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Rainer Hollmann Deutscher Wetterdienst

Rainer Hollmann Deutscher Wetterdienst. Cloud cci. Overview of talk. Overview of requirements Product specifications Uncertainties Consistency with needs of climate Research Group consistency with other ECVs (ECMWF data needs … are documented in DARD).

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Rainer Hollmann Deutscher Wetterdienst

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  1. Rainer Hollmann Deutscher Wetterdienst Cloud cci

  2. Overview of talk • Overview of requirements • Product specifications • Uncertainties • Consistency with needs of climate Research Group • consistency with other ECVs • (ECMWF data needs … are documented in DARD)

  3. URD: compilation of requirements from the users point of view covering ideally the full spectrum of applications Product specification: The answer to the URD what is achievable and feasible and how it is designed User requirements

  4. Kent et al (2008): “The definition of user requirements for the marine observing system is not a simple process. When asked, users have a tendency to ask "what can you provide?" or reply "as much as possible“ Cloud User requirements based on GCOS CMUG EPS-SG, MTG, CM SAF WMO DOR, Database of observational requirements ESA CCI Variables Globsnow (a few days ago) User Requirements

  5. GCOS requirements for clouds Requirements as stated in GCOS-107, product A-4, update 2011 Requirements as stated in GCOS-107, product A-4:

  6. Cloud Properties requirementsfrom CCI variables (I)

  7. Cloud Properties requirementsfrom CCI variables (II)

  8. Cloud Properties requirementsfrom CCI variables (III)

  9. Consistency with needs of Climate Research Group • Cloud CCI URD is reflecting all important Req. • has been forwarded to open review of science community (GEWEX RP) • Needs of Cloud CCI Climate Research are included.

  10. Consistency with other CCI‘s • Cloud CCI provided URD to all CCI SC for feeback • received positive feedback from Aerosols, Land Cover, SST, Fire • needs are documented in URD covering different time periods and instruments • Most likely cloud CCI will not be able to cover all additional requirements • Evaluation process ongoing

  11. CCI URD addresses the GCOS need for FCDR for all instruments CCI Cloud is performing Level 1 Intercalibration for AVHRR-AATSR-MODIS instruments CCI Variables based on same instruments should agree on the same FCDRs! Consistency on Level 1 Radiances

  12. Current baseline: Specifications • Temporal resolution of final products • (based on local satellite equator crossing time) • AATSR/MERIS (ENVISAT): • 10:00 am/pm • AVHRR (N15, N16, N17, N18): • 10.00 am/pm (drifting), 02:00 am/pm (drifting), 10:00 am/pm, 01.30 am/pm • MODIS (AQUA,TERRA): • 01:30 am/pm, 10:30 am/pm • Providing the final products: • Monthly means for each individual sensor • Monthly means for each sensor group (e.g. all AVHRRs) • Monthly means for all sensors on all satellites • AATSR-MODIS-AVHRR • AATSR-MERIS

  13. Current baseline: Specifications (I)

  14. Current baseline: Specifications (II)

  15. Product compliance (I)

  16. Product compliance (II)

  17. Product compliance (III) • Summary on compliance for Cloud CCI: • Specification meet the GCOS 107 Requirements • Further discussion on requirements from CMUG with TO & SC needed • Joint work on cloud simulator approach • Identifying case studies to supply full inst. data for process studies • …

  18. Focus on Level 2 uncertainties Reference data will be A-Train data and high quality surface networks Possibly include threshold limit to allow filtering of model data Started process of evaluation of Level 2 to Level 3 uncertainties supported by international science community (CREW, GEWEX Cloud Assessment) Aiming at radiative consistency on Level 3 Uncertainties

  19. Non Systematic errors: Retrieval error: Uncertainty estimation of the retrieval system itself based on optimal estimation methodology. Sampling error: Due to the sampling of temporally and spatially unequally distributed samples. Systematic errors (bias) Radiometric Bias: calibration issue Retrieval Bias: Biases related to shortcomings in a retrieval itself. Sampling/Contextual Bias: Biases related to where a retrieval is/is not performed or contextually related uncertainty in a scene. Aggregation/Data Reduction Bias: Loss of required information during conversion to a gridded product or during analysis. Other considerations Cognitive Bias ? Correlated error "Independent" products that share similar biases; Tautology -Circular reasoning or treating non-independent data as independent during tuning. Error uncertainties Level 2

  20. Cloud CCI requirements from ECMWF (I)

  21. Cloud CCI requirements from ECMWF (II)

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