GRWG/GDWG Web Meeting 2012-10-31

GSICS Web Meeting on “Follow-up on DCC method, including new MODIS data availability”

Agenda

1. Dave Doelling (NASA) - Introduction to DCC Method and Issues
2. Sebastien Wagner (EUMETSAT) – Implementation of DCC algorithm for SEVIRI at EUMETSAT
3. Sebastien Wagner (EUMETSAT) – Central processing of MODIS DCCs and distrubution within GSICS

Summary

The goal was to settle on a baseline DCC approach, which can be implemented by all GPRCs and decide what data needs to be exchanged to enable this.

To facilitate the development of the baseline approach NASA will provide:

1) The Aqua-MODIS Collection-6 DCC nadir radiance – based on first 3-years of Aqua-MODIS data

2) The SBAF correction factor - based on SCIAMACHY V7.04 footprints over the GEO domain between 2003 and 2010

3) The GEO to Aqua-MODIS 11µm temperature correction factor at 205 K – based on ray-matched GEO and Aqua-MODIS temperature pairs over the lifetime of the GEO record

1. For the FY2C to FY2F series, will need to get access to GSICS corrected image files. Need CMA contact.
2. For COMS, will need to get access to the (4-km) 0.65µm and 11µm image files. Need KMA contact.

4) The exact GEO domain boundaries used in 1), the recommended daily GMT image times, and the Pdel count increment used

5) To provide the HU DCC BRDF model

6) Validation plots that contain for GEOs since 2000

1. Monthly PDFs, based on 4)
2. The monthly gains on a timeline with a linear or quadratic regression

7) To provide the SBAF uncertainty, Jack has provided the Aqua-MODIS absolute calibration uncertainty, and based on future work to derive the DCC calibration transfer uncertainty

EUMETSAT to provide the following:

1) Work with NASA to replicate the GEO DCC implementation of NASA and reproduce almost identical plots. (lets not work on the MODIS part yet)

2) Review IDL code for distribution to other GPRC for implementation

Once EUMETSAT and NASA have similar results:

1) Distribute the code for all other GPRCs

To be resolved in the near future as part of baseline approach:

1) Aqua-MODIS DCC nadir radiance calibration transfer validation

1. Use the apriori Hu BRDF DCC model
2. Use the MODIS empirical BRDF DCC model
3. Validate using ray-matching
4. Start baseline approach with Hu model approach

2) Whether to use visible counts or nominal radiance to base GSICS Calibration/Correction, respectively

And further ahead:

3) Whether to inter-calibrate IR channels’ thresholds dynamically

4) How to tie them to the GSICS reference standard for IR (currently IASI)

NASA to provide the first 3-year of the Aqua-MODIS DCC pixel level radiances in netCDF format to GSICS archive

1) Contact Aleksandar if we can not figure out how to convert binary to monthly GEO netCDF files

2) Use the EUMETSAT ftp site to transfer the monthly GEO netCDF files

3) Have Aleksandar stage the data ~1TB

Discussion on storing and making available intermediate data

Questions raised during the discussion:

1. Need for sharing information on the intermediate steps / dataset?
2. Usefulness for reprocessing activities?
3. Common database/storage for data reference instruments?

EUMETSAT/Pete pointed out to the need of saving such data to ensure traceability but also to the high cost of storing and managing all these data.

However, some reference datasets are fixed in size (e.g. DCCs from MODIS provided by NASA) (comment by EUMETSAT/Tim).

NOAA/Fangfang recalled the request from users to access intermediate data (request formulated at the last user workshop in Sopot, Poland, Sept. 2012)

NOAA/Aleksandar proposed to use the rolling repository as a storage solution (already available on the GSICS servers).

Attendees

NASA: Dave Doelling (lead)

EUMETSAT: Sebastien Wagner, Tim Hewison, Rob Roebeling, Pete Miu, Bartolomeo Viticchie

JMA: Tetsuro Kurita, Yoshihiko Tahara, Hiroaki Tsuchiyama, Kenji Date, Keita Hosaka, Ryuichiro Nakayama, Masaya Takahashi

KMA: Dohyeong Kim, Sunmi Na, Hoseung Lee

NOAA: Fangfang Yu, Teijun Chang, Aleksandar Jelenak

UAH: Dennis Buechler