ISO/FDIS 8932-1

Meteorology — Radiosonde — Part 1: Laboratory test method for calibration error of temperature sensor in radiosonde

This International Standard proposal specifies technical requirements and test method for temperature sensor in radiosonde. This International Standard is applicable to the temperature measurement traceable to SI unit in boom sensors according to variations of pressure and air speed under the simulated conditions of upper air. This proposed standard will mainly provide a) Terms and definitions b) Technical specification for test instrumentations. c) Test procedure of temperature measurement sensors according to pressure and air speed. d) Uncertainty evaluation of the test procedures. The compensation of solar radiation effects to the temperature sensor will be described in a separate Standard.

Météorologie — Radiosonde — Partie 1: Méthode d'essai en laboratoire pour l'erreur d'étalonnage du capteur de température dans la radiosonde

General Information

• Status: Not Published
• ICS: 07.060 - Geology. Meteorology. Hydrology
• Technical Committee: ISO/TC 146/SC 5 - Meteorology
• Drafting Committee: ISO/TC 146/SC 5 - Meteorology
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 05-Aug-2025
• Completion Date: 05-Aug-2025

Standards Content (Sample)

FINAL DRAFT
International
Standard
ISO/TC 146/SC 5
Meteorology — Radiosonde —
Secretariat: DIN
Part 1:
Voting begins on:
2025-08-05
Laboratory test method for
calibration error of temperature
Voting terminates on:
2025-09-30
sensor in radiosonde
Météorologie — Radiosonde —
Partie 1: Méthode d'essai en laboratoire pour l'erreur
d'étalonnage du capteur de température dans la radiosonde
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 146/SC 5
Meteorology — Radiosonde —
Secretariat: DIN
Part 1:
Voting begins on:
Laboratory test method for
calibration error of temperature
Voting terminates on:
sensor in radiosonde
Météorologie — Radiosonde —
Partie 1: Méthode d'essai en laboratoire pour l'erreur
d'étalonnage du capteur de température dans la radiosonde
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols . 3
4.1 Symbols .3
4.2 Subscript .4
5 Technical requirements for the laboratory setup . 4
5.1 Test chamber .4
5.2 Reference thermometers .4
6 Test procedure for radiosonde temperature sensors . 5
6.1 Preparations .5
6.1.1 Environmental conditions .5
6.1.2 Preparation of radiosonde .5
6.1.3 Installation of radiosonde .5
6.1.4 Examination of laboratory setups .6
7 Test methods and procedures . 7
7.1 Test conditions .7
7.2 Testing sequence .7
7.3 Data collection .7
7.4 Finalization of the test .8
8 Data processing . 8
8.1 Calculation of the reference temperature .8
8.2 Calculation of the measurement error .9
9 Evaluation of measurement uncertainty . 9
9.1 General .9
9.2 Mathematical model of measurement .9
9.3 Equation for combined standard uncertainty .9
9.4 Calculation of expanded uncertainty .10
10 Test report .11
10.1 Method for reporting test results .11
Bibliography .12

