The project will deliver advances to an international science area of critical importance to future global sustainability. The dissemination and impact will be based on the network of collaborators, established during the previous JRP ENV07 MeteoMet. The vision of this JRP is to establish a permanent collaboration between metrology and meteorology communities, for the benefit of the future generations of climatologists. The impact effort is demonstrated also by the involvement of key international stakeholders such as GRUAN5, ISTI6, IAPWS7, main manufacturers and several others.

Direct impact

The improvement of calibration procedures and measurement techniques for some ECVs, the improvement of measurement devices and their use in field activities, the investigations on sensor characteristics in this project have a common objective: improve the data quality for more reliable climate considerations.

Economical Impact

The high quality data will have numerous applications in economic sectors as agriculture, energy, transport, forestry and tourism. Furthermore, the characterization of meteorological sensors will give an important feedback for the construction of improved instruments and sensors with a large impact on European market competitiveness.

Social Impact

Climate change is also a significant and emerging threat to public health. The inclusion of uncertainties in climate data will strongly reduce controversies on trends and consequently reduce the mitigation actions upon purely political decisions.

Impact on EC Directives and other relevant standards

The project results are expected to contribute to the improvement of:

• Sensor characteristics – ISO 17714:2007 and CCT8 WG2 and WG6 guide on secondary thermometry and humidity – Soil moisture
• ISO/TS 17892-1:2004, and ISO 11271:2002
• Siting uncertainty evaluation – CIMO-XV/Doc. 4 and CIMO Expert team on standardisation documents
• Oceanic sensors – European Earth Observation Programme “Copernicus” 9
• Permafrost temperature measurements techniques – EU funded PermaNET network 10

Air

To investigate the performance of humidity sensors in real working conditions, reference systems will be developed to validate reference instruments and test facilities for radiosonde and airborne sensors. Two types of sensors for fast changing ECVs will be improved: a microwave hygrometer, and a reference free space instrument for temperature and humidity detection. To improve the reliability of humidity measurements a facility to quantify the enhancement factors for measurements under atmospheric conditions will be built.

Sea

A comprehensive study of the pressure dependence of the most widespread deep-sea thermometers will be carried out, as well as an analysis of the temperature-resistance linearization model. A facility for determining temperature and pressure effects on a new generation of absolute salinometers – based on the measurement of seawater refraction index – will be manufactured. Optic-fibers based on Bragg grating will be conceived, studied and metrologically characterized as distributed temperature sensors for sea-surface and sea-profile temperature traceable measurements.

Land

Metrological procedures to evaluate intrinsic characteristics of air thermometers and humidity sensors plus radiation shield will be developed. The effect of influence parameters, such as: sensors siting, rain, and albedo on air temperature measurements, will be analyzed.

Procedures for comparison of laboratories and instruments will be defined in order to give consistency and coherence at the meteorological measurements taken in different places.

Procedures for traceable dynamic calibrations of hygrometers for the air humidity near Earth surface will be developed. New fast step change humidity generators will be manufactured and validated using traceable spectroscopic methods like as TDLAS3 or CRDS4.

A laboratory facility will be constructed to carry out a metrological comparison of the two current methods to measure permafrost temperature (buried or in pipe thermometers along the well drilled in the soil) and to develop calibration procedure, measurements technique, and uncertainty evaluation methods associated with the best technique.

As stated by GCOS “Long-term, high-quality and uninterrupted observations of the atmosphere, land and ocean are vital for all countries, as their economies and societies become increasingly affected by climate variability and change”. High-quality observations are possible only if they are based on a sustained traceability to SI and with uncertainties associated to the measured ECVs.

Air

Air humidity is a key parameter in climate processes. A big challenge, for humidity sensors, is the wide dynamic range with a factor of more than 10000 of water content in the atmosphere. Reliable measurements require sensitive and fast responding sensors to quantify dynamic changes characterizing the phenomenon. Radiosondes sensors calibration protocols need to be improved and validated, to cover real conditions.

Sea

Two of the key oceanic ECVs, for monitoring and understanding decadal changes in heat content and transport, are temperature and salinity. A comprehensive study of the effect of the main quantities of influence (water pressure and temperature) on thermometers and salinometers is needed, for reducing measurement uncertainty, and validating their characterization.

Land

For land ECVs consistent measurement uncertainties calculations need complete knowledge of the measurement system: its intrinsic behaviour, other parameters of influence, siting etc.

WMO/CIMO2 notices the “importance of instrument intercomparison as a tool to improve the data traceability and the uncertainty calculation and to improve operational and maintenance procedures”. Although at present meteorological calibration laboratory intercomparisons are not satisfactory to guarantee full traceability and data comparability, and a well-defined protocol is missing.

Though the permafrost temperature is classified as a parameter to investigate climate changes, at present few or none are the measurement procedures reporting fully detailed uncertainty budget.

Calibration and measurements standards for precipitation and soil moisture are not yet well enough developed to solve differences between laboratory setup and natural conditions.