scholarly journals The high-resolution extraterrestrial solar spectrum (QASUMEFTS) determined from ground-based solar irradiance measurements

2017 ◽  
Vol 10 (9) ◽  
pp. 3375-3383 ◽  
Author(s):  
Julian Gröbner ◽  
Ingo Kröger ◽  
Luca Egli ◽  
Gregor Hülsen ◽  
Stefan Riechelmann ◽  
...  
Keyword(s):  
High Resolution ◽  
Wavelength Range ◽  
International System ◽  
Metrological Traceability ◽  
Solar Spectrum ◽  
Spectral Irradiance ◽  
Research Centre ◽  
Medium Resolution ◽  
System Of Units ◽  
Extraterrestrial Solar Spectrum

Abstract. A high-resolution extraterrestrial solar spectrum has been determined from ground-based measurements of direct solar spectral irradiance (SSI) over the wavelength range from 300 to 500 nm using the Langley-plot technique. The measurements were obtained at the Izaña Atmospheric Research Centre from the Agencia Estatal de Meteorología, Tenerife, Spain, during the period 12 to 24 September 2016. This solar spectrum (QASUMEFTS) was combined from medium-resolution (bandpass of 0.86 nm) measurements of the QASUME (Quality Assurance of Spectral Ultraviolet Measurements in Europe) spectroradiometer in the wavelength range from 300 to 500 nm and high-resolution measurements (0.025 nm) from a Fourier transform spectroradiometer (FTS) over the wavelength range from 305 to 380 nm. The Kitt Peak solar flux atlas was used to extend this high-resolution solar spectrum to 500 nm. The expanded uncertainties of this solar spectrum are 2 % between 310 and 500 nm and 4 % at 300 nm. The comparison of this solar spectrum with solar spectra measured in space (top of the atmosphere) gave very good agreements in some cases, while in some other cases discrepancies of up to 5 % were observed. The QASUMEFTS solar spectrum represents a benchmark dataset with uncertainties lower than anything previously published. The metrological traceability of the measurements to the International System of Units (SI) is assured by an unbroken chain of calibrations leading to the primary spectral irradiance standard of the Physikalisch-Technische Bundesanstalt in Germany.

scholarly journals A high resolution extra-terrestrial solar spectrum determined from ground-based solar irradiance measurements

2017 ◽  
Author(s):  
Julian Gröbner ◽  
Ingo Kröger ◽  
Luca Egli ◽  
Gregor Hülsen ◽  
Stefan Riechelmann ◽  
...  
Keyword(s):  
High Resolution ◽  
International System ◽  
Metrological Traceability ◽  
Solar Spectrum ◽  
Spectral Irradiance ◽  
Atmospheric Research ◽  
Solar Spectral Irradiance ◽  
Medium Resolution ◽  
System Of Units ◽  
Unbroken Chain

Abstract. A high resolution extraterrestrial solar spectrum has been determined from ground-based measurements of direct solar spectral irradiance over the range 300 nm to 500 nm using the Langley-plot technique. The measurements were obtained at the Iza\\`na Atmospheric Research Center from AEMET, Tenerife, Spain during the period 12 to 24 September 2016. This solar spectrum (QASUMEFTS) was combined from medium resolution (bandpass of 0.86 nm) measurements of the QASUME spectroradiometer in the range 300 nm to 500 nm and high resolution measurements (0.025 nm) from a fourier transform spectroradiometer over the range 305 nm to 380 nm. The KittPeak solar atlas was used to extend this high resolution solar spectrum to 500 nm. The expanded uncertainties of this solar spectrum are 2 % between 310 nm and 500 nm and 4 % at 300 nm. The comparison of this solar spectrum with solar spectra measured in space (top of the atmosphere) gives very good agreements in some cases, while in some other cases discrepancies of up to 5 % could be observed. The QASUMEFTS solar spectrum represents a benchmark dataset with uncertainties lower than anything previously published. The metrological traceability of the measurements to the International System of Units (SI) is assured by an unbroken chain of calibrations leading to the primary spectral irradiance standard of the Physikalisch-Technische Bundesanstalt in Germany.

scholarly journals SOLAR-ISS: A new reference spectrum based on SOLAR/SOLSPEC observations

2018 ◽  
Vol 611 ◽  
pp. A1 ◽  
Author(s):  
M. Meftah ◽  
L. Damé ◽  
D. Bolsée ◽  
A. Hauchecorne ◽  
N. Pereira ◽  
...  
Keyword(s):  
High Resolution ◽  
Wavelength Range ◽  
Solar Physics ◽  
Space Station ◽  
Solar Spectrum ◽  
Total Solar Irradiance ◽  
Spectral Irradiance ◽  
Reference Spectrum ◽  
The Difference ◽  
The Impact

