The dataset (FSD-GFL-res2m-Preponding) contains sea-ice floe ice distribution (FSD) data derived from the Global Fiducials Library (GFL) imagery during the pre-ponding period at the three fiducial sites, using the algorithms described in Hwang et al. (2017). The GFL imagery is 1-m resolution declassified National Technical Means satellite imagery, also known as the Literal Image Derived Products (LIDPs) (Kwok, 2014). The FSD data derived from the GFL imagery cover the period of 2000 to 2014 at the three fiducial sites at Chukchi Sea (70 deg N and 170 deg W), East Siberian Sea (82 deg N and 150 deg E), and Fram Strait (84.9 deg N and 0.5 deg E). For the production of this dataset, the spatial resolution of the GFL imagery degraded to 2 meters ("res2m") for fast processing. The FSD data are produced for robust model calibration and validation for FSD parameterisations within sea-ice models, and also to improve our understanding of spatial and temporal variations of FSD across the Arctic Ocean. The FSD data have been generated by B. Hwang.
This FSD dataset is produced as part of NERC MIZ NE/R000654/1 (Towards a marginal Arctic sea ice cover).
Arctic, Floe size, Lateral melt, Marginal Ice Zone, Sea ice
Hwang, B. (2020). Sea-ice floe size distribution data derived from USGS GFL high-resolution satellite imagery for the pre-ponding period of 2000-2014 (Version 1.0) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/fca1c981-98dc-4f4f-bbdf-822062df87ac
|Access Constraints:||No restrictions apply.|
|Use Constraints:||This data is supplied under Open Government Licence v3.0 http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/.|
|ISO Topic Categories:||
|Organisation||British Antarctic Survey|
|Role(s)||Technical Contact, Investigator|
|Organisation||University of Huddersfield|
|Reference:||Kwok, R. 2014, Declassified high-resolution visible imagery for Arctic sea ice investigations: An overview. Remote Sensing of Environment, 142(25), 44-56, doi: 10.1016/j.rse.2013.11.015.|
|Quality:||The data quality was checked through manual inspections by the data producer, but the absolute accuracy of the data is unknown due to lack of ground-truth data (see Hwang et al., 2017).|
|Lineage:||The dataset contains the FSD data derived from the GFL imagery at the three fixed locations across the Arctic Ocean. The GFL imagery is 1-m resolution declassified intelligence satellite imagery (National Technical Means), later released to the public by USGS (United States Geological Survey). The imagery data have been obtained from the USGS GFL website. For the production of this dataset, we used the GFL imagery data acquired at the three fiducial sites - Chukchi Sea (70°N and 170°W), East Siberian Sea (82°N and 150°E), and Fram Strait (84.9°N and 0.5°E). The imagery data at the fiducial sites are available as early as 2000 until 2014, providing a long-term collection of the data. This FSD dataset contains the pre-ponding period (i.e., ponding on the ice is not visible in the imagery). Total 41 images were analysed to derive the FSD using the algorithm described in Hwang et al. (2017). The original imagery is available at 1-m resolution but reduced to the 2-m resolution ("res2m") for the FSD retrieval.
The FSD dataset was produced by using the algorithms as described in Hwang et al. (2017), which were implemented in MATLAB.
|Detailed Location||Chukchi Sea|
|Detailed Location||East Siberian Sea|
|Detailed Location||Fram Strait|
|Data Storage:||The FSD dataset is organised in the two folders - FSD_ASCII and FSD_floemap. The folder FSD_ASCII contains the FSD data derived from the GFL imagery in simple text format. The first line in the file contains the size of the GFL imagery in meters from which the FSD data were derived. The second line is the water fraction derived from the imagery. The third line and onward contain floe number and size in meters. The floe size is estimated in mean caliper diameter (Hwang et al. 2017). The folder FSD_floemap contains the imagery files in PNG format, showing the floe boundaries detected by the algorithms in red lines. The data file name is organised to have the short name for the fiducial site, date, id and resolution. Taking the example for chukchi_20060517_1_FSD_res2m.txt, "chuckchi" is the site, "20060517" is the date that the imagery was taken, "1" is the image id, "FSD" stands for floe size distribution, and "res2m" indicates the resolution of the imagery used for the FSD retrieval. The short names for the fiducial sites at Chukchi Sea, East Siberian Sea and Fram Strait are "chukchi", "esiber", "cafram" in the file name.|