1. Recommendations to GSICS from international working groups GSICS meeting, March 2016, Tsukuba, Japan
Rob Roebeling
Hi Masaya,
My question is that whether we have time to discuss on the review items in the GPPA or not (e.g., review of robustness of uploading products).
This is not on the agenda at the moment, but is a good question. Can you discuss in GDWG under GPPA?
I'm also interested in the MVIRI inter-calibration. Will you inter-calibrate MVIRI before 2006? Today, I had a chat with Toshi on the annual meeting. He told me "At 2014 EP-15 meeting, EP members discussed who should define/guide the inter-calibration methods for the past instruments. At that time we did not get consensus, but you should discuss this issue at the annual meeting". In the following are my questions on re-calibration and inter-calibration for past instruments. Hope we can discuss those issues next week (Hidehiko can join this discussion).
I will not do MVIRI before IASI (2007). That is the job of our colleagues in USC.
- Should GSICS define (or stamp) the inter-calibration method for the past instruments (e.g., SCOPE-CM/IOGEO method using HIRS for IR/WV inter-calibration)?
But the question of defining inter-calibration methods for past instruments is an important one. I hope Rob will be able to address it in his discussion on “Requirements for NRTC/RAC/ARC”.
- Do you have any plan to inter-calibrate Meteosat-7/MVIRI before 2006 using HIRS (or will you use AIRS between 2003 and 2006?) ?
Yes – Viju has been working on this within USC – using AIRS to bridge the gap between older HIRS/2 instruments (which have SRFs similar to MVIRI) and IASI.
- Do you have any idea to tie multiple calibration methods together in order to produce GSICS Prime Correction (e.g., using delta correction) ?
Yes – see discussions on “Combining algorithms: DCC+Lunar” and “Prime GSICS Corrections”.
- Who should inter-calibrate all the channels of past instruments? For example, IOGEO project will inter-calibrate focusing on VIS/WV/IR (11um) channels (not SWIR and 12um).
Within EUMETSAT, USC. We will ask other agencies after Rob’s discussion on ARC/RAC.
Rob: please add a slide to ask!
- Should we move existing GSICS Corrections to operational phase even though a satellite will be end of the life soon? For example, MTSAT-1R will retire in this year. Is JMA responsible for updating the phase of MTSAT-1R GEO-LEO-IR products even if we cannot move them to operational phase by the end of this year? I think this issue is related to Archive Re-Calibration product, and my opinion is "yes, we should generate re-calibration product for archiving purpose. This is one of the GSICS strategies(?)".
Another good question for the same discussion. I say “yes”, but I am doing “no”!

2. Outline Introduction Requirements- Near Real-Time
Committee for Earth Observation Satellites (CEOS-CGMS)
EUMETSATs Data Record Generation Working Group
CGMS science working groups (e.g. ICWG, IPWG)
NRTC/RAC/ARC
For example, I suggested he discussed with you the "Requirements for NRTC/RAC/ARC". As you know at present we generate Near-Real-Time-Corrections and Re-Analysis Corrections for GEO-LEO IR, based on single pairs of instruments (one monitored, one reference). I would like you to consider what the requirements could be a GSICS Archive Re-Calibration, which is the sort of thing you are doing in SCOPE-CM. E.g. Could these requirements be met by my proposed Prime GSICS Corrections? i.e. Merging together inter-calibration results from different reference instruments, after correcting them to a common datum (the "Primary Reference") using "delta Corrections" (the double-difference of their time series).

3. Fundamental Climate Data Records (FCDR) discussion (1)
The user community is split in opinion on the required type of re-calibration coefficients for FCDRs, which are either:
Sensor equivalent calibration: refers to the calibration where each sensor is calibrated in such a way that the spectral characteristics of that individual sensor are maintained. As a result of this process, the calibrated radiances represent the unique nature (e.g., spectral response function) of the monitored sensor.
Reference sensor normalised calibration: refers to the calibration that provides the best match to spectral characteristics of a predefined “reference*” sensor. As a result of this process, the calibrated radiances represent the unique nature (e.g., spectral response function) of the “reference” sensor. The normalised calibration includes information on uncertainty associated with adjusting the characteristics of the monitored sensor to those of the predefined “reference” sensor.
NRTC/RAC/ARC
For example, I suggested he discussed with you the "Requirements for NRTC/RAC/ARC". As you know at present we generate Near-Real-Time-Corrections and Re-Analysis Corrections for GEO-LEO IR, based on single pairs of instruments (one monitored, one reference). I would like you to consider what the requirements could be a GSICS Archive Re-Calibration, which is the sort of thing you are doing in SCOPE-CM. E.g. Could these requirements be met by my proposed Prime GSICS Corrections? i.e. Merging together inter-calibration results from different reference instruments, after correcting them to a common datum (the "Primary Reference") using "delta Corrections" (the double-difference of their time series). 3

