Preliminary After-launch GOCI Characterization: Inter-slot radiance discrepancy issue Young-Je Park*, Hee-Jeong Han, Seongick Cho, Joo-Hyung Ryu, Jae-Hyun Ahn and Yu-Whan Ahn Korea Ocean Satellite Center, Korea Ocean Research and Development Institute Presented at IGARSS 2011, Vancouver, Canada
Preliminary After-launch GOCI Characterization: Inter-slot radiance discrepancy issue. Young-Je Park*, Hee-Jeong Han, Seongick Cho, Joo-Hyung Ryu , Jae-Hyun Ahn and Yu- Whan Ahn Korea Ocean Satellite Center, Korea Ocean Research and Development Institute - PowerPoint PPT Presentation
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Korea Ocean Satellite Center, Korea Ocean Research and Development Institute
Presented at IGARSS 2011, Vancouver, Canada
Objectives
• To understand the inter-slot radiance discrepancy issue
• To seek ideas/suggestions on how to approach this GOCI specific issue
Sensors have specific issues
• MODIS stripe noise– detector calibration– difference in mirror side characteristics– Sensitivity to polarization state
• MERIS– SMILE effects: wavelength variation – Discontinuity at some camera interface
Outline
• Overview of the GOCI optical system and image acquisition sequence
• Inter-slot discrepancy: – variability within a slot– variability across different slot boundaries– variability with observation hours (0, 3, 7 hours)– How RT simulations show
• Distance-to-border weighted average– Applied to overlapped area– Simple and good for image generation– Smoothing the TOA reflectance data will not be
good for downstream data processing including the atmospheric correction.
– Smoothing the geophysical parameters would make sense.
Distance-to-border weighted average
d1
Slot i
d2
d3
d4
Slot i
wi
wi = min(d1,d2,d3,d4) where is number of pixels to the k-th border
Slot j
wj
N’=∑(wi Nⅹ i)/∑wi
N’: weighted averageNi: reading from the ith slot
Example 1 (original)GOCI 20110412-07h, South Japan
Example 1 (weighted average)GOCI 20110412-07h, South Japan
Future work
• Clarify questions of – Is it an issue of the GOCI radiometric calibration?– Is it an issue of the band filter properties?– Is it an issue of the ghost image?
• Develop a scientifically based model to correct the inter-slot discrepancy. Bands6,7,8 are critical for atmospheric correction.
Thank you!
Please contact us if you have any idea on this issue.