NCC Status

October 9, 2012

Calvin Liang Stephanie Weiss

NGAS A&DP

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Path Forward to Investigate NCC EDR Issues

• Proposed steps to investigate NCC issue:

1. Collect SVDNB, GDNBO, and IVOBC granules from August 16-17 th, 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

• Completed• In Work• Planned

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Radiance vs Solar Zenith After Stray Light Correction

Noise floor 7e-11

Current SZA cutoff = 105

Straylight removed

Some overcorrection but very little

C. Liang, NGAS

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VNCCO-npp-d20120612-t0012064-e0013407-b03229

For mix solar/lunar conditions, straylight corrected LUT improves image.

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VNCCO-npp-d20120612-t0013301-e0015079-b03229

For mix solar/lunar conditions, straylight corrected LUT improves image.

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VNCCO-npp-d20120612-t0014555-e0016351-b03229

For mix solar/lunar conditions, straylight corrected LUT improves image.

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VNCCO-npp-d20120611-t2357471-e2359320-b03229

For purely lunar conditions, straylight corrected LUT does not improve image

Out of bound values (65528)

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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