4. Fundamental Climate Data Records (FCDR) discussion (2)
Blue arrows show the aim of
Re-calibration, Sensor Equivalent Calibration or Harmonization
Sensor 1
Sensor X
Time
Radiances
Calibration as it should be
Actual Calibration
Note, sensor equivalent calibrations as supposed to differ in radiances (or counts) due to differences in sensor characteristics
NRTC/RAC/ARC
For example, I suggested he discussed with you the "Requirements for NRTC/RAC/ARC". As you know at present we generate Near-Real-Time-Corrections and Re-Analysis Corrections for GEO-LEO IR, based on single pairs of instruments (one monitored, one reference). I would like you to consider what the requirements could be a GSICS Archive Re-Calibration, which is the sort of thing you are doing in SCOPE-CM. E.g. Could these requirements be met by my proposed Prime GSICS Corrections? i.e. Merging together inter-calibration results from different reference instruments, after correcting them to a common datum (the "Primary Reference") using "delta Corrections" (the double-difference of their time series). 4

5. Fundamental Climate Data Records (FCDR) discussion (3)
Blue arrows show the aim of Inter-calibration, Reference Sensor Normalized Calibration, or Homogenization
Sensor 1
Reference Sensor used for normalization
A sensor from the series or a hypothetical sensor
Sensor X
Radiances
Correct or True Calibration
Reference Sensor Normalized Calibration
Time
Uncertainty due to differences between
the characteristics of the reference sensor and
the characteristics of the other sensors in the series
NRTC/RAC/ARC
For example, I suggested he discussed with you the "Requirements for NRTC/RAC/ARC". As you know at present we generate Near-Real-Time-Corrections and Re-Analysis Corrections for GEO-LEO IR, based on single pairs of instruments (one monitored, one reference). I would like you to consider what the requirements could be a GSICS Archive Re-Calibration, which is the sort of thing you are doing in SCOPE-CM. E.g. Could these requirements be met by my proposed Prime GSICS Corrections? i.e. Merging together inter-calibration results from different reference instruments, after correcting them to a common datum (the "Primary Reference") using "delta Corrections" (the double-difference of their time series). 5

6. Fundamental Climate Data Records (FCDR) discussion (4)
To satisfy the split opinion of the user community, FCDRs should preferably provide three data representations that are internally convertible, i.e.:
Raw counts › original counts and associated auxiliary data/measurements
Absolute radiances conversions › the best individual estimate for each sensor
Relative radiances conversions › spectral band adjustment factors to convert radiances of the monitored to radiances of a reference sensor.
NRTC/RAC/ARC
For example, I suggested he discussed with you the "Requirements for NRTC/RAC/ARC". As you know at present we generate Near-Real-Time-Corrections and Re-Analysis Corrections for GEO-LEO IR, based on single pairs of instruments (one monitored, one reference). I would like you to consider what the requirements could be a GSICS Archive Re-Calibration, which is the sort of thing you are doing in SCOPE-CM. E.g. Could these requirements be met by my proposed Prime GSICS Corrections? i.e. Merging together inter-calibration results from different reference instruments, after correcting them to a common datum (the "Primary Reference") using "delta Corrections" (the double-difference of their time series). 6

7. Requirements to GSICS - Near Real-Time -
Objectives NRT: The NRT community uses re-calibrated radiances Nowcasting purposes and for assimilation into Numerical Weather Prediction (NWP) or re-analysis models. Requirement: Near-real time calibration information shall be available with a timeliness better than 5 minutes after image reception; Requirement: Quantitative information on the instrument spectral response function used for the absolute (re)calibration shall be made available with the near-real-time data; Requirement: Preference for absolute re-calibration rather than relative re-calibration (NWP and Nowcasting community); Requirement: Preference for re-calibrated radiances (better than 2%) including uncertainty estimate information (NWP community). Requirement: Re-calibrated radiances shall be provided in common file formats (e.g. BUFR, NetCDF) using internationally agreed metadata standards.
Disclaimer: Based on requirements of re-analysis activity in ERACLIM
Contact Adrian Simmons and Paul Poli and Dick Dee