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 5,
Meteorology.
A list of all parts in the ISO 8932 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
Temperature and water vapour (i.e. humidity) are two of the basic atmospheric state variables and
important initialization for weather and climate prediction models. In order to measure the temperature
and humidity in the upper-air atmosphere, radiosondes are widely used. Radiosonde is an instrument
intended to be carried by a balloon through the atmosphere, equipped with devices to measure one or
several meteorological variables (such as pressure, temperature and humidity), and provided with a radio-
[1]
transmitter for sending this information to the observing station . Radiosonde observations are often
used in conjunction with other measurement techniques such as remote sensing using satellites in order to
provide comparative data. For radiosonde-derived data to be useful, the measurement accuracy of the radio-
soundings needs to be known.
Thermistors, thin-film platinum resistance thermometers (PRTs), and thermocouples are mostly used as
temperature sensors for radiosonde. Temperature from radiosonde is mainly affected by temperature
sensor calibration and long and short-wave radiation correction. The impact of radiation correction on the
[2],[3] [4]
temperature is treated in a separate document . The temperature-dependent physical quantities, such
as resistance or thermoelectric voltage, have peculiar formulae as a function of temperature. Thermistor
[5]
uses the Steinhart-Hart equation, and Callendar van Dusen (CVD) formula is applied for the PRTs .
Therefore, the temperature accuracy in ground condition mainly depends on the sensor calibration, and
thus an essential prerequisite to improve the measurement reliability of radiosondes is to calibrate the
radiosonde sensors using ground-based facilities.
The temperature generated by a laboratory setup can be traceable to the SI via International Temperature
[6]
Scale of 1990 . The SI traceability of the setup should then be transferred to radiosonde temperature
sensors through calibration by manufacturers. This document is mainly focused on testing the calibration
error of temperature sensors in radiosondes sampled from a batch of mass production.
The Standing Committee on Measurements, Instrumentation and Traceability (SC-MINT) at the World
Meteorological Organization (WMO) urges users to test selected samples of radiosondes under laboratory
conditions in order to ensure that the calibrations supplied by the manufacturer are valid. Unless
radiosonde sensors can be produced in large batches to give the reproducibility and accuracy required
by users, it is necessary to calibrate the instruments and sensors individually. Even if the se
...

ISO/TC 146/SC 5
Secretariat: DIN
Date: 2025-07-21
Meteorology — Radiosonde — —
Part 1:
Laboratory test method for calibration error of temperature
sensor in radiosonde
First edition
Date: 2025-04-16
MUST BE USED
FOR FINAL
Météorologie — Radiosonde —
Partie 1: Méthode d'essai en laboratoire pour l'erreur d'étalonnage du capteur de température dans la
radiosonde
FDIS stage
2 © ISO 2024 – All rights reserved

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: [e-mail]
Website: www.iso.org
Published in Switzerland
iii
Contents
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols . 4
4.1 Symbols . 4
4.2 Subscript . 4
5 Technical requirements for the laboratory setup . 5
5.1 Test chamber . 5
5.2 Reference thermometers . 5
6 Test procedure for radiosonde temperature sensors . 5
6.1 Preparations . 5
7 Test methods and procedures . 8
7.1 Test conditions . 8
7.2 Testing sequence . 8
7.3 Data collection . 10
7.4 Finalization of the test . 11
8 Data processing . 11
8.1 Calculation of the reference temperature . 11
8.2 Calculation of the measurement error . 11
9 Evaluation of measurement uncertainty . 12
9.1 General . 12
9.2 Mathematical model of measurement. 12
9.3 Equation for combined standard uncertainty . 12
9.4 Calculation of expanded uncertainty . 14
10 Test report . 14
10.1 Method for reporting test results . 14
Bibliography . 16

