AIRS

Frequently Asked Questions


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Q.  What are the surface emissivity values in the Level 2 support product?  

A.  The 39 points from the regression step over land/ice are augmented by
6 points from the final retrieval step for a total of 45 points. Over
ocean, 42 points are used from a model, augmented by 6 points from the
final retrieval step for a total of 48 points.

If you look at regression emissivity output (emisIRInit), you will see
39 points. If you look at final retrieval output (emisIRStd), you will
see 45 points over land and 48 over ocean. You must always match
these points with the frequencies given for that profile (freqEmis)
(there are only 2 sets, one for land/ice and one for ocean).

These points are not to be considered "channels". They represent the
entire spectrum over our range of channels and you should linearly
interpolate between these points to get the emissivity at any spectral
value.

In Version 6, there will be 39 points, always, to simplify this for
users.

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