Advances in humidity measurement applications in metrology

Dissertation

Hannu Sairanen

    Research output: ThesisDissertationCollection of Articles

    Abstract

    A significant part of the development of humidity measurement applications in metrology is carried out due to the climate change. Within this thesis metrology tools for humidity measurements in energy gases were developed. In addition, a new method and apparatus for radiosonde calibrations were developed and constructed to provide traceability to the System of Units (SI) and thus improve the quality of radiosonde measured humidity data. Metrology tools for humidity measurements of energy gases were developed by studying the water vapour enhancement factor for methane. A new hygrometer-based calibration method was developed and a set-up was assembled for calibrations of liquid microflows from syringe pumps. Metrological validation for the set-up including uncertainty analysis was carried out for flow rates from 0.1 ul min-1 to 10 ul min-1. The set-up was applied in development and construction of a novel apparatus to measure the enhancement factor. The apparatus was metrologically validated by air and methane measurements for pressures up to 6 MPa and dew/frost-point temperatures from -50 °C to +15 °C. Utilising this apparatus, new experimental enhancement factor data was measured. Along with literature data on equilibrium states of water vapour in methane, new literature-based enhancement factors were calculated. The experimental and the calculated data were combined and an equation expressed as a function of pressure and dew-pointe temperature was fitted to the data. The equation covers dew/frostpoint temperature range from -23 °C to +20 °C and pressures below 7 MPa and its expanded uncertainty (k = 2) is 0.23 in the whole range. Radiosondes operate over a wide range of humidity, temperature and pressure values and thus their calibrations should also cover these conditions. However, calibrations performed with traditional methods at cold temperatures and low humidity require a lot of time and therefore a customized apparatus was developed and constructed. The new apparatus enables significantly shorter calibration times within the temperature range from -80 °C to +20 °C and the dew/frost-point temperature range between -90 °C and +10 °C. The apparatus fulfils the requirements set by Global Climate Observing System (GCOS) and its GCOS Reference Upper-Air Network (GRUAN).
    Original languageEnglish
    QualificationDoctor Degree
    Awarding Institution
    • Aalto University
    Supervisors/Advisors
    • Lahdelma, Risto, Supervisor, External person
    • Heinonen, Martti, Advisor
    Award date21 Dec 2015
    Place of PublicationEspoo
    Publisher
    Print ISBNs978-951-38-8377-5
    Electronic ISBNs978-951-38-8376-8
    Publication statusPublished - 2015
    MoE publication typeG5 Doctoral dissertation (article)

    Fingerprint

    humidity
    dew
    calibration
    radiosonde
    temperature
    methane
    frost
    global climate
    water vapor
    uncertainty analysis
    air
    metrology
    gas
    energy
    pump
    climate change
    liquid
    method

    Keywords

    • calibration
    • dew-point temperature
    • enhancement factor
    • humidity
    • methane
    • radiosonde
    • traceability
    • uncertainty

    Cite this

    Sairanen, H. (2015). Advances in humidity measurement applications in metrology: Dissertation. Espoo: VTT Technical Research Centre of Finland.
    Sairanen, Hannu. / Advances in humidity measurement applications in metrology : Dissertation. Espoo : VTT Technical Research Centre of Finland, 2015. 47 p.
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    abstract = "A significant part of the development of humidity measurement applications in metrology is carried out due to the climate change. Within this thesis metrology tools for humidity measurements in energy gases were developed. In addition, a new method and apparatus for radiosonde calibrations were developed and constructed to provide traceability to the System of Units (SI) and thus improve the quality of radiosonde measured humidity data. Metrology tools for humidity measurements of energy gases were developed by studying the water vapour enhancement factor for methane. A new hygrometer-based calibration method was developed and a set-up was assembled for calibrations of liquid microflows from syringe pumps. Metrological validation for the set-up including uncertainty analysis was carried out for flow rates from 0.1 ul min-1 to 10 ul min-1. The set-up was applied in development and construction of a novel apparatus to measure the enhancement factor. The apparatus was metrologically validated by air and methane measurements for pressures up to 6 MPa and dew/frost-point temperatures from -50 °C to +15 °C. Utilising this apparatus, new experimental enhancement factor data was measured. Along with literature data on equilibrium states of water vapour in methane, new literature-based enhancement factors were calculated. The experimental and the calculated data were combined and an equation expressed as a function of pressure and dew-pointe temperature was fitted to the data. The equation covers dew/frostpoint temperature range from -23 °C to +20 °C and pressures below 7 MPa and its expanded uncertainty (k = 2) is 0.23 in the whole range. Radiosondes operate over a wide range of humidity, temperature and pressure values and thus their calibrations should also cover these conditions. However, calibrations performed with traditional methods at cold temperatures and low humidity require a lot of time and therefore a customized apparatus was developed and constructed. The new apparatus enables significantly shorter calibration times within the temperature range from -80 °C to +20 °C and the dew/frost-point temperature range between -90 °C and +10 °C. The apparatus fulfils the requirements set by Global Climate Observing System (GCOS) and its GCOS Reference Upper-Air Network (GRUAN).",
    keywords = "calibration, dew-point temperature, enhancement factor, humidity, methane, radiosonde, traceability, uncertainty",
    author = "Hannu Sairanen",
    year = "2015",
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    series = "VTT Science",
    publisher = "VTT Technical Research Centre of Finland",
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    Sairanen, H 2015, 'Advances in humidity measurement applications in metrology: Dissertation', Doctor Degree, Aalto University, Espoo.