Context. Since April 5, 2008 and up to February 15, 2017, the SOLar SPECtrometer (SOLSPEC) instrument of the SOLAR payload on board the International Space Station (ISS) has performed accurate measurements of solar spectral irradiance (SSI) from the middle ultraviolet to the infrared (165 to 3088 nm). These measurements are of primary importance for a better understanding of solar physics and the impact of solar variability on climate. In particular, a new reference solar spectrum (SOLAR-ISS) is established in April 2008 during the solar minima of cycles 23–24 thanks to revised engineering corrections, improved calibrations, and advanced procedures to account for thermal and aging corrections of the SOLAR/SOLSPEC instrument. Aims. The main objective of this article is to present a new high-resolution solar spectrum with a mean absolute uncertainty of 1.26% at 1σ from 165 to 3000 nm. This solar spectrum is based on solar observations of the SOLAR/SOLSPEC space-based instrument.Methods. The SOLAR/SOLSPEC instrument consists of three separate double monochromators that use concave holographic gratings to cover the middle ultraviolet (UV), visible (VIS), and infrared (IR) domains. Our best ultraviolet, visible, and infrared spectra are merged into a single absolute solar spectrum covering the 165–3000 nm domain. The resulting solar spectrum has a spectral resolution varying between 0.6 and 9.5 nm in the 165–3000 nm wavelength range. We build a new solar reference spectrum (SOLAR-ISS) by constraining existing high-resolution spectra to SOLAR/SOLSPEC observed spectrum. For that purpose, we account for the difference of resolution between the two spectra using the SOLAR/SOLSPEC instrumental slit functions.Results. Using SOLAR/SOLSPEC data, a new solar spectrum covering the 165–3000 nm wavelength range is built and is representative of the 2008 solar minimum. It has a resolution better than 0.1 nm below 1000 nm and 1 nm in the 1000–3000 nm wavelength range. The new solar spectrum (SOLAR-ISS) highlights significant differences with previous solar reference spectra and with solar spectra based on models. The integral of the SOLAR-ISS solar spectrum yields a total solar irradiance of 1372.3 ± 16.9 Wm−2 at 1σ, that is yet 11 Wm−2 over the value recommended by the International Astronomical Union in 2015.

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.

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.

scholarly journals Metrological traceability of oceanographic salinity measurement results

Ocean Science ◽  
2011 ◽  
Vol 7 (1) ◽  
pp. 45-62 ◽  
Author(s):  
S. Seitz ◽  
R. Feistel ◽  
D. G. Wright ◽  
S. Weinreben ◽  
P. Spitzer ◽  
...  
Keyword(s):  
Time Scales ◽  
International System ◽  
Metrological Traceability ◽  
Point Of View ◽  
Measured Quantity ◽  
Additional Contribution ◽  
Small Uncertainty ◽  
System Of Units ◽  
Measurement Results ◽  
Property Changes

Abstract. Consistency of observed oceanographic salinity data is discussed with respect to contemporary metrological concepts. The claimed small uncertainty of salinity measurement results traceable to the conductivity ratio of a certified IAPSO Standard Seawater reference is not metrologically justified if results are compared on climatic time scales. This applies in particular to Practical Salinity SP, Reference Salinity SR, and the latest estimates of Absolute Salinity using the TEOS-10 formalism. On climate time scales an additional contribution to the uncertainty that is related to unknown property changes of the reference material must be accounted for. Moreover, when any of these measured or calculated quantity values is used to estimate Absolute Salinity of a seawater sample under investigation, another uncertainty contribution is required to quantify the accuracy of the equations relating the actually measured quantity to the Absolute Salinity. Without accounting for these additional uncertainties, such results cannot be used to estimate Absolute Salinity with respect to the International System of Units (SI), i.e. to the unit chosen for the mass fraction of dissolved material in the sample, which is "g kg−1". From a metrological point of view, such deficiencies in the calculations involving other quantities will produce SI-incompatible results. We outline how these problems can be overcome by linking salinity to primary SI measurement standards.

scholarly journals Metrological traceability of oceanographic salinity measurement results

2010 ◽  
Vol 7 (4) ◽  
pp. 1303-1346 ◽  
Author(s):  
S. Seitz ◽  
R. Feistel ◽  
D. G. Wright ◽  
S. Weinreben ◽  
P. Spitzer ◽  
...  
Keyword(s):  
Time Scales ◽  
International System ◽  
Metrological Traceability ◽  
Point Of View ◽  
Measured Quantity ◽  
Additional Contribution ◽  
Small Uncertainty ◽  
System Of Units ◽  
Measurement Results ◽  
Property Changes

Abstract. Consistency of observed oceanographic salinity data is discussed with respect to contemporary metrological concepts. The claimed small uncertainty of salinity measurement results traceable to the conductivity ratio of a certified IAPSO Standard Seawater reference is not metrologically justified if results are compared on climatic time scales. This applies in particular to Practical Salinity SP, Reference Salinity SR, and the latest estimates of Absolute Salinity using the TEOS-10 formalism. In climate time scales an additional contribution to the uncertainty that is related to unknown property changes of the reference material must be accounted for. Moreover, when any of these measured or calculated quantity values is used to estimate Absolute Salinity of a seawater sample under investigation, another uncertainty contribution is required to quantify the accuracy of the equations relating the actually measured quantity to the Absolute Salinity. Without accounting for these additional uncertainties, such results cannot be used to estimate Absolute Salinity with respect to the International System of Units (SI), i.e. to the unit chosen for the mass fraction of dissolved material in the sample, which is "g/kg". From a metrological point of view, such deficiencies in the calculations involving other quantities will produce SI-incompatible results. We outline how these problems can be overcome by linking salinity to primary SI measurement standards.

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