Craig Donlon (Sentinel-3 Mission Scientist) P. Goryl - Head of SPPA section P. Femenias, S. Dransfield – Data Quality Managers
Fiducial Reference Measurements (FRM)
Outline
– Context – in particular Sentinel-3
– What are FRM? – Examples (mainly under
Sentinel-3) – Summary and conclusions
What is Copernicus? – Space in Action for You!
• A source of information for policymakers, industry, scientists, business and the public
• A European response to global issues:
• manage the environment;
• understand and to mitigate the effects of climate change;
• ensure civil security
• A user-driven programme of services for environment and security
• An integrated Earth Observation system (combining space-based and in-situ data with Earth System Models)
The importance of validation and verification - example of Sentinel-3
– Sentinel cost ~ Hundreds of Millions (450MEuro for S3 A/B) – Each payload instrument is an accurate and precise scientific
instrument – Maintaining quality is all about a regular stream of verification
and validation data that can be used to check mission and product performance
– Verification and validation data shall be of an equal and ideally a better quality than anything else
– We cannot do this without fundamental traceability and uncertainty budgets for all ground measurements used
– Why should we validate Sentinel-3 with substandard data?
S3A
S3B
S3C
S3D
S2A
S2B
S2C&D
In Europe, we have a lot of Copernicus Satellite infrastructure in preparation – will we be able demonstrate
its performance?
Can we demonstrate we have met requirements?
Are products “fit for purpose” within Copernicus?
Fiducial Reference Measurements (FRM)
– fi·du·cial (adj) Regarded or employed as a standard of reference, as in surveying.
– [Late Latin fdcilis, from Latin fdcia, trust, from fdere, to trust; seebheidh- in Indo-European roots.]
– What’s wrong with in situ? – It means everything to the uneducated – It’s not tangible to a funding agency – It is not precise enough to argue for a validation
program
– Sentinel-3 FRM are: – Linked to the S3 Cal/Val plan activities – Based on specific requirements – Forward thinking – long-term vision – Building on the existing capability – Have an inclusive approach: FRM are not Mission specific (e.g. S3A, B, C,
D… S2A, B, C, D…all need ocean colour FRM…, All Altimeters need transponders for range calibration – and Sigma0…)
Why do we need FRM?
– FRM are the suite of independent ground measurements that provide the maximum scientific utility/return on investment for a satellite mission by delivering, to users, the required confidence in data products, in the form of independent validation results and satellite measurement uncertainty estimation, over the duration of the mission (Donlon et al, 2014)
– IF we have no FRM then we cannot really use the mission as we have no idea how accurate data products are
– IF we have many FRM this is great scientifically (statistical significance, geographic coverage, robust network…) but incurs additional costs with reducing ROI
We refer to Fiducial Reference Measurements
(FRM)
NOT simply in situ data.
Is a mission product “fit for purpose”? It depends our knowledge of how “good” it is…
(Donlon et al, 2014, in ”Optical Radiometry for Oceans and Climate”)
Sentinel Validation Team – ex: S3VT setting
– The Sentinel Mission Performance Centre (MPCs) are designed to conduct operational verification and validation, quality control and end-to-end mission performance assessment activities e.g for S3.
– SST using DBCP/ARGO drifters – OC using AERONET-OC/moorings – Topography using tide gauges/transponders
– The Sentinel Validation Team is designed to conduct scientific experiments and Independent analyses to provide independent FRM validation evidence:
example for S3 – SST/OC: ship-borne radiometers – OC: in water radiometers
– The SVT complements the MPC - but is not the same – SVT focus is FRM
Validation Implementation Plan – example of S3VT Implementation Plan
– The S3VT Implementation Plan (S3VT-IP) is be the main reference for S3VT activities
– The S3VT-IP provides a “Dossier” of all the activities currently approved by the joint ESA-EUMETSAT rolling AO call for S3VT Activities.
– Will be used by other entities within the Sentinel-3 Mission during Phase E1 and E2 for planning and coordination
– Thank you for your inputs! – “Living document” - funding/people/plans all change – One-stop shop to look up “who is doing what” – Important statement of European and International validation
groups relevant to S3 and provides a formal relationship with ESA/EUMETSAT
ESA FRM pilot projects
– Preparing ground truth radiometers and drifting buoy as FRM (SI Traceability)
– Preparing above water radiometers and vicarious infrastructure in Europe for Ocean Colour FRM (SI Traceability)
– Procedures and approached to maintain ground transponders with SI Traceability)
– Collection of marine FRM for S3 SLSTR and OLCI, S2 MSI and S1 C-band SAR http://amt4sentinelfrm.org
http://www.frm4sts.org/
https://frm4soc.org
http://www.frm4alt.eu/
ESA pilot projects dedicated to atmosphere domain
FRM4GHG – started - The focus of the “Fiducial Reference Measurements for Ground-Based FTIR Greenhouse Gas Observations” (FRM4GHG) project is the intercomparison of instruments and harmonization of products and retrievals from ground based FTIR systems
FRM4DOAS – started – The “FRM for Ground-Based DOAS Air-Quality Observations” (FRM4DOAS) project aims at the harmonization of the retrievals from UV-Visible ground based spectrometers, e.g., MAXDOAS or Pandora, in view of reaching the standards of FRMs for NO2 and ozone.
