scholarly journals Salinity and relative humidity: climatological relevance and metrological needs

ACTA IMEKO ◽  
2015 ◽  
Vol 4 (4) ◽  
pp. 57 ◽  
Author(s):  
Rainer Feistel
Keyword(s):  
Relative Humidity ◽  
State Of The Art ◽  
Numerical Models ◽  
International System ◽  
Metrological Traceability ◽  
Ocean Surface ◽  
International Standards ◽  
Surface Salinity ◽  
Climatic Trends ◽  
System Of Units

Water plays the leading thermodynamic role in Earth's 'steam engine' climate. Followed by clouds and CO<sub>2</sub>, water vapour in the atmosphere is dominating the greenhouse effect. Evaporation from the ocean surface is the main route of energy export from the ocean, the rate of which is known with poor 20 % uncertainty only. Regional climatic trends in evaporation and precipitation are reflected in small changes of ocean surface salinity.<br /> Observational data of salinity and relative humidity need to be globally comparable within requisite uncertainties over decades and centuries, but both quantities rely on century-old provisional standards of unclear stability, and on ambiguous definitions. This increasingly urgent and long-pending problem can only be solved by proper metrological traceability to the International System of Units (SI). Consistent with such SI-based definitions, state-of-the-art correlation equations for thermophysical properties of water, seawater, ice and humid air such as those available from the recent oceanographic standard TEOS-10 need to be developed and adopted as joint international standards for all branches of climate research, in oceanography, meteorology and glaciology for data analysis and numerical models.<br /> The IAPSO/SCOR/IAPWS Joint Committee on Seawater JCS is targeting at these aims in cooperation with BIPM, WMO and other international bodies.

Performance criteria for reference measurement procedures and reference materials

2015 ◽  
Vol 53 (6) ◽  
Author(s):  
Heinz Schimmel ◽  
Ingrid Zegers
Keyword(s):  
Reference Materials ◽  
International System ◽  
Metrological Traceability ◽  
International Standards ◽  
Performance Criteria ◽  
Systematic Bias ◽  
End User ◽  
Reference Measurement ◽  
System Of Units ◽  
Measurement Results

AbstractThe concept of metrological traceability of measurement results to property values assigned to measurement standards of higher metrological order or to the International System of Units (SI) through sequential calibrations, using reference materials and reference measurement procedures, plays a key role in ensuring that end user measurement procedures perform at an acceptable level in the clinical context. The aim is that measurement results produced over time or by different end users or with different end user measurement procedures for the same measurand will be equivalent within their corresponding uncertainties. These goals can only be reached under certain conditions and if requirements laid down in international standards on calibration concepts, reference measurement procedures and reference materials are fulfilled. Calibration hierarchies have to be implemented correctly and parameters contributing to measurement uncertainty and systematic bias need to be controlled and eliminated, respectively, by technically improving methods and reference materials and intermediate calibrators used for effectively achieving equivalence of measurement results and for meeting analytical performance requirements for in vitro diagnostic devices.

scholarly journals A Blackbody Design for SI-Traceable Radiometry for Earth Observation

2008 ◽  
Vol 25 (11) ◽  
pp. 2046-2054 ◽  
Author(s):  
P. Jonathan Gero ◽  
John A. Dykema ◽  
James G. Anderson
Keyword(s):  
Phase Transitions ◽  
Temperature Scale ◽  
International System ◽  
Thermal Infrared ◽  
Earth Observation ◽  
International Standards ◽  
Future Climate Change ◽  
Single Temperature ◽  
System Of Units ◽  
Infrared Measurements

