GSICS Products: Common Reference Channels, Reprocessing, Versions Tim Hewison1 (1) EUMETSAT

Outline of Presentation Introduction To provide background information on recent discussions And steer discussions of these topics in the More to follow in GRWG & GDWG sessions Common Reference Channels Reprocessing GSICS Support for Reprocessing Activities Versions GSICS Products’ Handling of different datasets

GSICS Products: Common Reference Channels The need for Common Reference Channels Potential users for GSICS CRC products Defining Common Reference Channels’ SRFs Development Strategy for GSICS CRC products

GRWG Web Meeting 2010-11-18 To overcome the problem of providing a common reference against which inter-calibration of multiple instrument pairs can be combined, it was proposed that new standard reference channels are defined. These would then be used to generate a new class of GSICS product, which could also be beneficial to some users - e.g. for the generation of composite images from multiple Geostationary imagers with different channels.

GRWG Web Meeting 2010-11-18 It was agreed that potential users should be contacted to solicit their opinion on the usefulness of such a product, and to provide feedback on what combinations of instruments/channels should be considered and at the levels of uncertainty they would require for different applications. It is only then that we can judge whether these are achievable and what level of sophistication is needed to define standard reference channels for these applications. Action: Tim Hewison will pursue these questions with ISCCP, CM-SAF, Earth Radiation Budget and CLARREO.

Potential Users’ Opinions Sought Asked representatives of UTH, CLARREO, ERBE projects Whether they would be interested in a new type of GSICS product: GSICS Conversions to Common Reference Channels For each set of channels common to multiple geostationary imagers e.g. Based on simple rectangular SRFs These would have greater consistency between different instruments, but larger uncertainties due to spectral transformations needed. Could such a product inter-calibrating GEO imagers to “standard reference channels” be useful to you? Which instruments and which channels would you be interested in? And what levels of uncertainty would be needed for such a product to be beneficial to you?

Rémy Roca Laboratoire de Météorologie Dynamique Yes indeed! Up to now we have been dealing with this kind of issue by applying a linear correction, based on radiative transfer computations, to convert all of our Meteosat 6.3 channel into Met-5 equivalent. The choice of  Met-5 is historical. We have shown that such a transfer does not corrupt significantly any of our results. All the Meteosats and maybe other GEO with "water vapor " channel on board. The smallest the better! What can you reach ? I guess for the broad sounding channel like the 6.3. Converting from the original to a common rectangular should not bring in too much noise in the process.

Kurt Thome NASA (GSFC) If I understand the approach you are describing it is very similar to one that I used to help check my ground test data. As you mention, the use of a set of standard bands is limited in a cross-calibration sense, but as you also mention there are benefits such as a clearer assessment of non-sensor related effects on intercalibration. We are effectively creating a similar "product" for the reflected solar instrument on CLARREO. The specific bands that we are going to develop in the reflective are not yet set, and would be selectable. We are, however, being driven towards the MODIS/VIIRS bands.  More specific to your question, I'll leave it to the Daves (Doelling and Young) to speak directly to your questions since it is heavily weighted toward the IR. The basic concept is definitely a good idea, just not sure it is something that needs to be tailored around CLARREO.

Users’ Responses to CRC Great - excellent information. I am curious to see the results... Dr. Marc Schröder (Deutscher Wetterdienst) Satellite Application Facility on Climate Monitoring

Summary of Users’ Feedback on CRCs It is clear that these products would be useful for some applications, although this highlights the fact that different GSICS products may be useful for different applications and clear guidance is needed for users. This topic will be discussed further at the next joint GRWG/GDWG meeting in March 2011. It will also be reviewed at a dedicated web meeting in mid-2011 and at the next GSICS Users' Workshop, which is expected to take place at the EUMETSAT Meteorological Satellite Conference, which will be held in Oslo, Norway in September 2011.

Work Plan to Develop CRC Products GRWG: Define CRC SRFs – This meeting Define uncertainties Develop prototype products Global Composite Images GDWG: Define file format, name conventions Create directories on GSICS Data And Products Servers GCC: Seek feedback from beta-testers Educate Users GPPA

GSICS Products: Support for Re-Analysis Activities

EUMETSAT Re-Analysis of Meteosat Archive EUMETSAT plans to process a re-analysis of whole Meteosat archive Requires development of inter-calibration product using homogenised HIRS data as a reference, [Shi & Bates, 2011] based on GSICS collocation & spectral transformation methods EUMETSAT agreed to draft a detailed work plan for these developments, which Tim Hewison will present this at the next GRWG meeting in March 2011, where it will be reviewed and attempts made to coordinate these activities with related activities of other groups.

