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SeaWinds on QuikScat Enhanced Resolution Image Products (version 2)

The wide swath and frequent overflights permit generation of a wide variety of SeaWinds Image products. For highest possible spatial resolution, multiple orbit passes are combined. These are the 'all pass' images. Since generally orbit passes of a given point on the Earth occur at nearly the same time of day, time-of-day studies are facilitated by computing images from ascending (morning) passes only, and descending (evening) passes only. For improved temporal resolution in the polar regions, daily local-time-of-day images have been generated.

Images are made both from the SeaWinds on QuikScat "egg" backscatter measurements and from the "slice" measurements. Generally, slice measurements yield higher spatial resolution but are noiser than egg measurements. The nominal image pixel resolution for egg images is 4.45 km/pixel while the nominal image pixel resolution for slice images is 2.225 km/pixel.

Further information is available in the QuikSCAT Enhanced Resolution Image Users Notes.

Note that these non-enhanced and enhanced spatial resolution sigma-0 images are different than the QuikSCAT Sigma-0 Browse Product images, which are designed only for rapid browsing. (note:large page loads slowly)

Available Image Classes
Egg Images
  H Pol V Pol
all passes+ queh quev
ascending passes only++ qaeh qaev
descending passes only++ qdeh qdev
morning passes* qmeh qmev
mid-day passes** qneh qnev
evening passes*** qeeh qeev
Slice Images
  H Pol V Pol
all passes+ qush qusv
ascending passes only++ qash qasv
descending passes only++ qdsh qdsv
morning passes* qmsh qmsv
mid-day passes** qnsh qnsv
evening passes*** qesh qesv

* Only Ant, Arc, and Grn regions
** Only Ant region
*** Only Arc and Grn regions
+ sea ice masks are in quev and qusv, Ant and Arc
++ non-polar regions only

Images are produced in the BYU .SIR file format using the standard naming scheme. The files are gzipped to minimize storage and transfer requirements. The standard images are designed for land and ice observation. Data over the ocean is generally not useful. However the distributed images are not land masked. .SIR format land mask files (containing 0 for ocean and 1 for land) are available for each standard region. .SIR format images containing "images" of the latitude and longitude of each pixel for each region are also available.
Enhanced resolution image formation algorithm described in D.S. Early and D.G. Long, "Image Reconstruction and Enhanced Resolution Imaging from Irregular Samples," IEEE Transactions on Geoscience and Remote Sensing, Vol. 39, No. 2, pp. 291-302, 2001.
Sea ice extent and sea ice edge derived as described in 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.
Resolution Comparison

NOTE: This page provides access to images processed from the Version 2 QuikSCAT L1B files. JPL switched to Version 2 processing in mid 2006 (JD 189). Due to differences in the processing, the slice location, incidence angles, and calibration, the Version 1 files are slightly different than the Version 2 L1B files. JPL has reprocessed the entire QuikSCAT mission dataset to Version 2 and we have followed suit. Selected mages processed from the old Version 1 data (only for data prior to JD 189, 2006) can be found in the data/qscatv1 directory on the ftp site. This data will eventually be deleted. The file format naming scheme, etc. for SCP images made from Version 1 and Version 2 QuikSCAT files are identical and all utilities, land masks, etc. work the same on both versions. Note, however, that ascending and descending polar images have been discontinued in Version 2, replaced with local time of day images.