AVIRIS-3 Realtime Data products

These are PRELIMINARY data products generated for rapid response.

Radiance [./radiance]
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Partially calibrated at-sensor radiance, in instrument (unorthorectified) space. 

Radiance data are provided for reproducibility of realtime products only - science analysis should defer to the DAAC-delivered radiances, 
which may included updated wavelengths, flat fields, and radiometric calibration.

Product:

at-sensor radiance, uW nm-1 cm-2 sr-1

Delivered in chunks of 1000 lines at a spatial binning rate of 3 (each output line
is the average of 3 raw frames).

Calibration steps applied: 

  1. dark subtraction
  2. flat field
  3. radiometric calibration coefficients
  4. ghost correction
  
Pedestal shift correction and bad pixel replacement are NOT applied.

284 bands spanning 389.7 - 2493.5 nm at 7.4 nm sampling, stored descending in wavelength.
Files are 32-bit floating point, BIP interleave, ENVI format with accompanying .hdr.

Data are in raw instrument space with no map information. Use the corresponding GLT to
orthorectify.

Location [./loc]
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Per-pixel geographic location, in instrument (unorthorectified) space.

Product:

band 1: longitude (WGS-84, decimal degrees)
band 2: latitude (WGS-84, decimal degrees)
band 3: elevation (m)

Elevations are from a 30 m DEM. Delivered in chunks matching the radiance product, at a binning
rate of 3. Files are 64-bit floating point, BIP interleave, ENVI format with accompanying .hdr.

Data are in raw instrument space with no map information. Use the corresponding GLT to
orthorectify.

Observation Paramter file [./obs]
===================================================================================================
Per-pixel observation and illumination geometry, in instrument (unorthorectified) space.

Product:

band 1: path length (m)
band 2: to-sensor azimuth (0 to 360 degrees cw from N)
band 3: to-sensor zenith (0 to 90 degrees from zenith)
band 4: to-sun azimuth (0 to 360 degrees cw from N)
band 5: to-sun zenith (0 to 90 degrees from zenith)
band 6: solar phase (degrees)
band 7: slope (degrees)
band 8: aspect (degrees)
band 9: cosine(i)
band 10: UTC time (decimal hours)
band 11: earth-sun distance (AU)

Slope, aspect, and cosine(i) are derived from a 30 m DEM. Delivered in chunks matching the
radiance product, at a binning rate of 3. Files are 64-bit floating point, BIP interleave, ENVI
format with accompanying .hdr.

Data are in raw instrument space with no map information. Use the corresponding GLT to
orthorectify.

Geolocation Lookup Table  [./glt]
===================================================================================================
Per-scene lookup table mapping the orthorectified map grid back to raw instrument space.

Product:

band 1: GLT sample lookup (cross-track index into the radiance file)
band 2: GLT line lookup (along-track index into the radiance file)

Values are 1-based indices into the matching radiance chunk; 0 is the no-data value. Negative
values indicate nearest-neighbor infilled pixels, use the absolute value to index.

Orthorectified with a 30 m DEM. Geolocation error is larger over rugged terrain due to the
coarse DEM. Ground sample distance varies from scene to scene. Files are 32-bit integer, BIP
interleave, ENVI format, in WGS 84 / Pseudo-Mercator projection.

To orthorectify, apply the GLT to the radiance chunk of the same name.


Fire Retardant Detection [./fireRetardant]
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This is an EXPERIMENTAL, UNVALIDATED data product under active development. It is provided as-is. 
No guarantee is made as to the accuracy or completeness of the detections. Retardant may be missed
entirely, and spectrally similar surfaces may produce elevated scores.

Product:

  retardant detection score, unitless

Higher values indicate greater likelihood of retardant presence.

Values are relative, not physical units.

Files are mosaics, with all acquisition chunks covering a given flightbox are combined into a single file.

Orthorectified with a 30 m DEM. Geolocation error is larger over rugged terrain due to
the coarse DEM.  Resolution varies from scene to scene.  Files are provided as 32-bit floating point
values, as Cloud Optimized GeoTiffs, in WGS 84 / Pseudo-Mercator projection.

POCs: Adam Chlus (adam.chlus@jpl.nasa.gov)
      Philip Brodrick (philip.brodrick@jpl.nasa.gov)