Sustained Climate Information Flow Satellite & In Situ Observations Satellite data Environmental Data Records Long-term Information Preservation Fundamental Climate Data Records Interim Thematical Climate Data Records Climate Information Short scale physical phenomena monitoring Operational Climate Monitoring supporting Climate Services Longer term climate variability & climate change analysis Adaptation + mitigation planning (decision making) Sustained Applications Major model-based Reanalysis Short and Medium Latency Re-calibration Inter-calibration Reprocessing Observing system performance Monitoring and automated corrections Data conversion User Services Archived Satellite Data and Sustained Coordinated Processing SCOPE-CM Climate Information Records (CIRs) provide specific information about environmental phenomena of particular importance to science and society (e.g., hurricane trends, drought patterns) The term Fundamental Climate Data Record (FCDR) is used to denote a long-term satellite data record, generally involving a series of instruments (all platforms), with potentially changing measurement approaches, but with overlaps, calibration and quality control sufficient to allow the generation of homogeneous products providing a measure of the intended variable that is accurate and stable enough for climate monitoring. FCDRs include the ancillary data used to calibrate them. For “one-off” research type measurements, the principles do not apply, but as many of the other principles as possible (e.g., those for rigorous instrument characterisation prior and during operations, complementarity of surface and satellite-based observations, etc.) should be followed. The term Product denotes, values of fields of Essential Climate Variables derived from FCDRs. Products may be generated by blending satellite observations and in situ data, or by blending multiple in situ or multiple satellite data sources. Some products are generated within model assimilation schemes. Some satellite-based products are created by using the laws of radiative transfer to retrieve ECVs from the FCDRs. Other documents use the term Thematic Climate Data Record (TCDR) for such products; in the GCOS Implementation Plan , the term Integrated Climate Product was used. The development of products may require strong collaboration between organisations responsible for the generation of datasets (e.g., meteorological services, oceanographic centres, environmental agencies, space agencies) and the separate research or operational groups that generate products, to ensure continuous refinement and extension. Adequate details of the product generation approach need to be documented and made available, along with the products, to ensure repeatability and incremental improvement of the products. For further discussion of the terms Fundamental Climate Records and Thematic Climate Data Records see e.g. National Research Council (2004): Climate Data records from Environmental Satellites, the National Academic press, Washington D.C., USA, 150pp.

METEOSAT 1984-2005 Archive evaluation using radiosondes Upgrade of calibration technique (van de Berg, et al., 95) Upgrade of calibration technique (Schmetz, 1989) ISCCP DX Normalized Instead of nominal Comparisons between the METEOSAT BTs and the simulated BTs from radoisoundings: (+) represent the raw data, (◊) represent the homogeneised data. The histogram shows the nb of soundings used for comparison. Can we do better than that and extend to SEVIRI? Courtesy of Helene Brogniez and Rémy Roca, LMD

Plan for a MVIRI and SEVIRI Infrared Channel Inter-calibrated Data Set within GSICS EUMETSAT proposed within GSICS the inter-calibration of the Meteosat IR channels for the complete series of satellites to arrive at a homogeneous data series that is consistent with HIRS; It will use inter-calibrated HIRS from NOAA/NCDC (adjusted to HIRS on NOAA-12) with GSICS collocation and inter-calibration procedures taking HIRS as truth; Derive CSR, AMV and other parameters from inter-calibrated radiance and document changes with respect to prior reprocessed data; Development and implementation targeted for 2011/2012.

GSICS Products: Versions GSICS Products’ Handling of different datasets

Which version? Originally GSICS products concentrated on Near-Real-Time products Where the versions of the monitored and reference instruments’ datasets are the current operational ones However, we are increasingly supporting Re-Analysis products Where the monitored and reference instruments’ datasets may ultimately be superseded by reprocessed datasets

Handling Multiple Dataset Versions Our products do not explicitly specify which version of the monitored and reference instruments’ datasets they are applicable to This information should be readily identifiable: In the products’ metadata In the products’ filenames? In the directory structure of the Data And Products Server??