GRWG/GDWG Web Meeting 2014-01-08

GSICS Web Meeting on DCC Algorithm Application - Part III

Agenda

1. Masaya Takahashi (JMA) – Comparison of NASA DCC method with JMA RTM simulations
2. Fangfang Yu (NOAA) - Aqua/MODIS Refectance of DCC Pixels over GOES Sub-Regions
3. Dave Doelling (NASA) - Aqua Collection 6 and VIIRS Land PEATE 0.65µm channel DCC calibration results
4. Bertrand Fougnie (CNES) - PARASOL DCC BRDF update
5. Denis Buechler (UAH) - Can DCC Radiance Distributions be Sharpened using Lightning Data?
6. Sebastien Wagner (EUMETSAT) – Analysis of DCCs for MSG2
7. All - DCC Product Definition - format & content
8. All - Discussion on DCC calibration issues for operational implementation & goals for annual meeting

Attendees

Guest Chair: Dave Doelling (NASA)

CMA: Chen Lin

CNES: Bertrand Fougnie

EUMETSAT: Sebastien Wagner, Tim Hewison, Bartolomeo Viticchie, Alessio Lattanzio, Rob Roebeling, Viju John

JMA: Masaya Takahashi, Keita Hosaka

KMA: Minjin Choi

NASA: Dave Doelling, Bob Iacovazzi

NOAA: Fangfang Yu, Manik Bali

UAH: Dennis Buechler

Summary

JMA noted that the NASA DCC and JMA RTM methods MTSAT-2 absolute calibration gains were very similar, although the JMA RTM had twice the standard error about the trend.

NOAA noted that the NOAA desert and DCC methods were very similar in absolute calibration and that all visible calibration methods were consistent. NOAA suggested that the median reduced the monthly DCC variability over the PDF mode method. Need to revisit topic at annual meeting.

NASA presented the stability of Aqua-MODIS and NPP-VIIRS using DCC. Noted that VIIRS instrument is better suited for DCC calibration. Also suggested a method to determine trend significance. Revisit topic at annual meeting when discussing trend uncertainty.

CNES presented the PARASOL DCC BRDF by wavelength. It seems that the backscatter part of the ADM was more isotropic than the forward scatter, especially for higher solar angles. Need to revisit topic at annual meeting.

UAH noted that using lightning to further refine the identification of DCC reduced the number of samples by 93%, however, it did sharpen the peak mainly over land and removed more of the dark tail of the PDF. Might be useful for future imagers

EUMETSAT noted that removing the seasonal cycle, dealing with saturation, and using only ocean improved the DCC method. Using monthly MODIS DCC radiances rather than a constant mitigated the seasonal cycle. Need to revisit topic at annual meeting.

The visible working group then discussed the formulation of the visible calibration netCDF product, of outstanding DCC topics to be discussed at annual meeting, and overall visible calibration methodologies and goals.

EUMETSAT suggested a list of DCC thresholds, reference calibration version, statistics, etc. to include in DCC product file.

EUMETSAT also suggested performing weekly rolling monthly DCC calibration to capture shifts in calibration especially during the early part of the record. Maybe also provide a plot with a temporal trend.

Outcome

Action: NASA to provide the monthly Aqua-MODIS DCC PDF mode radiances over the GEO domains

Action: NASA to provide spectra over clear-ocean and DCC from SCIAMACHY

Action: NASA to provide an article for the GSICS quarterly on trend detection

Action: CNES to provide the PARASOL ADMs to GSICS - Done 2014-01-13 - See BRDF_DCC_PARASOL.7z

As we get closer to the GSICS annual meeting we will be sending out an email for presentation titles.

If anyone has suggestions, or DCC calibration topics, or other visible calibration methods for discussion at the GSICS annual meeting please email Dave Doelling.