QuikSCAT Ice Extent Products
Selected QuikSCAT Ice Extent Products are now available. Additional
products will be posted as they are available. We note that a Near-Real-Time
(NRT) version of the algorithm is run on QuikSCAT data as part of
the wind processing to mask out sea ice regions.
The QuikSCAT sea ice extent algorithm is based on an modification
of the NSCAT algorithm. The estimated extent of sea ice is estimated
for each Ant and Arc regional image for both slices and eggs. The
polarization ratio (AV-AH in dB), incidence angle dependence
(B images), and the sigma-0 estimate error standard deviation
(V images) are used to perform the sea ice/ocean discrimination.
Residual misclassification noise is reduced using binary image processing
techniques such as region growing, erosion, and dilation resulting
in a low pass filtered version of the sea ice extent edge. The resulting
edge closely matches the NSIDC SSM/I-derived 30% ice concentration
edge.
The sea ice extent product is in two forms: a masked image generated
by applying the binary extent mask to the V-pol, A-image
(.imsk file) and an ASCII edge file (.ie file). The lat/lon values
in the ASCII edge files were obtained by computing the lat/lon location
of each pixel along the edge of the binary ice mask. Ice extent
products are included in the V-pol, ascending/descending, A
image directories of the Antarctic (Ant) and Arctic (Arc) regions
for eggs (quev) and slices (qusv).
Masked V-pol files (.imsk): Masked
V-pol, A image of quev and qusv images of Antarctica (Ant)
and the(Arc). Ocean areas outside of the estimated sea ice extent
are set to the no-data value.
IE files (.ie): ASCII files containing
latitude/longitude pairs which represent the contour points of the
estimated sea ice edge. Each line entry in the file consists of
two values: a longitude and a lattitude. The longitude values range
from -180 to +180. Multiple contours are separated by a '0 0' entry.
Reduced size sample masked image product
References:
Q.D. Remund and D.G. Long, "A Decade of QuikSCAT Scatterometer Sea Ice Extent Data," IEEE Transactions on Geoscience and Remote Sensing, doi:10.1109/TGRS.2013.2281056, Vol. 52. No. 7, pp. 4281-4290, 2014.
Q.P. Remund and D.G. Long, "Iterative Estimation
of Antarctic Sea Ice Extent Using Seawinds Data," Proceedings
of the International
Geoscience and Remote Sensing Symposium, pp. 491-493, Hilton
Hawaiian Village, Honolulu, Hawaii, 24-28 July 2000.
Q.P. Remund and D.G. Long, "Sea Ice Extent Mapping
Using Ku-Band Scatterometer Data," Journal of Geophysical
Research, Vol. 104, No. C5, pp. 11515-11527, 1999.
Q.P. Remund and D.G. Long, "Sea Ice Mapping Algorithm
for QuikSCAT and Seawinds," Proceedings of the International
Geoscience and Remote Sensing Symposium, pp. 1686-1688, Seattle,
Washington, 6-10 July, 1998.
Related References:
H.S. Anderson and D.G. Long, "Sea Ice Mapping Method f
or SeaWinds,"
IEEE Transactions on Geoscience and Remote Sensing,
Vol. 43, No. 3, pp. 647-657, 2005.
J. Haarpainter, R.T. Tonboe, D.G. Long and M. L. VanWoert,
"Automatic Detection and Validity of the Sea Ice Edge: An Application
of Enhanced Resolution QuikScat/SeaWinds Data,"
IEEE Transactions on Geoscience and Remote Sensing,
Vol. 42, No. 7, pp. 1433-1443, 2004.
J. Haarpaintner, "Arctic-Wide Operational Sea Ice
Drift From Enhanced-Resolution QuikSCAT/SeaWinds Scatterometry and Its
Validation," IEEE Transactions on Geoscience and Remote Sensing,
Vol. 44, No. 1, pp. 102-107, 2006.
J. Haarpainter and G. Spreen, "Use of Enhanced-Resolution
QuikSCAT/SeaWinds Data for Operational Ice Services and Climate Research:
Sea Ice Edge, Type, Concentration, and Drift,"
IEEE Transactions on Geoscience and Remote Sensing,
Vol. 45, No. 10, pp. 3131-3137, 2007.
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