NCC Status
October 9, 2012
Calvin Liang
Stephanie Weiss
NGAS A&DP
Path Forward to Investigate NCC EDR Issues
• Proposed steps to investigate NCC issue:
2
•Completed
•In Work
•Planned
1.
Collect SVDNB, GDNBO, and IVOBC granules from August 16-17th, 2012 – Around
new moon
2.
Construct stray light correction lookup table (LUT) from new moon data
3.
Apply stray light correction LUT to new moon granules using NGAS stray light
correction algorithm
4.
Determine best functional fit to corrected radiances and account for night glow. (In
work right now)
5.
Produce a new GVVSSE/GVVSLE LUT based on the new functional fits.
6.
Remove stray light in problematic granules
7.
Run the latest version of the NCC EDR algorithm in ADL on stray light corrected
granules (results are shown using ADL 3.1)
8.
Inspect output to determine whether some of the problems identified in the granules
go away with stray light correction
9.
If it is found that fixing stray light does not completely solve the problems, then we
will delve into the NCC EDR algorithm logic
Radiance vs Solar Zenith After Stray Light
Correction
Straylight
removed
Noise floor 7e-11
Some overcorrection
but very little
3
Current SZA cutoff = 105
C. Liang, NGAS
VNCCO-npp-d20120612-t0012064-e0013407-b03229
4
For mix solar/lunar conditions, straylight corrected LUT improves image.
VNCCO-npp-d20120612-t0013301-e0015079-b03229
5
For mix solar/lunar conditions, straylight corrected LUT improves image.
VNCCO-npp-d20120612-t0014555-e0016351-b03229
6
For mix solar/lunar conditions, straylight corrected LUT improves image.
VNCCO-npp-d20120611-t2357471-e2359320-b03229
Out of bound values (65528)
7
For purely lunar conditions, straylight corrected LUT does not improve image
Summary
• For mixed solar and lunar conditions, i.e. when lunar and solar angles
are between 0 and 105, the stray light corrected LUT seems to
improve the contrast in images
• The application of the straylight corrected NCC table does not seem to
fix the problem of NCC producing an abundance of “out of bound”
values
• Will likely need to delve into the code to investigate this further
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