ET-SAT-V1/Doc. 2 EXPERT-TEAM ON SATELLITE SYSTEMS (ET-SAT) First Virtual Meeting (WEBEX, Tuesday 21 January 2014, 11:00 – 14:00 UTC

FCDRS FOR THE ARCHITECTURE FOR CLIMATE MONITORING FROM SPACE

1. Scope of the discussion

One expected outcome of ET-SAT is to advise WMO on the definition and implementation of the Architecture for Climate Monitoring from Space, following the “Strategy towards an Architecture for Climate Monitoring from Space” jointly drafted by CEOS, CGMS and WMO.

Satellite operators adhering to the “CGMS Baseline” are committing to sustain a number of missions that, for many of them, can support climate monitoring. The virtual meeting will focus on how to take advantage of these long-term commitments as building blocks for the definition of the Architecture, and in particular how to facilitate CGMS Action 41.43.

2. Outcome of ET-SAT-8 discussion on the Architecture

ET-SAT-8 discussed the Architecture (ET-SAT-8 Final Report, Item 5, pages 7-8). It was recalled that the ECV Product Inventory was designed for ECV product data sets, or “Thematic Climate Data Records” (TCDRs). Such an inventory at the product level is useful to assess the data quality and the adequacy of the end-to-end data processing chain. ET-SAT-8 felt, however, that remaining at the “product” level may not be the most appropriate to inform on long-term mission planning and foreseeable gaps in data acquisition.

Two main reasons were mentioned:

- Many satellite missions can support the generation of several ECVs (e.g. IR imagery supports Cloud properties, Sea Surface Temperature, Vegetation, etc) and reciprocally some ECVs can be supported by various types of missions ((e.g. Upper-Air Temperature by IR sounding, MW sounding, Radio-occultation, etc). Thus there is no one-to-one correspondence between satellite missions and ECVs. Identifying gaps in ECV products does not directly inform on satellite mission gaps.

- Satellite and payload characteristics are planned years in advance of the launch. Although agencies strive to plan the whole product chains in advance too, the products are not always defined with sufficient details to be captured in the inventory that many years ahead. The generation of climate products also involves different communities. The result is that, as of July 2013, the ECV Product inventory was mainly focused on past or current missions, rather than future missions. This is a strong limitation as the aim of the Architecture is to provide guidance for future missions.

It was therefore noted in the ET-SAT-8 report:

- “There is value in registering not only the ECV product datasets, i.e. Thematic Climate Data Records (TCDRs) but also the Fundamental Climate Data Records (FCDRs), which are in principle excluded from the ECV inventory. Indeed, some FCDRs can support several TCDRs (e.g. “Microwave radiances”, etc). A minor extension of the ECV product inventory is thus suggested in this respect.

1 ET-SAT-V1/Doc. 2 It is clear, however, that the very broad definition of the mission categories in the CGMS baseline is not sufficient to characterize their ability to support ECV product generation. This requires a categorization based on more precise criteria (…)

3. CGMS-41 discussion and action

As agreed at ET-SAT, these findings were reported to CGMS-41 (Tsukuba, 8-12 July 2013). CGMS supported these views. EUMETSAT also made a statement in the same sense. The CGMS-41 Final Report includes the following words (highlighted here by WMO):

“As a contribution to the architecture, WMO provided a mapping of the satellite missions foreseen in the CGMS baseline to the essential climate variables (ECVs) product inventory. This showed that these missions supported a large part of the datasets recorded in the inventory. Moreover, these missions had the potential to provide Fundamental Climate Data Records (FCDRs) that were important for climate monitoring but were not properly captured in the ECV product inventory. (…)

From the discussion which followed the presentation, it was recommended to extend the ECV product inventory to include FCDRs. It was also acknowledged that the CGMS baseline has a prospective dimension which is of high value for the climate monitoring architecture, but often too generic to inform on FCDRs. WMO therefore suggested that a finer categorisation of CGMS baseline missions should be used to draw a list of sustained FCDRs coordinated by CGMS. It also proposed that the design phase of new sensors should include analysis of compatibility with heritage sensors. These points were taken up by CGMS and it was agreed that they were important for future planning.