Abstract Spaceborne measurements pinned to international standards are needed to monitor the earth’s climate, quantify human influence thereon, and test forecasts of future climate change. The International System of Units (SI, from the French for Système International d’Unités) provides ideal measurement standards for radiometry as they can be realized anywhere, at any time in the future. The challenge is to credibly prove on-orbit accuracy at a claimed level against these international standards. The most accurate measurements of thermal infrared spectra are achieved with blackbody-based calibration. Thus, SI-traceability is obtained through the kelvin scale, making thermometry the foundation for on-orbit SI-traceable spectral infrared measurements. Thermodynamic phase transitions are well established as reproducible temperature standards and form the basis of the international practical temperature scale (International Temperature Scale of 1990, ITS-90). Appropriate phase transitions are known in the temperature range relevant to thermal infrared earth observation (190–330 K) that can be packaged such that they are chemically stable over the lifetime of a space mission, providing robust and traceable temperature calibrations. A prototype blackbody is presented that is compact, highly emissive, thermally stable and homogeneous, and incorporates a small gallium melting point cell. Precision thermal control of the blackbody allows the phase transition to be identified to within 5 mK. Based on these results, the viability of end-to-end thermometric calibration of both single-temperature and variable-temperature blackbodies on orbit by employing multiple-phase-change cells was demonstrated.

scholarly journals Thermodynamic Properties of Seawater, Ice and Humid Air: TEOS-10, Before and Beyond

2018 ◽  
Author(s):  
Rainer Feistel
Keyword(s):  
Hydrological Cycle ◽  
International System ◽  
Metrological Traceability ◽  
Humid Air ◽  
Ongoing Research ◽  
Seawater Salinity ◽  
System Of Units ◽  
Atmospheric Relative Humidity ◽  
Definition Of ◽  
First Time

Abstract. In the terrestrial climate system, water is a key player in the form of its different ambient phases of ice, liquid and vapour, admixed with sea salt in the ocean and with dry air in the atmosphere. For proper balances of climatic energy and entropy fluxes in models and observation, a highly accurate, consistent and comprehensive thermodynamic standard framework is requisite in geophysics and climate research. The new “Thermodynamic Equation of Seawater – 2010” (TEOS-10) constitutes such a standard for properties of water in its various manifestations in the hydrological cycle. TEOS-10 has been recommended internationally in 2009 by the Intergovernmental Oceanographic Commission (IOC) to replace the previous 1980 seawater standard, EOS-80, and in 2011 by the International Union of Geodesy and Geophysics (IUGG) “as the official description for the properties of seawater, of ice and of humid air”. This paper briefly reviews the development of TEOS-10, its novel axiomatic properties, new oceanographic tools it offers, and important tasks that still await solutions by ongoing research. Among the latter are new definitions and measurement standards for seawater salinity and pH, in order to establish their metrological traceability to the International System of Units (SI), for the first time after a century of widespread use. Of similar climatological relevance is the development and recommendation of a uniform standard definition of atmospheric relative humidity that is unambiguous and rigorously based on physical principles.

scholarly journals A brief history of metrology: past, present, and future

2019 ◽  
Vol 10 ◽  
pp. 5 ◽  
Author(s):  
Jean-Pierre Fanton
Keyword(s):  
French Revolution ◽  
Quantum Physics ◽  
State Of The Art ◽  
International System ◽  
Actual State ◽  
The Past ◽  
System Of Units ◽  
The World ◽  
History Of ◽  
The Impact

In this paper, we take the freedom to paraphrase Stephen Hawking's well-known formula and approach, for a reflection about metrology. In fact, metrology has a past, a present, and a future. The past is marked by a rich series of events, of which we shall highlight only those which resulted in major turns. The impact of the French Revolution is indisputably one of them. The present corresponds to a significant evolution, which is the entry of metrology into the world of quantum physics, with the relevant changes in the International System of units (SI). An apercu of the actual state of the art of metrological technology is given. The future is characterised by a persisting need for a still enhanced metrology, in terms of performance and domain covered. In this respect, soft metrology seems to constitute a promising field for research and development.

scholarly journals Demonstration of an efficient interpolation technique of inverse time and distance for Oceansat-2 wind measurements at 6-hourly intervals

2017 ◽  
Vol 8 (3) ◽  
pp. 101-112 ◽  
Author(s):  
J Swain ◽  
P A Umesh ◽  
A S N Murty
Keyword(s):  
Wind Speed ◽  
State Of The Art ◽  
Numerical Models ◽  
Ocean Surface ◽  
The State ◽  
Wind Fields ◽  
Interpolation Technique ◽  
Ocean Surface Winds ◽  
Wind Measurements ◽  
Global Oceans

