Traceability Traceability Statement for AIRS/IASI Outstanding Issues with Traceability Concept How we can strive to resolve these Strategy for CLARREO/TRUTHS

Slide: 2 10 October 2014 Traceability Statement for AIRS/IASI A key aspect to GSICS is to provide evidence to support applicability of the inter- calibration products we develop. A document has been prepared collaboratively by GSICS partners at EUMETSAT, NOAA, NIST and CNES to provide a statement demonstrating the suitability of the hyperspectral spectrometers, AIRS and IASI as inter-calibration references. This discusses the various pre-flight and in-orbit tests that have been performed on these instruments. Particular attention is paid to their relative stability, as this is critical if they are to be used inter-changeably. Various method are described which show that AIRS and IASI offer consistent radiometric calibration – each with uncertainties ~0.1K (k=1). The statement also discusses the traceability chain of AIRS and IASI to the SI international reference standards, which is needed to achieve the long-term goal of GSICS. From Article for GSICS Quarterly Statement:

Slide: 3 10 October 2014 Outstanding Issues with Traceability X. Xiong (NASA) to provide Traceability Statement for Aqua/MODIS By End 2011 [Action GRWG06_01] Need Advice on Application of Traceability Concept to Model Results Aircraft instruments Identify experts in traceability issues- NIST and NPL Raise through CEOS/WGCV? May need to revise current Traceability Statements… No.TitleActionee(s)Due Date Action GRWG06_14 Contact NIST and NPL (Raju Datla and Nigel Fox) to define a generic way on how to collaborate on traceability issues T. Hewison30 June 2011

Slide: 4 10 October 2014 Strategy for CLARREO/TRUTHS The US have made the political decision to discontinue the CLARREO concept – But the CLARREO Science Team is still receiving funding. The team is working on a proposal, due on 5 September 2011, to provide a 5 year outlook for a CLARREO-type of instrument on the ISS or an alternative launch platform. – It is likely that this will only cover a limited IR range as a proof of concept. The next decadal survey (2014) may change the situation, – as CLARREO is still a highly recommended mission. TRUTHS is a similar mission, developed by NPL, – but not selected yet as a mission on an ESA spacecraft. GSICS supports proposals for missions such as CLARREO and TRUTHS to provide SI-traceable inter-calibration references in orbit, and invites WMO to communicate this position to the relevant agencies. No.TitleActionee(s)Due Date Action GRWG06_15 Provision of a Statement of Support for TRUTHS by GSICS to Nigel Fox (NPL) J. Lafeuille30 June 2011