During the discussion, EUMETSAT emphasised the need to identify FCDRs that CGMS members can commit to provide on a sustained basis and to identify the CGMS priorities and where there is complementarity with CEOS. Members agreed that the current focus is on how agencies can produce the FCDRs, but in the future the inventory should also help users. Once the FCDRs are captured with tracebility to missions, instruments and possibly the ECVs, the issue of how to ensure interaction with users shall be addressed.

CGMS then assigned the following action to its Working Group III :

Action 41.43: WG III Members to define a first list of FCDRs that CGMS Members can commit to provide on a sustained basis as a contribution to the architecture for climate monitoring from space, building on the CGMS baseline, and to communicate this contribution to the future CEOS-CGMS working group on climate. (Due: 15 Feb 2014).

4. Proposed role of ET-SAT

ET-SAT has been instrumental in formulating the CGMS baseline in 2011. Since it has raised the need to refer to the FCDRs, this team is anticipated to be in a good position to guide CGMS WGIII Members on developing this list of FCDRs, to be derived from the CGMS baseline.

The ET-SAT discussion aims to: - facilitate a common understanding of Action 41.43 by the satellite operators, - provide guidance to fulfill the action in the most meaningful way, - for example, develop a template with a controlled list of FCDRs, helping the agencies to provide their inputs in a consistent way that can be easily consolidated.

2 ET-SAT-V1/Doc. 2 The outcome of this exercise is needed in January, enabling the CGMS Members to complete Action 41.43 by mid-February, as an input to the joint CEOS-CGMS WG on climate that will convene in Darmstadt on 5-7 March 2014.

5. Relationship between CGMS baseline, FCDRs and ECVs

As an illustration, the table below provides a few examples of the relationship between: - the ECVs (as defined by GCOS), - potentially relevant missions (as defined in the CGMS baseline) - specific features needed to ensure that these missions are actually relevant for the ECV - tentative description of the corresponding FCDRs.

The last two columns have been tentatively populated by the WMO Secretariat as an example.

ECV Potentially relevant Additional required Relevant FCDRs (as defined by missions (as defined by features GCOS) the CGMS Baseline ) (Tentative) (Tentative)

Sea Surface LEO/ Multispectral Include split-window LEO IR radiances Temperature VIS/IR imagery channels e.g.10 and 12 including split 10- µm imagery 12 µm Sea Surface LEO/ MW imagery, Low Frequency MW radiances in Temperature some polarimetric channels 5-10 GHz the 5-10 GHz range Ocean Surface LEO/ Polarimetric LEO Full polarisation needed MW radiances over Wind speed and MW imagery sea with full direction polarisation Ocean Surface LEO/ Scatterometers Radar-scatterometer C-Band or X-band Wind speed and around 5 GHz (C) or 11 Backscatter cross- direction GHz (X) section over sea

Upper air LEO/ IR hyper-spectral Includes CO2 bands (4.3 IR spectra temperature sounders m or 15 m)

Upper air LEO/ MW sounders Include O2 bands (54 or MW temperature temperature 118 GHz) sounder radiances (incl 54/118 GHz) Upper air LEO/ Radio-occultation GNSS signal temperature bending angles Ocean colour Narrow-band Vis/NIR Include specifically VIS reflectance in imagers (ocean colour narrow-band VIS ocean narrow-band ocean and vegetation) colour channels (e.g. colour channels 442.5 nm, 490 nm, 560 nm, 665 nm, 681.25 nm)

6. References

- (Draft) CIMO Guide on Satellite Observation, chapter 5 ftp://ftp.wmo.int/dept/sat/documents/cimo/CIMO-guide-IV-V8-Chapter-5.pdf - OSCAR/space : http://www.wmo.int/oscar/space - CGMS baseline for operational missions contributing to the GOS http://www.wmo.int/pages/prog/sat/meetings/documents/ET-SAT-7_Inf_02_Baseline.pdf

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