Indian Space Research Organization had launched Oceansat-2 on 23 September 2009, and the scatterometer onboard was a space-borne sensor capable of providing ocean surface winds (both speed and direction) over the globe for a mission life of 5 years. The observations of ocean surface winds from such a space-borne sensor are the potential source of data covering the global oceans and useful for driving the state-of-the-art numerical models for simulating ocean state if assimilated/blended with weather prediction model products. In this study, an efficient interpolation technique of inverse distance and time is demonstrated using the Oceansat-2 wind measurements alone for a selected month of June 2010 to generate gridded outputs. As the data are available only along the satellite tracks and there are obvious data gaps due to various other reasons, Oceansat-2 winds were subjected to spatio-temporal interpolation, and 6-hour global wind fields for the global oceans were generated over 1 × 1 degree grid resolution. Such interpolated wind fields can be used to drive the state-of-the-art numerical models to predict/hindcast ocean-state so as to experiment and test the utility/performance of satellite measurements alone in the absence of blended fields. The technique can be tested for other satellites, which provide wind speed as well as direction data. However, the accuracy of input winds is obviously expected to have a perceptible influence on the predicted ocean-state parameters. Here, some attempts are also made to compare the interpolated Oceansat-2 winds with available buoy measurements and it was found that they are reasonably in good agreement with a correlation coefficient of R > 0.8 and mean deviation 1.04 m/s and 25° for wind speed and direction, respectively.

Metrological Traceability and Roles of Certified Reference Materials

2016 ◽  
Vol 4 (2) ◽  
pp. 81-83
Author(s):  
Akiharu Hioki ◽  
Keyword(s):  
Reference Materials ◽  
Certified Reference Materials ◽  
International System ◽  
Metrological Traceability ◽  
Chemical Analyses ◽  
International Reference ◽  
Calibration And Validation ◽  
Traceability System ◽  
System Of Units ◽  
Metre Convention

Metrological traceability to an international reference, the International System of Units (SI) if possible, is important for the reliability of measurements. The international traceability system under the Metre Convention is briefly introduced. The simplest way to secure metrological traceability in chemical analyses is to utilise certified reference materials (CRMs) for calibration and validation. Finally, as examples of CRMs, NMIJ ones are described.

scholarly journals Thermodynamic properties of seawater, ice and humid air: TEOS-10, before and beyond

Ocean Science ◽  
2018 ◽  
Vol 14 (3) ◽  
pp. 471-502 ◽  
Author(s):  
Rainer Feistel
Keyword(s):  
Thermodynamic Properties ◽  
Hydrological Cycle ◽  
International System ◽  
Metrological Traceability ◽  
Humid Air ◽  
Ongoing Research ◽  
Seawater Salinity ◽  
System Of Units ◽  
Volume Energy ◽  
Definition Of

Abstract. In the terrestrial climate system, water is a key player in the form of its different ambient phases of ice, liquid and vapour, admixed with sea salt in the ocean and with dry air in the atmosphere. For proper balances of climatic energy and entropy fluxes in models and observations, a highly accurate, consistent and comprehensive thermodynamic standard framework is requisite in geophysics and climate research. The new Thermodynamic Equation of Seawater – 2010 (TEOS-10) constitutes such a standard for properties of water in its various manifestations in the hydrological cycle. TEOS-10 was recommended internationally in 2009 by the Intergovernmental Oceanographic Commission (IOC) to replace the previous 1980 seawater standard, EOS-80, and in 2011 by the International Union of Geodesy and Geophysics (IUGG) as the official description for the properties of seawater, of ice and of humid air. This paper briefly reviews the development of TEOS-10, its novel axiomatic properties, the new oceanographic tools it offers and the important tasks that still await solutions by ongoing research. Among the latter are new definitions and measurement standards for seawater salinity and pH in order to establish their metrological traceability to the International System of Units (SI) for the first time after a century of widespread use. Of similar climatological relevance is the development and recommendation of a uniform standard definition of atmospheric relative humidity that is unambiguous and rigorously based on physical principles.The leading thermodynamic properties of a fluid are determined by the relations which exist between volume, pressure, temperature, energy, and entropy … But all the relations existing between these five quantities for any substance …may be deduced from the single relation existing for that substance between volume, energy, and entropy. Josiah Willard Gibbs, 1873b

