3.9 and 10.7 um Channel Comparisons
Aside from emissivity and reflectivity, several other factors are responsible for
differences in the appearance of imagery between the 3.9 um and 10.7 um bands:
1), different responses to scene radiance make possible the detection of sub-pixel hot
regions at 3.9 um that are not detected at 10.7 um; 2), the exaggeration of noise at
cold temperatures in the 3.9 um band makes it virtually useless for thunderstorm top
analysis; 3), because of diffraction effects, the 3.9 um and 10.7 um bands view slightly
different areas; and 4), criteria for displaying 3.9 um imagery may differ between day
and night since the 3.9 um band also contains reflected solar energy during the
daytime.
For more in-depth discussion of these differences, please review the following topics:
Temperature Responsivity
Sub-pixel Response
Noise
Diffraction
3.9 um Image Presentation
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