Images are made from ERS-1/2 data and use an h(x,y)=Hamming window measurement
spatial response function with the SIR algorithm (a median filter is NOT
used in producing the images). For highest possible spatial resolution,
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. Because the AMI SAR and scatterometer modes are mutually exclusive,
the resulting coverage gaps produce reduced quality images when the SAR
mode is operated over the study area.
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. The noiminal image pixel resolution is 8.9 km/pixel.
Further information is available in the ERS
Enhanced Resolution Image Users Notes.