Second FRM4SOC Workshop on Calibration and Characterisation of Ocean Colour Field Radiometers

20 – 22 May 2025,      
Tartu Observatory, University of Tartu, Estonia

Background

The quality of the satellite Ocean Colour (OC) data products and user services relies on the quality of in situ radiometric measurements used in algorithm development and product validations. Space-borne instruments must be accurately calibrated and characterised before launch, monitored while in space, and additionally vicarious calibrated. Calibration and characterisation activities are also performed on field radiometers so that the community can depend on the validation and the algorithms that define the performance of satellite missions.

Fiducial Reference Measurements (FRM) are a suite of independent, fully characterised, and metrologically traceable ground measurements that follow the guidelines outlined by the Quality Assurance Framework for Earth Observation (QA4EO) of the Committee on Earth Observation Satellites. In this context, ESA (2016-2019) and EUMETSAT (2021-present) conducted a series of FRM4SOC (Fiducial Reference Measurements for Satellite Ocean Colour) projects with the overarching goal of promoting the adoption of the FRM standards in Ocean Colour. These FRM standards include a series of requirements on radiometers to ensure documented traceability to SI units via an unbroken chain of calibrations, the assessment of instrument-related uncertainties and a series of recommended characterisations.

To achieve this goal, the FRM4SOC-2 project team focuses on several tasks

  1. Provide practical guidelines and procedures for calibration, characterisation, use of radiometric instruments, best practices in the field, and how to derive the uncertainty budget of the acquired measurements.
  2. Provide tools to process radiometric field measurements with associated uncertainties (e.g. HyperCP) and databases to store results of calibrations (e.g. FidRadDB) and field measurements(e.g. OCDB).
  3. Test what is being implemented, achieved by means of laboratory and field inter-comparison experiments.
  4. Broadcast the guidelines and tools to the OC community. This is mainly achieved through workshops and training events.

Objectives of the workshop

Calibration and characterisation of in situ Ocean Colour Radiometers (OCR) is an important part of ensuring the FRM quality of field measurements for the validation of satellite data. An addendum to IOCCG Protocols Volume 3: Satellite Ocean Color Data Validation: In situ Optical Radiometry was proposed by FRM4SOC to raise awareness to OCR manufacturers on key elements needed to ensure a critical mass of OCR users achieving FRM-quality field measurements.

The main objective of the workshop is to reach out to all interested parties working on the calibration and characterisation of OCR (manufacturers, metrology institutes, calibration laboratories, FRMOCnet development teams) and discuss the following topics:

  • present and future challenges in calibration and characterisation of OCR, e.g.
    • calibration and characterisation principles, facilities, and methods,
    • data acquisition, processing, and formats,
    • evaluation of uncertainties for different calibration equipment, measurement conditions and methods,
    • development of metrology-sound as well as operationally-achievable uncertainty budgets,
  • the requirements to achieve FRM quality of in situ measurements for satellite data validation (need for calibration and characterisation of OCR),
  • existing guidelines, procedures, tools, and best laboratory practices for OCR calibration and characterisation,
  • organisation of future comparison measurements,
  • knowledge exchange on the methods, procedures and facilities,
  • visit to the calibration and characterisation laboratories at Tartu Observatory of the University of Tartu,
  • improvement and harmonisation of the developed guidelines, procedures and tools.

Tentative agenda

Tuesday, 20 May 2025  
8:30 Bus from Tartu to Tõravere  
9:00 – 13:00 Workshop Session 1  
13:00 – 14:00 Lunch  
14:00 – 18:00 Workshop Session 2  
18:00 Bus from Tõravere to Tartu

Wednesday, 21 May 2025  
8:30 Bus from Tartu to Tõravere  
9:00 – 13:00 Workshop Session 3  
13:00 – 14:00 Lunch  
14:00 – 18:00 Workshop Session 4  
18:00 Bus from Tõravere to Tartu  
19:00 Workshop dinner in Tartu

Thursday, 22 May 2025  
8:30 Bus from Tartu to Tõravere  
9:00 – 13:00 Workshop Session 5  
13:00 – End of the workshop  

 

Venue

Tartu Observatory          
University of Tartu          
Observatooriumi 1,          
Tõravere EE-61602          
Tartu county          
Estonia

Travel info

We recommend to stay in Tartu at

A shuttle bus will be arranged to take you from Tartu centre to Tartu Observatory at Tõravere and back (Bus pick-up point).

Directions to reach Tartu Observatory.

Travel support

Some participants can be provided with limited financial support for travel tickets and accommodation. 

Contact

Riho Vendt          
Associate professor          
Tartu Observatory University of Tartu          
Observatooriumi 1,          
EE-61602 Tõravere,          
Estonia          
riho.vendt@ut.ee