The Metrology for Meteorology Conference: MMC 2014

During the last years, the worldwide interaction between the metrology and meteorology communities has grown and improved. An increasing exchange of mutual membership and participation in expert teams, task groups and commissions of international institutions is contributing to enforce this liaison. Metrologists are now sitting as members in the expert teams of the Commission for Instruments and Methods of Observations (CIMO) of the World Meteorological Organization (WMO) and in its Commission for Climatology (CCl) Open Panel of Experts (OPACEs); staff from National Institutes of Metrology (NMIs) have membership in the International Surface Temperature Initiative and in the Global Climate Observing System (GCOS) Reference Upper Air Network (GRUAN); the interaction between chemical metrology and the Global Atmospheric Watch (GAW) is growing from practical technical activities in laboratories up to the Consultative Committee for Amount of Substance, Metrology in Chemistry and Biology sessions of the International Committee for Weights and Measures (CIPM). Scientific supervisors, coming from the metrology community, also support projects on climate and atmospheric observations field. At the same time, key metrology institutions such as EURAMET, the European Association of National Institutes of Metrology (NMIs) and the CIPM Consultative Committee in Thermometry, launched a new task group on environment, to address the metrology needs arising from the meteorology and climate communities towards recommendations and funded joint research projects. Those new task groups host experts in climate and meteorological sciences as well, as full members. These collaborations have changed deeply the way several laboratories in the NMIs operate. A new generation of metrologists is now prepared to respond to the needs of different scientific communities. Meteorology, climate and environmental metrology are among the emerging new fields based on the long-lasting scientific experience achieved in the previous decades by NMIs. The development of new devices, calibration procedures, guidelines, in situ operations and measurement campaigns are part of the metrology research work for physicists, chemists, engineers and biologists working in close cooperation with meteorologists, climatologists and environmental scientists. Since 2010, EURAMET, through its European Metrology Research Programme (EMRP), is funding several projects aimed at delivering results of valuable impact for the meteorology and climatology sciences. The key aspect of these projects is to establish traceability of measurements and uncertainties of measured physical and chemical quantities describing the Earth atmosphere. One of those projects, MeteoMet (Metrology for Meteorology), in addition to the planned tasks and deliverables, has established a robust collaboration among its stakeholders. The success in making those collaborations a real and practical further outcome of the project, allowed MeteoMet to be awarded the EURAMET ‘Impact Prize’ in 2013. Among the several dissemination activities of MeteoMet, the consortium launched in 2012 the idea of an internal conference to provide a framework for networking and collaborating among the various stakeholders. The organization quickly surpassed the joint research project internal event status, to become a place for discussing collaborations and activities, for projects being addressed and prepared, for points of view being exchanged, roadmaps drafted and common visions planned. After the WMO-BIPM Workshop on Measurement Challenges for Global Observation Systems for Climate Change Monitoring held in 2010 in Geneva, Switzerland, the Metrology for Meteorology and Climate 2014 (MMC 2014), in Brdo, Slovenia, has been the main international event organized with the specific aim to stimulate a fruitful exchange of information among those two disciplines (Figure 1). The conference emphasized the great opportunity provided by putting together many of the world experts on the relevant aspects of mathematics, physics, chemistry, biology, metrology, meteorology, climatology and environmental science. The number and relevance of international institutions having endorsed and co-sponsored MMC 2014 clearly vouch for this trend, together with the scientific value of the contributions that many authors submitted, collected and presented here as a book of abstracts. The conference hosted numerous participants and satellites events at the modern conference centre of Brdo, Slovenia, few minutes from the Ljubljana airport in the historical, beautiful natural heritage centre of the Brdo Castle. During the 3 days, MMC covered several topics organized in parallel sessions: traceability and uncertainty in weather measurements; ground-based systems; upper air measurements and aircraft-based measurements; sensors and their dynamics; quantities of influence and mutual influences; ocean research; water: water vapour, liquid water, ice, hygrometry, soil moisture; rain and snow gauges; permafrost temperature measurements; instruments, procedures and calibrations; best practice and regulations; assessment of historical temperature measurement data with respect to uncertainties on instruments used. A ceremony for rewarding a young Nepalese Researcher, Deependra Das Mulmi, for his contribution in bringing calibration facilities to the Everest Pyramid was also organized. The 120 international participants presented 70 talks and 35 posters which were organized in sessions chaired by worldwide well-known expert scientists. Interesting and scientifically outstanding plenary lectures were given by the invited guests. This special issue of Meteorological Applications contains papers reviewed and selected from the contributions presented in Brdo during the MMC 2014 (Figure 2). In addition to the MMC 2014 conference, interesting satellite events were planned: a free-of-charge certified training course in metrology for meteorological operators, the MeteoMet final meeting and the MeteoMet2 follow-up project kick-off meeting, and the first meeting of the EURAMET Task group on Environment. All of these represent fruitful moments for improving the knowledge transfer and the planning of activities among the participants. The event was supported by MeteoMet: the project funded part of the costs, enabling attendance to the free-of-charge training course. International institutions from both communities endorsed the event: the Technical committee on temperature (TC12) of the international confederation of metrology institutes (IMEKO), the World Meteorological