MODIS Spectral Test.
0.86 reflectance (x-axis) versus the percentage of pixels less then that
value (e.g. cloud fraction if this reflectance was a threshold ) for ocean
scenes solar zenith angles and viewing angle s between 0 - 10 degrees and
30 - 40 degrees. For different viewing geometries, the cloud detection threshold
varies.
![](Vis_threshold_angle.gif) At
low reflectances (less then 10 %) a small change in the threshold can result
in a large change in cloud amount.
![](MODIS_vis_threshold_cloud.gif)
A sensitivity analysis of the MODIS cloud mask to threholds variations similar
to calibration issues. ![](MODIS_bias_thresold_table.gif)
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