IR hyperspectral comparisons Presented by Denis Jouglet (denis.jouglet@cnes.fr) GSICS annual meeting 2016, JAXA, Tsukuba, Japan

Discussion about IASI-A end of life operations Discussion about IASI non-linearity tables update Future inter-comparison to TANSO-FTS/2

IASI-A end of life operations After the IASI-C cal/val (mid 2019), IASI-A should decommissioned  Opportunity to propose specific end of life operations! For calibration and inter-calibration, the following ideas have been proposed and are under assessment (joint work by CNES & EUMETSAT): IASI-A to keep the same local time at ascending node but with a slightly lower altitude Would provide numerous real Simultaneous Nadir Observations with IASI-B and IASI-C, even over a short period of time Requires resources (manoeuvers) IASI-A, B and C to make simultaneous lunar observations, without any satellite rotation (Cold Space 2 Target) Would provide TIR hyperspectral spectra of the Moon Would assess the use of lunar inter-calibration in the TIR Any comment from GSICS? Any suggestion? If interested, support from GSICS could help to motivate the request

IASI non-linearity tables update IASI inter-comparisons show a small bias in IASI B1 A residual default of the analog non-linearity correction in B1 of at least one IASI is a possible explanation Non-linearity is corrected in the IASI interferograms by on board processing, with pre-computed correction tables (cannot be corrected by a simple scaling). Studies performed at CNES to try to diagnose the impact of non-linearity residuals The conclusion is likely to update the tables There is no possibility to re-process the former data (interferograms are not downloaded on ground)  Changing the table makes a small gap in the calibration Question for GSICS: Which one is better? Implement this correction on-board : improves absolute calibration but breaks the radiometric stability Stay with the current tuning Provide an estimated a posteriori correction (with error bars) Illustration of impact : Mean radiometric error between without and with operational non-linearity correction

Future inter-comparison to TANSO-FTS 2 GOSAT-2 is planned for the end 2017 TANSO-FTS / GOSAT-2 has a broad TIR band Will fly at the same period as IASI-A, IASI-B, IASI-C, CrIS, AIRS?, others? The local time at ascending node provides SNOs with all other missions Does NIES or JAXA plan an inter-comparison at level 1? Does GSICS plan such inter-comparison? From Matsunaga et al., June 2015, IWGGMS-11