Organization with the Commission of Instruments and Methods of observations (CIMO-WMO), the GRUAN, the International Surface Temperature Initiative, the International Association for the Properties of Water and Steam (APWS), Asia-Pacific Metrology Programme (APMP), EURAMET, with the technical committee on temperature, the technical committee on chemistry and quantity of matter, and the task group on environment. This special issue includes 10 selected articles from the MMC 2014 conference. The opening paper, ‘The MeteoMet project – Metrology for Meteorology: Challenges and results’ (Merlone et al., 2015a) describes the European Joint Research Project, MeteoMet, promoter of the Conference. It summarizes the main results achieved by the project partners, the wide range of collaborations established and the open challenges in the various research aspects of the project tasks. The second paper, ‘A combined non-contact acoustic thermometer and infrared hygrometer for atmospheric measurements’ (Underwood et al., 2015) describes an interesting application of acoustic techniques as solution to overcome the main problem of contact measurements of variables such as temperature, humidity and pressure. The proposed devices are still prototypes, but demonstrated valuable results for direct thermodynamic measurements. The third paper is by Sparasci et al. (2015) with the title ‘Submillimetre thermistors for balloon-borne applications up to lower stratosphere: preliminary characterization with 0.02 k uncertainty’. The group has long experience in primary thermometry and the paper is an interesting effort to fully characterize modern thermistors in terms of measurement uncertainty in extreme conditions. A novel special chamber for the calibration of temperature and pressure sensors of automatic weather stations is described in the fourth paper ‘A calibration facility for automatic weather stations’ (Lopardo et al., 2015). The system allows calibration of temperature and pressure sensors and the evaluation of the mutual influences and the calculation of the covariances in the calibration curves. The fifth paper, ‘In situ calibration of meteorological sensors in the Himalayan mountain environment’ (Merlone et al., 2015b) reports a challenging calibration campaign performed in the Everest Pyramid at 5050 m of altitude in the Nepalese side of Mount Everest, close to Base Camp. A special calibration chamber, made in reduced dimensions and in detachable pieces, each of <30 kg of weight, was manufactured at the Italian Institute of Metrology. The system was delivered and assembled at the Pyramid. The calibration of a representative number of sensors operating in the close area was performed with this system, as it contains reference instruments for pressure and temperature, directly traceable to primary standards. The following paper ‘Arctic metrology: calibration of radiosondes ground check sensors in Ny Ålesund’ (Musachio et al., 2015) reports on a calibration campaign performed in Ny Ålesund, the northern-most village and research area. A calibration chamber was shipped and used to calibrate the sensors needed in the pre-launch ground check of radiosondes for the GRUAN station operating in this extreme environment. The advantages of an in situ calibration are highlighted in the paper. The work of Begeš et al. (2015) on ‘Automatic weather stations and the quality function deployment (QFD) method’ describes an interesting algorithm that checks the quality characteristics of a complete measurement system, including the software aspects, its use and calibration. Based on the results of a questionnaire, the work was applied to a large representative number of devices and users at the European level, aiming to improve the reliability of ground-based measurements. Grykałowska et al. (2015) present ‘The basics of calibration procedure and estimation of uncertainty budget for meteorological temperature sensors’, reporting an accurate procedure for the calibration of weather sensors in the climatic chamber against references of primary level. A complete and detailed analysis of the sources of uncertainty and their evaluation is reported. ‘Validation of the 1290 MHz windprofiler at Payerne, Switzerland, using radiosonde GPS wind measurements’ (Haefele et al., 2015) reports on the metrological validation of the 1290 MHz Doppler radar, used to measure horizontal winds. The uncertainty is evaluated both from theoretical considerations and from a large set of data from radiosonde wind profiles. The final paper of this special issue is ‘Metrological analysis of gravimetric calibration systems for tipping-bucket rain gauges’ (Santana et al., 2015). The authors work at the WMO Regional Instrument Center on Precipitation (University of Genoa, Italy). It summarizes the open issues in hydro-meteorological monitoring when attempting to meet the safety and protection requirements. Following a robust aetiologic approach, the authors propose accurate calibration procedures for a commonly used type of rain gauge. At the time of publication of this special issue of Meteorological Applications, the latest MMC has been planned for and is close to be announced. It will be held in conjunction with the WMO CIMO TECO Conference, in Madrid from 26 to 30 September 2016. The joint event confirms the effectiveness of the collaboration and will bring mutual benefit and wider participation to both the conferences. This event would not have been possible without the help of some enthusiastic staff: Chiara Musacchio and Francesca Sanna from INRiM have been fundamental for the scientific and organizational aspects of the conference program; Domen Hudoklin and Jovan Bojkovski from UL-LMK gave a fundamental contribution through web site and conference management. Acknowledgement is well deserved by members of the Scientific and Organizing Committees for their strong promotion of the event: Jovan Bojkovski (UL FE, Slovenia); Miruna Dobre (SMD, Belgium); Janko Drnovšek (UL FE, EURAMET Vice Chair); Domen Hudoklin (UL FE, Slovenia); Andrea Merlone (INRiM, Italy); Chiara Musacchio (INRiM, Italy); Igor Pušnik (UL FE, Slovenia); Francesca Sanna (IMAMOTER-CNR, Italy); Anne Trumpfheller (EURAMET Communication Officer, Germany); Stephanie Bell (NPL, Great Britain), CCT-WG6 Chair; Rainer Feistel (IAPWS, Germany); Carmen Garcia Izquierdo (CEM, Spain); Drago Groselj (WMO-CIMO, ARSO, Slovenia); Martti Heinonen (MIKES, Finland); Susanne Picard (BIPM, Sèvres); Fernando Sparasci (CNAM, France); Peter Thorne (NOAA, USA), GRUAN Chairperson; Yong-Gyoo Kim (KRISS, Korea), APMP TCT Chair; Davor Zvizdić (IMEKO TC12 Chair, HMI-FSB, Croatia).