Poster: – Fiducial Reference Measurements for Ground-Based DOAS Air-Quality Observations, Van
Roozendael, Michel; Hendrick, Francois; Gielen, Clio; Friess, Udo; Kreher, Karin; Piters, Ankie; Richter, Andreas; Wagner, Thomas
– Fiducial Reference Measurements for Ground-Based Infrared Greenhouse Gas Observations (FRM4GHG) at the Sodankylä TCCON site, Sha, Mahesh Kumar; De Mazière, Martine; Notholt, Justus; Chen, Huilin; Griffith, David; Hase, Frank; Kivi, Rigel; Weidmann, Damien
FRM4 projects – generic organisation
Laboratory Laboratory Calibration Exercise (LCE) SI traceability Necessary for all participants to assess biases to SI under Laboratory conditions Field Field Inter- comparison Calibration Exercise (FICE) Analysis Analysis Discussion, Workshop Publications
Working Group on Calibration and Validation
FRM4STS: Fiducial Reference measurements for validation of Surface Temperature from Satellites (ceos cv8)
Nigel Fox
NPL (ESA Project)
WGCV Plenary # 40
Overview of project
15
Aim: to establish and maintain SI traceability of global Fiducial Reference Measurements (FRM) for satellite derived surface temperature product validation and help develop a case for their long term sustainability Requires:
•Comparisons to ensure consistency between measurement teams
•Accessible common descriptions and evaluation of uncertainties
•Robust links to SI
•Experiments to evaluate sources of bias/uncertainty under differing operational conditions
•International community buy-in (customer and supplier) of added value and how to achieve – through provision of guidance and best practises and access to standards and comparisons
Context: CEOS plenary (2014) endorsed a project to carry out a series of comparisons of instrumentation & methods used to validate satellite IR measurements of surface (Ocean, Land) Temp to ensure international harmonisation
( (an extension of previous ‘Miami series’)
ESA FRM4STS Inter-comparison @NPL London June 2016
ESA FRM4STS Inter-comparison @NPL London June 2016
FICE (LST) – May - June 2017 • Currently 5 participants
• MORE WELCOMED REGISTER @ Website • Delayed to allow participants time between LCE • Led by KIT (experienced with site) • Range of targets (Gravel, Sand)
• Assess means of determining emissivity • Use towers and vehicle based transects • First comparison of this nature (will establish international
state-of-the-art in such measurements) • Comparisons made using pre-defined protocol following
metrological best practise • Full uncertainty evaluations by participants • All results & metadata published on FRM4ST.org website
(allows updates and long term record of evidence)
Ice Temp comparison • April 16 (pilot for future!) • 3 participants • Results being analysed
To establish and maintain SI traceability of Fiducial Reference Measurements (FRM) for satellite ocean colour (QA4EO/FRM4SOC) Web: https://frm4soc.org Contact: [email protected]
OBJ-1: Design and implement a laboratory-based comparison of the calibration processes for FRM OC radiometers OBJ-2: Design and implement a laboratory-based comparison to verify reference radiance sources used to maintain calibration of FRM OC radiometers. OBJ-3: Design and implement field inter-comparisons using pairs of FRM OC radiometers to build a database of knowledge over a several years. OBJ-4: Conduct field-campaigns for FRM OC validation in collaboration with CEOS and the international community. OBJ-5: Conduct a full data analysis, derivation and specification of uncertainties, following agreed NMI protocols on all data collected as part of FRM4-SOC. OBJ-7: Publish all outcomes and results in an open and transparent manner using peer reviewed and other grey literature. OBJ-8: Evaluate and cost options and approaches to the long term vicarious calibration and verification of the Sentinel- OLCI & MSI A/B/C and D instruments.
FM4ALT
– Establish and demonstrate SI traceability of Fiducial Reference Measurements (FRM) and their use for satellite derived altimeter calibration and validation.
– OBJ-1: Develop and approach, document and demonstrate (by traceability to SI units) how measurements used for satellite altimeter calibration and validation acquired by instruments at PACF attain Fiducial Reference Measurement status as defined in section 1.
– OBJ-2: Design, document and demonstrate procedures to operate the PACF facility for satellite altimeter calibration and validation activities and maintain FRM status.
– OBJ-3: Conduct a full data analysis, derivation and specification of uncertainty budgets, following agreed NMI protocols, for all measurements made at the PACF facility for satellite altimeter calibration and validation.
– OBJ-4: Document necessary changes at PACF to ensure that the site maintains FRM status. [The implementation of any changes shall be in agreement with ESA.]
– OBJ-5: Design, Implement and report altimeter calibration and validation experiments using the PACF site for relevant satellite altimeters (ie. Jason-2, Jason-3, AltiKa, CryoSat2, Sentinel-3A and possibly Sentinel-3B).
– OBJ-6: Demonstrate how the PACF activity contributes to the Global multi-technique satellite altimeter calibration and validation approach.
Web: http://amt4sentinelfrm.org/Home Contact: Gavin Tilstone [email protected]
FRM applies to all measurements used for validation activities
Summary
– The concept of Fiducial Reference Measurements is fundamental and a core element of the validation IP
– This means demonstrating traceability to SI units for ground measurement's used to validate EO products
– Satellite instruments are being traced to the same SI units
– Please use the FRM thinking and terminology!