iv
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 5,
Meteorology.
A list of all parts in the ISO 8932 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
Introduction
Temperature and water vapour (i.e.,. humidity) are two of the basic atmospheric state variables and important
initialization for weather and climate prediction models. In order to measure the temperature and humidity
in the upper-air atmosphere, radiosondes are widely used. Radiosonde is an instrument intended to be carried
by a balloon through the atmosphere, equipped with devices to measure one or several meteorological
variables (such as pressure, temperature, and humidity), and provided with a radio-transmitter for sending
[ [1]]
this information to the observing station 0. . Radiosonde observations are often used in conjunction with
other measurement techniques such as remote sensing using satellites in order to provide comparative data.
For radiosonde-derived data to be useful, the measurement accuracy of the radio-soundings needs to be
known.
Thermistors, thin-film platinum resistance thermometers (PRTs), and thermocouples are mostly used as
temperature sensors for radiosonde. Temperature from radiosonde is mainly affected by temperature sensor
calibration and long and short-wave radiation correction. The impact of radiation correction on the
[ ],[ [2,3]] [ [4]]
temperature 0 0 is treated in a separate document 0. . The temperature-dependent physical quantities,
such as resistance or thermoelectric voltage, have peculiar equationsformulae as a function of temperature.
Thermistor uses the Steinhart-Hart equation, and Callendar van Dusen (CVD) formula is applied for the
[ [5]]
PRTs 0. . Therefore, the temperature accuracy in ground condition mainly depends on the sensor calibration,
and thus an essential prerequisite to improve the measurement reliability of radiosondes is to calibrate the
radiosonde sensors using ground-based facilities.
The temperature generated by a laboratory setup can be traceable to the SI via International Temperature
[ [6]]
Scale of 1990 0. . The SI traceability of the setup should then be transferred to radiosonde temperature
sensors through calibration by manufacturers. This document is mainly focused on testing the calibration
error of temperature sensors in radiosondes sampled from a batch of mass production.
The Standing Committee on Measurements, Instrumentation and Traceability (SC-MINT) at the World
Meteorological Organization (WMO) urges users to test selected samples of radiosondes under laboratory
conditions in order to ensure that the calibrations supplied by the manufacturer are valid. Unless radiosonde
sensors can be produced in large batches to give the reproducibility and accuracy required by users, it is
necessary to calibrate the instruments and sensors individually. Even if the sensors can be produced in large
batches to meet an agreed set of standardized performance checks, it is necessary for representative samples,
[ [1]]
selected at random, to be checked in more detail 0. . This independent testing would further improve the
reliability of radiosonde measurements by verifying the calibration results applied by the manufacturers.
Despite the importance of the testing, the test setup in the guide by SC-MINT are limited to stability
(±0,25 °C/min) and systematic errors less than ±0,1 °C, and more detailed methodologies or test procedures
for the testing of radiosonde temperature sensors have not yet been reported.
The procedure presented in this document provides the technical requirements for the laboratory setup, the
test procedure for calibration error of temperature sensors in a radiosonde at relevant temperatures using
the setup, and an evaluation method for the uncertainty of the test results.
vi
Meteorology — Radiosonde — —
Part 1:
Laboratory test method offor calibration error of temperature sensor
in radiosonde
1 Scope
TheThis document specifies a test method in terms of calibration error for radiosonde temperature sensors
sampled from a batch of mass production, with varying temperature in laboratory setups at ground level
pressure. This document elaborates on:
a) a) the technical requirements for test chamber and reference thermometers as essential
laboratory setups to evaluate the calibration errors of radiosonde temperature measurement;
b) b) a test procedure including the installation of radiosondes in the test chamber, the operation of
laboratory setups and the comparison between radiosonde and the temperature references for evaluating
1)
calibration errors of radiosonde temperature sensors for a temperature range of −85 °C to 50 °C at
laboratory conditions; at
c) c) a method for evaluating the uncertainties related to the references and the radiosonde sensors
for the measured radiosonde temperature calibration error.
It should be noted that the calibrationNOTE Calibration error of radiosonde treated here isin this document forms
only a part of the error in radiosonde sounding measurements. Regarding the errors involved in radiosonde temperature
measurement on sounding, it is necessary to consider various errors as shown in Table 2 of Reference [0[7], and]; this
standarddocument provides only a partial evaluation in laboratory tests.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO/IEC Guide 98--1:2009, Uncertainty of measurement — Part 1: Introduction, Guide to the expression of
uncertainty in measurement. — Part 1: Introduction
ISO/IEC Guide 98--3:2008, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
ISO/IEC Guide 99:2007, International vocabulary of metrology — Basic and general concepts and associated
terms (VIM)
WMO No.182, 1992, International Meteorological Vocabulary
IEC 60050--713:2021, International Electrotechnical Vocabulary (IEV) - Part 713: Radiocommunications:
transmitters, receivers, networks and operation

1)
Currently, the lowest possible te
...