Metrology for Climate Sciences: The European Metrology Network for Climate and Ocean Observation
Authors: Woolliams Emma , Fisicaro Paola , Fox Nigel , Pascale Céline , Seitz Steffen , Monte Christian , Werhahn Olav , Gorman David , Dobre Miruna , Damitz Thomas 
Published: March 2020

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&lt;p&gt;Environmental observations of essential climate variables&amp;#160;(ECVs)&amp;#160;and related quantities made by satellites&amp;#160;and&amp;#160;in situ observational networks are used for a wide range of societal applications.&amp;#160;To&amp;#8239;identify&amp;#8239;a small climate trend&amp;#8239;from&amp;#8239;an observational record that is also sensitive to changes in weather,&amp;#8239;to&amp;#8239;seasonal effects&amp;#160;and to&amp;#8239;geophysical processes, it is essential that observations&amp;#160;have a&amp;#160;stable&amp;#160;basis that holds for&amp;#160;multiple decades, whilst&amp;#160;still allowing for changes in the observation instrumentation and operational procedures.&amp;#8239;To achieve this,&amp;#160;all aspects of data collection and handling&amp;#160;must be&amp;#160;underpinned by robust quality assurance.&amp;#160;The resultant data should also be&amp;#160;linked&amp;#160;to a common reference, with well-understood uncertainty analysis, so that observations are interoperable&amp;#8239;and&amp;#8239;coherent; in other words, measurements by different organisations, different instruments and different techniques&amp;#8239;should be able to&amp;#8239;be&amp;#8239;meaningfully&amp;#8239;combined&amp;#8239;and compared.&amp;#8239;&amp;#8239;&amp;#8239;&amp;#160;&lt;/p&gt;
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&lt;p&gt;Metrology, the science of measurement, can provide a critical role in enabling robust, interoperable and stable observational records and can aid users in judging the fitness-for-purpose of such records.&amp;#8239;In addition to Global Climate Observing System (GCOS) monitoring principles, metrology&amp;#8217;s value, and the role of National Metrology Institutes (NMI)&amp;#8239;in observations,&amp;#8239;has been recognised in initiatives such as the Quality Assurance Framework for Earth Observation (QA4EO)&amp;#8239;established&amp;#8239;by the Committee on Earth Observation Satellites (CEOS) and in the implementation plans of the World Meteorological Organization&amp;#8217;s (WMO&amp;#8217;s), Global Atmosphere Watch and the European Ocean Observing System.&amp;#8239;&amp;#160;&lt;/p&gt;
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&lt;p&gt;The European Association for National Metrology Institutes (EURAMET) has recently created the &amp;#8220;European Metrology Network (EMN) for Climate and Ocean Observation&amp;#8221; to support further engagement of the expert communities with metrologists at national metrology insitutes&amp;#8239;and to&amp;#8239;encourage&amp;#8239;Europe&amp;#8217;s metrologists to coordinate their research in response to community needs. The EMN&amp;#8239;has a scope that&amp;#8239;covers metrological support for&amp;#8239;in situ and remote sensing observations&amp;#8239;of atmosphere, land and ocean ECVs&amp;#8239;(and related parameters)&amp;#8239;for climate applications. It also covers the&amp;#8239;additional economic and ecological&amp;#8239;applications of ocean Essential Ocean Variable (EOV)&amp;#8239;observations. It is the European contribution to a global effort to further enhance metrological best practice into such observations&amp;#8239;through targeted research efforts.&amp;#8239;&amp;#160;&lt;/p&gt;
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&lt;p&gt;In late 2019 and early 2020 the EMN carried out a survey to identify the need for metrology within the observational communities and held a webinar workshop to prioritise the identified needs. Here we present the results of the survey and discuss the role that metrology can play in the climate observing system of the future.&amp;#160;&lt;/p&gt;
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