Scatterometer Climate Record Pathfinder
AMSRE Enhanced Resolution Image Product Users Notes
This page is designed as a dynamic
repository of relevant information to aid users of AMSR-E enhanced
resolution image products. Additional information is available here
as a pdf document.
This page is still in development...
Enhanced resolution images made from AMSR data use two
different forms of single-variate the Scatterometer Image
Reconstruction (SIR) algorithm adapted for SSM/I and the AVE algorithm.
Non-enhanced resolution images are produced by gridding data, computing the
mean and STD of all the measurements hitting each grid element, then pixel
replicating the values to the same grid resolution as the SIR or AVE images.
The effective pixel resolution of NON images is 5 grid elements.
For SIR and AVE, multiple passes of the spacecraft are combined to
produce a higher spatial resolution (at a cost of reduced temporal
resolution). Orbits are combined into local-time-of-day images to optimize the
temporal and spatial resolution...
AMSR-E is a six frequency conically scanning radioometer. Each frequency
makes measurements at V and H polarization.
AMSR- data was obtained from AE_L2A.002 data obtained from the National
Snow and Ice Data Center. The non-resample Tb values from this data set were
used with the calibrations provided. The 89 GHz channels were recalibrated.
using the values provided in the NSIDC documentation.
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
Due to its polar orbit, the local-time-of-day of the AMSR observations
varies with latitude and direction of the orbit. At mid- to
low-latitudes, most areas are imaged at two different local
times-of-day -- one for the ascending (north-bound) pass and one for
the descending (south-bound) pass. Thus, by separating the data into
ascending and descending passes, images corresponding to two different
local times-of-day are created. In the polar regions, particular
locations are observed at multiple local times-of-day and so a
different method is required. Local time-of-day is considered in more
detail in a MERS research report
(pdf) on temporal resolution for AMSRE at the poles (pdf).