GRWG Web Meeting 2020-03-18

VIS/NIR Web Meeting in lieu of annual meeting

Due to the postponement of 2020 GSICS annual meeting and as suggested by the GSICS executive panel, the VIS/NIR GRWG will hold a web meeting on Wednesday March 18, 2020, 11AM UTC.

I decided to hold two meetings in order to accommodate our members across the globe.

For this meeting I want to focus on using on

1) NOAA-20 VIIRS as the GSICS VIS/NIR reference sensor

2) Publishing the GSICS DCC visible calibration, which focuses on agency contributions, this will allow GSICS VIS/NIR products to move forward

Agenda - all times EDT - start time is 11:00 UTC

• 7:00-7:10, Seb Wagner, Lunar conference announcement
• 7:10-7:30, Jason Choi, SNPP and NOAA-20 VIIRS NOAA operational status
• 7:30-7:40, Jack Xiong, NOAA-20 C1 and C2 status (presented by Ning Lei)
• 7:40-7:50 Discussion about making NOAA-20 the VIS/NIR calibration reference
• 7:50-8:10, Yusuke Yogo, DCC VIS/NIR BRDF
• 8:10-8:30, Raj Bhatt, GSICS DCC RSB method referenced to VIIRS (emphasizing SWIR bands)
• 8:30-8:50, Dave Doelling, GSICS DCC agency algorithm paper discussion and agenda for follow on VIS/NIR meeting.
• 8:50-9:00 other discussions

We will also discuss when to hold a GSICS VIS/NIR follow up meeting within a few weeks to allow for presentations not given in this meeting.

The preliminary schedule, let me know if you want to present.

Odele Coddington, LASP, SORCE TSIS solar spectra

Eunkyu Kim, KMA, Gk2A AMI VIS/NIR calibration results

Ling Wang, CMA, Chinese pseudo-invariant calibration sites (CPICS) selection and characterization

Seb Wagner, EUMETSAT, DCC BRDF

Attendees

Guest Chair: Dave Doelling (NASA)

ESA: Stefano Casadio, Marc Bouvet

EUMETSAT: Sebastien Wagner, Tim Hewison (part-time)

JMA: Arata Okuyama, Yusuke Yogo, Masayuki Sasaki, Kazuki Kodera

NASA: Rajendra Bhatt, Ben Scarino, Conor Haney, Jack Xiong, Ning Lei, Amit Angal, Aisheng Wu, Vincent Chang

RAL: Dave Smith

NOAA: Andy Heidinger, Fred Wu, Fangfang Yu, Jason Choi, Likun Wang, Hyelim Yoo, Warren Porter

KMA: Eunkyn Kim, Mingju Gu

CMA: Scott Hu, Na Xu, Lin Chen, Ling Sun, Ling Wang, Chenli Qi, Yuan Li, Hanlie Xu,

USGS: Tom Stone

WMO: Heikki Pohjola, Werner Balogh

Summary

1. Lunar conference announcement - S. Wagner

The 3rd GSICS/IVOS lunar calibration workshop will take place at EUMETSAT between the 16th and 19th of November 2020. There are some delay with respect to the timeline presented in December, but nothing critical. An call for paper will be issued by mid-April. From the participants stand point, two activities are planned: an lunal irradiance model inter-comparison and the definition of a GSICS recommended approach for post-launch MTF assessment. A web meeting is foreseen to be organised in May by NOAA on the MTF topic.

Topic: Status of N-20 VIIRS L1B Collections 1 and 2

Presenter: Ning Lei

Q: Do we expect a C3?

A: Current collection is fairly mature. Monitor for yearly correction, look for degradation. If we stay within 1% then should with current, but will wait on results from lunar monitoring study

Q: (Dave Smith) What work has been done on desert analysis? [Wants to share data over Libya-4]

A: When Collection 2 of SNPP-VIIRS is completely available inter-calibration will be possible. Not using all deserts, but targeting most, like Libya-4. Like MODIS.

Topic: S-NPP and NOAA-20 VIIRS Current Operational Status In Reflective Solar Bands (RSBs)

Presenter: Jason

Q: (Fangfang Yu) How do S-NPP and NOAA-20 VIIRS calibrations compare?

A: Lunar and SD F-factors are very close between SNPP-VIIRS and NOAA-20 VIIRS

Q: How much change in NOAA-20 VIIRS for every band since launch

A: For all bands, about 0.2-0.3%. Gain increasing slightly.

Q: (Andy) This summary of difference would be great for the GSICS user community. Is the DNB part of GSICS management?

A: DNB calibration uncertainty is much larger compared to M-Band and I-Band? Vincent will send Andy and email on calibration differences. Products from the DNB part are different whether from IDPS or NASA

A.GVN.20200318.1: Jason Choi to set up a web page that describes the difference between the NOAA and NASA VIIRS calibration

Topic: Discussion about making NOAA-20 the VIS/NIR calibration reference

Presenter: Dave Doelling

Tom Stone: Lunar conference to make progress of lunar calibration aspect. Needs more work as of now.

Dave Smith: Can tie at least some channels to PICS (e.g., Railroad Valley, RadCalNet Net). Using MODIS and MERRIS as reference and traceability change. CLARREO and other future standards are still a long way off.

Dave Doelling/Dave Smith: We have a way of referencing to MODIS or VIIRS. Many groups do this. We need to ask what instrument is the most stable going forward. Products depend on reference sensor, so it makes sense to have multiple references that different product teams can utilize.

A.GVNIR.20200318.2: Dave Doelling (NASA) to document the expected differences between products that are referenced to difference standards, for VIIRS what is the difference between the NOAA and NASA calibration L1B datasets. Andy mentioned especially for the day night band

A.GVNIR.20200318.3: Dave Doelling (NASA) to set up a web meeting to discuss potential of tying all to one standard (e.g., the Moon).

Topic: Making BRDF for GSICS-DCC with RT Calculation & Voronoi-particle + other related things

Presenter: Yusuke Yogo

Good progress on implementing a DCC BRDF for the SWIR Bands, which is needed.

Great stability in this DCC model.

Topic: DCC characterization and improvements to the calibration algorithm for reflective solar bands

Presenter: Raj Bhatt

Q: (Fred Wu) Have you used G17 or planned to use G17 as a transfer? He was wondering if he was obtaining sufficient DCC sampling.

A: We only did Him-8. Yes GOES-17 is the GEO domain with the least DCC.

Q: (Fangfang Yu) Are the trends seen in G16 statistically significant?

A: Yes, for perhaps 2 bands. For some bands/instrument the trends are not significant given the noise.

Topic: GSICS VIS/NIR DCC Calibration Paper

Presenter: Dave Doelling

A paper with contribution from all agencies on their implementation of the DCC VIS/NIR method

Fangfang Yu/Fred Wu: Agency will fully support the paper. Team working on it already.

Sebastien: Can be working on it for next couple months, in principle. With consideration of ongoing events, however. Paper necessary to settle the method and implementation but need to think about products too. GSICS needs to have operational products to highlight.

Arata Kazuki: Encouraged to include both MTSAT and Himawari series. Will work to offer contributions by mid-summer but will be acquiring a new team member.

KMA:

Scott: Offers to contribute data and will follow-up with an email

A.GVNIR.20200318.4: Dave Doelling (NASA) to send email with table for each agency to fill out. Focusing on GEOs only

A follow-on GSICS VIS/NIR meeting will be planned

1) to give last presenters a chance to talk and

2) discuss difference in NASA/NOAA VIIRS calibration,

3) Dave Smith to discuss his specific use of PICS for calibration.