To better understand climate change, fifty "Essential Climate Variables (ECV)" are monitored systematically on a global scale. Atmospheric, oceanic and terrestrial variables are covered. METAS supports this work with traceable references.


The aim of the AtmoChemECV project is to provide SI-traceable references with the required uncertainty to detect spacial gradients, shifts and/or long-term trends. Target substances are reactive compounds, in particular those for which reference gas mixtures are not stable in cylinders or at least not at ambient molar fractions. The project focuses on
water vapour at upper tropospheric level ,
fluorinated gases (currently HFC-125, HFC-1234yf, SF6) and
volatile organic compounds (currently α-pinene, butanone or MEK, butenone or MVK, limonene, acetone, ethanol),
and complements the European projects HIGHGAS and KEY-VOCs.

METAS has more than 10 years’ experience in dynamic generation methods, i.e. standards being produced constantly over time, for regulated air pollutants. The project aims at extending these capabilities to very low amount of substance fractions of atmospheric chemical ECVs, which, due to their reactivity cannot be provided in gas cylinders. In order to reduce uncertainties, adsorption/desorption phenomena of reactive compounds on surfaces are minimised.

This project supports and encourages the implementation of such low uncertainty, SI-traceable references in the Global Climate Observing System (GCOS) monitoring network. Thus METAS resp. Switzerland supports the work of the UNFCCC ("United Nations Framework Convention on Climate Change") and the IPCC ("Intergovernmental Panel on Climate Change) and contributes to long-term stable and comparable climate data.


Methods to provide gas standards in situ and/or canisters will be developed in close collaboration with the project partners:
Oeschger Centre for Climate Change Research, University of Bern
Swiss Federal Laboratories for Material Science Technology Empa
Federal Office of Meteorology and Climatology MeteoSwiss

News and Events

SF6 Inter-Comparison Experiment (SICE)

METAS participated in the SF6 Inter-Comparison Experiment (SICE) organised by KMA, Korea Meteorological Administration, World Calibration Centre for SF6 for the GAW (Global Atmosphere Watch) network. This intercomparison exercise took place from April 2016 to February 2017. Results are expected soon.

EGU 2017 conference in Vienna, Austria

Results of the AtmoChemECV project will be presented at the EGU conference in Session AS3.27: "Climate and atmospherically important trace gases: metrology, quality control and measurement comparability".

GAS 2017 conference in Rotterdam

Results will be presented in Session B – Health, safety and the environment.

Popular press article

The dynamic generation of reference gas mixtures for F-gases has been presented in METAS' journal MetInfo (in German).

to the top Last modification 08.03.2017