|The wide swath and frequent overflights permit generation of a wide variety
of OSCAT Image products. The similarity of QuikSCAT and OSCAT means that OSCAT can be viewed
as a continuity mission for QuikSCAT. (Note, however, that OSCAT measurements are at a
slightly different incidence angle, which produces different sigma-0 values. No incidence angle correction is applied in OSCAT SCP version 0 images.)
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 OSCAT footprint ("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 OSCAT
Enhanced Resolution Image Users Notes.
The OSCAT SIR and AVE images are produced from OSCAT Level-1B (L1B) products produced by ISRO. The L1B files available from ISRO were produced using several different software versions. These reflect improving calibrations, but there are inconsistencies between versions.
|JD 309, 2009 - JD 015, 2010||1.2|
|JD 016, 2010 - JD 181, 2010||1.3|
|JD 182, 2010 - JD 273, 2010||no data|
|JD 274, 2010 - JD 147, 2013||1.3|
|JD 148, 2013 - Present||1.4|
At present the SCP is not making corrections to the L1B files to correct inconsistencies
between the versions of the L1B processor. Users shoud take care when using images that
span boundaries between procesor versions.
As reprocessed L1B data becomes available, current SCP products will be updated with the most recent version available.
Available Image Classes
* Only Ant region
** Only Arc, Grn, and NHe regions
*** Only Ant, Arc, Grn, and NHe regions
+ sea ice masks are in ouev and ousv, Ant and Arc
++ non-polar regions only