8. Requirements to GSICS - Committee for Earth Observation Satellites (CEOS-CGMS) -
Objectives CGMS-CEOS: to establish an inventory of existing records of Essential Climate Variables derived from space observations, to plan the production of more CDRs and to optimize planning of future satellites to expand records and avoid data gaps. Requirement: re-calibrated time-series shoud include past/present/future instruments; Requirement: re-calibrated data from multiple instruments should be verified on consistency in overlapping regions and/or during overlapping observation periods; Requirement: time-series of re-calibrated radiances shall be regularly evaluated on temporal stability, step changes, degration, etc; Requirment: re-calibrated data should be provided with information on random errors and time-dependent biases; Requirement: re-calibrated data should be provided in common file formats (e.g. BUFR, NetCDF) using internationally agreed metadata standard.
Note: CGMS-CEOS requirements are tied and reference to spatial, temporal, accuracy, and stability GCOS 2010 implementation plan (GCOS-138) and satellite supplement (GCOS-154), and the GCOS guidelines for data sets (GCOS-143). 
Courtesy John Bates and Pascal Lecomte
Dear Rob,
thanks for your interest and for contacting me.  Pascal and I are currently working on assessment and gap analysis reference processes for the ECV inventory.  For that work, our requirements come from GCOS, in particular the GCOS 2010 implementation plan (GCOS-138) and satellite supplement (GCOS-154), and the GCOS guidelines for data sets (GCOS-143).  As we have begun to perform the assessment and gap analysis, we have found that we must tie to and reference all the elements of these to specific requirements (spatial, temporal, accuracy, and stability from GCOS-154; guidelines and principles from GCOS-143.  So, and requirements you suggest, must be identified and reference against a particular GCOS one.  I'm providing an Excel sheet that we are using that provides the cross references for each question of the ECV inventory projected on to the 4 pillars of the climate monitoring architecture (numbered PILLARS 1-4), GCOS data set guidelines (numbered NEEDS 1-12 from table in GCOS-143) and GCOS climate monitoring principles (GCMP numbered 1-20).  It is quite important that we trace all requirements this way.
In your suggested requirements, you have some that can be traced this way and others that exceed GCOS or have no reference.  For example, your first statement is traceable to NEEDS 1, 2, etc. as well as CGMP 14 and 15.  However, there is no GCOS requirement uncertainty on the individual pixel level as per your item 2, so we should not use this.
So, even though it may seem that the GCOS requirements are a bit less that you may like or a bit too general, we must use only the GCOS ones and assess compliance against only those.  It turns out we still have a long way to go even to achieve these and so we should not identify others that are not yet vetted and adopted by GCOS.
Attached are an Excel spreadsheet of the ECV inventory questions and the mapping of those against the GCOS.  You may add ones for calibration, but only when referenced against a specific GCOS #.
I hope you appreciate why we need this type of approach.  We would like to have all providers of FCDRs to be able to answer and comply with these questions in the ECV inventory.  We need to keep a focus on this.
Regards, John

9. Requirements to GSICS - EUMETSAT’s Data Record Generation Working Group (DRG-WG) -
Objectives DRG-WG: to coordinate reprocessing activities of the Satellite Application Facilities (SAFs) and the EUMETSAT Secretariat; to discuss strategies, potential for synergies and mechanism for co-operations; to address technical reprocessing aspects. Recommendation: DRG-WG asks for FCDRs from passive imagers and microwave sounders from past/present/future missions; Recommendation: DRG-WG encourages availability of asked FCDRs before the start of the SAFs Continued Development and Operational Phase-3 (CDOP-3) in 2018; Requirement: re-calibrated data shall included absolute re-calibation corrections, as well as inter-satellite conversion coefficients including uncertainty estimates; Requirement: re-calibrated radiances shall be evaluated on spatial uniformity and spatial accuracy of the uncertainty estimates. Especially when data records is based on multiple missions and systematic viewing geometry variations.
Note: Draft requirements based on personal communication with DRG-WG co-chairs (R. Hollemann and K. Holmlund) and secretary (R. Roebeling)

10. Recommendations to GSICS - International Clouds Working Group -
Recommendation: ICWG acknowledges GSICS’s efforts to calibrate infrared (IR) and water vapour (WV) channels, and recommends cloud product providers of to use the IR and WV recalibrations from GSICS for their quantitative retrievals from passive imagers. Recommendation: ICWG confirms the need for accurate calibration of the visible (VIS) and near-infrared (NIR) channels of passive images (2-3%), and stresses the importance of providing these calibrations for the current and the heritage instruments (e.g. MVIRI, SEVIRI, AVHRR, MODIS, VISSR, IMAGER, VIIRS..).
Courtesy Bryan Baum and Rob Roebeling (ICWG co-chairs)

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