GSICS Partnerships:
CEOS WGCV IVOS, X-CAL, GRUAN
Tim Hewison1
(1) EUMETSAT
CEOS WGCV
• CEOS WGCV
• Microwave group
• QA4EO guidelines
• Nominated Representatives to attend IVOS & Microwave group meetings
• IVOS group – inter-calibration methodologies, metrology, standards
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Slide: 2
13 July 2017
Good working interactions at the practical level.
However, IVOS are currently updating their written work plan.
It looks like there is some potential overlap between this and the scope of GSICS.
Proposal:
EP prepare statement of how we can best manage cooperation between IVOS+GSICS
(See slides 4-6)
IVOS (CEOS WGCV Infrared and
Visible Optical Sensors subgroup)
Good working relationship on a practical level:
• Many of GSICS’ solar method PIs are active in IVOS
• IVOS seeking collaboration on writing ATBDs for inter-calibrating solar channels
– for example, it may be possible for IVOS to participate in the review process.
• IVOS Wiki to exchange information on 5 methods of calibration for solar-band
channels of moderate resolution sensors:
– Vicarious Calibration System for Earth Observation Optical Sensors (ViCaSEOOS)
• IVOS were also particularly interested in free access to the Instrument Event
Logs, currently being developed by GSICS.
– B. Iacovazzi plans to send out the template and then setup a web meeting.
• CEOS Cal/Val Portal - gives some sensor information
– e.g. spectral response curves, POC for each instrument, etc.
Slide: 3
13 July 2017
IVOS updated written work plan
Mission
The mission of the Infrared and Visible Optical Sensors subgroup is to ensure high quality calibration and
validation of infrared and visible optical data from Earth Observation satellites and validation of
higher-level products.
Terms of Reference
The objectives of the Infrared and Visible Optical Sensors subgroup, beyond those of the WGCV, are to:
• Promote international and national collaboration in the calibration and validation of all infrared and
visible optical sensors and, thus, to assist in the improved application of data from satellite sensors.
• Address all sensors (ground-based, airborne and satellite) for which there is a direct link to the
calibration and validation of satellite sensors. {?}
• Identify and agree on calibration and validation requirements and standard specifications for infrared
and visible optical sensors. {Pre-launch?}
• Identify test sites and encourage continuing observations and intercomparison of data from these
sites.
• Encourage the timely and unencumbered release of data relating to calibration and validation
activities including details of pre-launch and in flight parameters.
• In the context of calibration and validation encourage the full consideration of “traceability” in all
activities involved in the end-to-end development of an EO product including appropriate models and
algorithms. {as CEOS group: emphasise pre-launch work}
Slide: 4
13 July 2017
IVOS updated work plan cont.
Activities and structure (First part…)
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The primary focus of IVOS is to establish an internationally harmonised Cal/Val strategy, including; methods,
Reference standards and infrastructure, to meet the needs of space-based Earth observing system for IVOS relevant
sensors. In particular, to support the development and implementation of GEOSS, the constellations/WGs/and subgroups of CEOS and the needs of other community bodies e.g. GCOS, WMO, IOCCG etc as appropriate.
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This strategy recognises the critical importance of all phases of a satellite mission: pre-flight and post-launch with
the latter including both on-board and vicarious based systems/methods. In developing its strategy, IVOS notes that
although much of the “end-user community” is primarily interested in relatively higher-order products, without a
good understanding of the L1, it is difficult to develop/assess/interpret them. Its work plan therefore places a
strong emphasis on these primary L0/L1 products even if they are not usually distributed. It further recognises that
there are many other existing and active community groups addressing the detailed needs (particularly validation
aspects) of the higher order products, including other CEOS sub-groups, and thus IVOS concentrates its efforts on
supporting activities where radiometric/geometric calibration and/or instrumentation performance/traceability is
of particular importance.
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The work-plan of the last few years and the target for next five, is to work towards establishing a “globally
useable, internationally harmonised, “operational” calibration system (IVOS sensors) under the auspices of CEOS
utilising the combined efforts of member agencies. The objective of this system would be to facilitate
interoperability between sensors at level 1 and subsequent higher level products, enabling all sensor operators to
demonstrate unequivocally and consistently a “quality indicator”, in the context of its application, for their products.
It would readily allow the identification of any “normalisation factors” that may need to be applied to allow
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Slide: 5
13 July 2017
…later mentions working in partnership with GSICS.
GCOS/WCRP
Atmospheric Observation Panel for Climate
(AOPC-XVI)
8.4 Report from CGMS-38
Dr Johannes Schmetz reported on EUMETSAT Climate Activities and on the 38th
meeting of the Coordination Group for Meteorological Satellites (CGMS), held in
New Delhi, India from 8-12 November 2010.
Actions and recommendations:
60. The Panel was pleased to hear the comprehensive report on the CGMS issues.
The Panel recommended that all agencies participating in the Global Spacebased Inter-Calibration System (GSICS) record satellite calibration anomalies and
provide that information online.
…
71. The Panel also raised the potential of radio-occultation measurements to
effectively connect the individual radiosonde stations of the GRUAN; in fact
radio-occultation measurements on satellites could be considered to be a
travelling reference for the upper tropospheric and stratospheric temperatures.
Slide: 6
13 July 2017
GRUAN
• The GRUAN network provides not only high quality radiosondes,
• but is complemented by high quality ground measurements at each site.
• GSICS can provide a service using inter-calibrated satellite data as a
calibration transfer reference to validate radiosonde observations
• The question is what the relationship between GSICS and GRUAN
should be. GRWG came to the following conclusion:
Slide: 7
13 July 2017
No.
Title
Recommendation
GRWG06_02
GSICS sees GRUAN as an important activity. GRWG sees the
primary benefit of GRUAN data to provide validation of GSICS
products on Level 2 products in the framework of groups like
SCOPE-CM and in the framework of CAL-VAL activities. This
will require a 3-way interaction with those groups.
GPM X-CAL
• GPM X-CAL
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Slide: 8
13 July 2017
Inter-calibration of microwave instruments
Conical-scanning imagers
Cross-scanning sounders – temperature and humidity channels
Chris Ruf to represent XCAL in the GSICS Microwave Subgroup
SCOPE-CM
• Need to validate consistency of GSICS Products
• But difficult to directly compare GEO-GEO-LEO
– Because of different channel characteristics
• Apply GSICS Corrections to all GEO imagers
• Use corrected data to retrieve level 2 products
– Need to propagate uncertainties L1->L2
– Compare these in overlap regions to validate GSICS Corrections
• Possible for some GPRCs operating multiple GEOs
• But want global consistency
• Need cooperation with users – e.g. SCOPE-CM
Slide: 9
13 July 2017