scholarly journals Establishing SI-Traceability of Nanoparticle Size Values Measured with Line-Start Incremental Centrifugal Liquid Sedimentation

Separations ◽  
2019 ◽  
Vol 6 (1) ◽  
pp. 15
Author(s):  
Vikram Kestens ◽  
Victoria A. Coleman ◽  
Jan Herrmann ◽  
Caterina Minelli ◽  
Alex G. Shard ◽  
...  
Keyword(s):  
Particle Size ◽  
Certified Reference Materials ◽  
International System ◽  
Metrological Traceability ◽  
Metrological Reliability ◽  
Limited Information ◽  
System Of Units ◽  
Si Traceability ◽  
Calibration Materials ◽  
Traceability Networks

Line-start incremental centrifugal liquid sedimentation (disc-CLS) is a powerful technique to determine particle size based on the principles of Stokes’ law. As most input quantities of the Stokes equation cannot be easily determined for typical instruments used for this method, an alternative method which depends on calibrating the sedimentation time scale with reference particles has become common practice. Unfortunately, most of these calibration materials (calibrants) come with limited information regarding their metrological reliability (e.g., lack of measurement uncertainties and traceability statements, incomplete measurand definitions). As a consequence, routine particle size results obtained by disc-CLS are mostly only traceable to the calibrant used, and effective comparisons can only be made for those results originating from measurements performed with the same types of calibrants. In this study, we discuss the concept of metrological traceability and demonstrate that particle size results obtained by disc-CLS can be traceable to the ultimate metrological reference, i.e., the unit of length in the International System of Units (SI), the meter. Using the example of two colloidal silica certified reference materials, we describe how laboratories can realize metrological traceability to the SI by simplifying complex traceability networks.

scholarly journals Development of an HPLC method with relative molar sensitivity based on 1H-qNMR to determine acteoside and pedaliin in dried sesame leaf powders and processed foods

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243175
Author(s):  
Takashi Ohtsuki ◽  
Kiyoaki Matsuoka ◽  
Yushiro Fuji ◽  
Yuzo Nishizaki ◽  
Naoko Masumoto ◽  
...  
Keyword(s):  
High Performance ◽  
International System ◽  
Analytical Data ◽  
Metrological Traceability ◽  
Hplc Method ◽  
Processed Foods ◽  
Reference Standard ◽  
Food Ingredients ◽  
System Of Units ◽  
The Cost

A high-performance liquid chromatography (HPLC) method with relative molar sensitivity (RMS) based on 1H quantitative NMR spectroscopy (1H-qNMR) has been developed for food ingredients such as acteoside (verbascoside) and pedaliin (pedalitin-6-O-glucoside) without requiring authentic and identical standards as the reliable analytical methods. This method is used methyl 4-hydroxybenzoate (MHB) as an alternative reference standard. Each RMS is also calculated from the ratio of each analyte's molar absorption coefficient to that of MHB after correcting the purities of the analytes and reference standard by 1H-qNMR. Therefore, this method can quantify several analytes with metrological traceability to the International System of Units (SI) using the RMS and one alternative reference standard. In this study, the content of acteoside and pedaliin in several samples, such as dried sesame leaf powders and commercially processed foods, can be determined by the proposed RMS method and demonstrated in good agreement that obtained by a conventional method. Moreover, the proposed method yields analytical data with SI-traceability without the need for an authentic and identical analyte standard. Thus, the proposed RMS method is a useful and practical tool for determining acteoside and pedaliin in terms of the accuracy of quantitative values, the routine analysis, and the cost of reagents.

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