Images are made from the Seasat Scatterometer Geophysical Record data
files and use an h(x,y)=0/1 measurement spatial response function with
the SIRF algorithm. For highest possible spatial resolution as well as
to ensure full coverage over the images, multiple orbit passes are combined.
These are the 'all pass' images. Generally orbit passes of a given point
on the Earth occur at nearly the same time of day. Unlike later scatterometers
the operating mode of SASS was changed very frequently over land. Only
a limited amount of H-pol data was collected over land and ice during
the mission. The limited spatial coverage requires rather long imaging
time periods but there are still frequent gaps in the image coverage.
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 and so are
landmasked. However, .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.
Further information is available in the SASS
Enhanced Resolution Image Users Notes.