MetEOC-4

Metrology to Establish an SI Traceable Climate Observing System (MetEOC-4)

Overview

The Earth’s climate is changing. The scale of impact to future society remains uncertain and with it government’s ability to confidently take necessary mitigation/adaptation in a timely manner. A key limitation is the performance of forecast models and the quality of the data that drive them. Remote sensing from space is the major means of obtaining the global data needed.

The harshness of launch and environment of space severely limits accuracy and traceability. This project will improve pre-and post-launch calibration/validation (Cal/Val) of observations (land, ocean and atmosphere) to enable trustable information on the state-of-the planet to be delivered to policy makers.

The Need

Two thirds of the Essential Climate Variables (ECV) of the Global Climate Observing System (GCOS) rely on optical measurements. More than half must be measured from space. Improving traceability and accuracy of these data is at the top-of-the-agenda of space agencies. In many cases a factor of 10 improvement in measurement accuracy is required to optimally minimise the time to detect trends from natural variability.

Climate forecast is based on models using empirical ground and space based data. Ground based is mainly local data whereas space observations deliver a global picture. The uncertainty of the empirical data determines the trustworthiness of the climate forecast. Reducing the uncertainty of this data is therefore considered mandatory. Achieving this reduction in uncertainty, places an urgency to address the following challenges:

• Maximal use of satellite observational capacity to globally detect small signals without driving cost. This requires improved (efficiency and accuracy) of pre-flight calibration and validation methods that are rigorously traceable to the SI.
• Improved confidence in multi-decadal time-series of observations and ‘on demand’ delivery of data requires post-launch interoperability between different sensors. Since the performance of most sensors changes in-orbit this requires improved SI traceable post-launch calibration, validation and harmonisation methods including networks of ‘ideally’ autonomous test sites of a range of parameters.
• Policy makers and commercial users require trustable long time-base climate information – metrologically based quality metrics assigned to bio-geophysical parameters
• Some climate parameters cannot be measured from space. Global representation requires networks of sensors tied to common international standards. Historical artefact based standards need to be replaced/enhanced through improved linkage to SI to ensure long-term reliability.

Improvement necessitates evolution of laboratory-based metrology transferred to field (and space) situations.

The MetEOC series of projects continues to address the overriding traceability issue through undertaking new case studies as well as extending previous activities. Many space related projects can take a decade or more from conception to realisation, and this is similarly reflected in the timelines needed to prove and implement technological changes, where the innovation first needs to be proven in the laboratory before adaptation and migration to the field.

Project Objectives

The overall goal of this project is to build on the outputs of previous projects (EMRP/EMPIR and others funded by the EU and European Space Station (ESA) for example) to create the metrology tools and framework needed to underpin a global climate observing system. The scale of the challenge is vast, and this project will focus efforts on topics described in the following objectives, selected to capitalise on synergy with other international initiatives, prioritised to address needs of forthcoming European climate focused sensors and related ECVs.

• To develop a robust metrological chain (infrastructure and methods) to trace to the SI a new generation of highly accurate, cost-effective sensors, for a space-based climate observing system, suitable for pre- and in-flight measurements, prioritising the needs emerging from current mission studies.
• To develop SI traceable measurement methods with associated uncertainties for bio-geophysical parameters at pixel level and accounting for scene specific characteristics including the means to optimally parameterise, validate and assess the uncertainties of retrieval algorithms. This will consider harmonisation of sampling methods including optical and SAR based techniques.
• To develop satellite derived SI traceable measurement methods (including uncertainty assessment, associated validation and interoperability) for greenhouse gases emissions and natural carbon sinks, including robust monitoring of implemented policies to reduce the anthropogenic carbon emission (in accordance with the Paris Agreement of 2015 and Vienna 2018).
• To develop instrumentation and standards for traceable climate quality measurements, including temperature of the Mesopause and thermal infrared sky radiance, from surface-based networks such as those operated under the WMO and UN e.g. NDMC.
• To facilitate the take up of the technology and measurement infrastructure developed in the project by the measurement supply chain (accredited laboratories, instrument manufacturers), standards developing organisations and end users (environmental monitoring and regulation bodies such as the WMO and Group of Earth Observations (GEO).

Project Details

Project Name: Metrology to Establish an SI Traceable Climate Observing System (MetEOC-4)
EURAMET Project Number: 19ENV07
Start date: 1 Sep. 2020
Duration: 36 months
Project coordinator: Prof. Nigel Fox
National Physical Laboratory, England

MetEOC-4 Partners

Aalto (Finland), CMI (Czech Republic), NPL (United Kingdom), PMOD/WRC (Switzerland), PTB (Germany)

Links

MetEOC Website

EURAMET MetEOC-4 Website

Funding kindly received from EMPIR