization of sea ice dynamics in high-resolution sea ice models. It also provides a basis for calibration and validation for sea ice surface elevation measurements collected by various altimetry missions such as the Airborne Topographic Mapper (ATM) laser altimeter, ICESat-2, and Sentinel-3. End users of this sea ice data product include modelers and academia conducting basic research.