    Advances in humidity measurement applications in metrology : Dissertation. / Sairanen, Hannu.

    Espoo : VTT Technical Research Centre of Finland, 2015. 47 p.

    Research output: ThesisDissertationCollection of Articles

    TY - THES

    T1 - Advances in humidity measurement applications in metrology

    T2 - Dissertation

    AU - Sairanen, Hannu

    PY - 2015

    Y1 - 2015

    N2 - A significant part of the development of humidity measurement applications in metrology is carried out due to the climate change. Within this thesis metrology tools for humidity measurements in energy gases were developed. In addition, a new method and apparatus for radiosonde calibrations were developed and constructed to provide traceability to the System of Units (SI) and thus improve the quality of radiosonde measured humidity data. Metrology tools for humidity measurements of energy gases were developed by studying the water vapour enhancement factor for methane. A new hygrometer-based calibration method was developed and a set-up was assembled for calibrations of liquid microflows from syringe pumps. Metrological validation for the set-up including uncertainty analysis was carried out for flow rates from 0.1 ul min-1 to 10 ul min-1. The set-up was applied in development and construction of a novel apparatus to measure the enhancement factor. The apparatus was metrologically validated by air and methane measurements for pressures up to 6 MPa and dew/frost-point temperatures from -50 °C to +15 °C. Utilising this apparatus, new experimental enhancement factor data was measured. Along with literature data on equilibrium states of water vapour in methane, new literature-based enhancement factors were calculated. The experimental and the calculated data were combined and an equation expressed as a function of pressure and dew-pointe temperature was fitted to the data. The equation covers dew/frostpoint temperature range from -23 °C to +20 °C and pressures below 7 MPa and its expanded uncertainty (k = 2) is 0.23 in the whole range. Radiosondes operate over a wide range of humidity, temperature and pressure values and thus their calibrations should also cover these conditions. However, calibrations performed with traditional methods at cold temperatures and low humidity require a lot of time and therefore a customized apparatus was developed and constructed. The new apparatus enables significantly shorter calibration times within the temperature range from -80 °C to +20 °C and the dew/frost-point temperature range between -90 °C and +10 °C. The apparatus fulfils the requirements set by Global Climate Observing System (GCOS) and its GCOS Reference Upper-Air Network (GRUAN).

    AB - A significant part of the development of humidity measurement applications in metrology is carried out due to the climate change. Within this thesis metrology tools for humidity measurements in energy gases were developed. In addition, a new method and apparatus for radiosonde calibrations were developed and constructed to provide traceability to the System of Units (SI) and thus improve the quality of radiosonde measured humidity data. Metrology tools for humidity measurements of energy gases were developed by studying the water vapour enhancement factor for methane. A new hygrometer-based calibration method was developed and a set-up was assembled for calibrations of liquid microflows from syringe pumps. Metrological validation for the set-up including uncertainty analysis was carried out for flow rates from 0.1 ul min-1 to 10 ul min-1. The set-up was applied in development and construction of a novel apparatus to measure the enhancement factor. The apparatus was metrologically validated by air and methane measurements for pressures up to 6 MPa and dew/frost-point temperatures from -50 °C to +15 °C. Utilising this apparatus, new experimental enhancement factor data was measured. Along with literature data on equilibrium states of water vapour in methane, new literature-based enhancement factors were calculated. The experimental and the calculated data were combined and an equation expressed as a function of pressure and dew-pointe temperature was fitted to the data. The equation covers dew/frostpoint temperature range from -23 °C to +20 °C and pressures below 7 MPa and its expanded uncertainty (k = 2) is 0.23 in the whole range. Radiosondes operate over a wide range of humidity, temperature and pressure values and thus their calibrations should also cover these conditions. However, calibrations performed with traditional methods at cold temperatures and low humidity require a lot of time and therefore a customized apparatus was developed and constructed. The new apparatus enables significantly shorter calibration times within the temperature range from -80 °C to +20 °C and the dew/frost-point temperature range between -90 °C and +10 °C. The apparatus fulfils the requirements set by Global Climate Observing System (GCOS) and its GCOS Reference Upper-Air Network (GRUAN).

    KW - calibration

    KW - dew-point temperature

    KW - enhancement factor

    KW - humidity

    KW - methane

    KW - radiosonde

    KW - traceability

    KW - uncertainty

    M3 - Dissertation

    SN - 978-951-38-8377-5

    T3 - VTT Science

    PB - VTT Technical Research Centre of Finland

    CY - Espoo

    ER -

    Sairanen H. Advances in humidity measurement applications in metrology: Dissertation. Espoo: VTT Technical Research Centre of Finland, 2015. 47 p.