CEN/TR 17909:2023
(Main)Hydrometry - On-site measurement of snow depth and depth of snowfall
Hydrometry - On-site measurement of snow depth and depth of snowfall
This document defines the requirements for on-site measurements of snow depth and depth of snowfall. This document provides guidance on manual and automatic measuring techniques, and information about sources of errors and measurement uncertainty.
Vor-Ort-Messung der Schneehöhe und der Schneefalltiefe
Mesurage sur site de la profondeur de neige et de la profondeur de la chute de neige
Hidrometrija - Merjenje globine snega in višine snežnih padavin na kraju samem
Ta dokument določa zahteve za meritve višine snežne odeje in višine novozapadlega snega na kraju samem. Določa usmeritve za tehnike ročnega in samodejnega merjenja in informacije o virih napak in merilni negotovosti.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-maj-2023
Hidrometrija - Merjenje globine snega in višine snežnih padavin na kraju samem
Hydrometry - On-site measurement of snow depth and depth of snowfall
Vor-Ort-Messung der Schneehöhe und der Schneefalltiefe
Mesurage sur site de la profondeur de neige et de la profondeur de la chute de neige
Ta slovenski standard je istoveten z: CEN/TR 17909:2023
ICS:
07.060 Geologija. Meteorologija. Geology. Meteorology.
Hidrologija Hydrology
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
CEN/TR 17909
TECHNICAL REPORT
RAPPORT TECHNIQUE
March 2023
TECHNISCHER REPORT
ICS 07.060
English Version
Hydrometry - On-site measurement of snow depth and
depth of snowfall
Mesurage sur site de la profondeur de neige et de la Vor-Ort-Messung der Schneehöhe und der
profondeur de la chute de neige Schneefalltiefe
This Technical Report was approved by CEN on 6 February 2023. It has been drawn up by the Technical Committee CEN/TC 318.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 17909:2023 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Symbols . 10
5 Principles . 10
5.1 General . 10
5.2 Snow depth . 11
5.3 Depth of snowfall. 12
6 Measurement principles . 12
7 Siting and exposure . 12
7.1 General . 12
7.2 Terrain . 13
7.3 Wind . 13
7.4 Thermal radiation . 13
7.5 Obstacles . 13
7.6 Disturbance by humans and animals . 13
7.7 Maintenance of measurement site . 13
8 Measurement of snow depth . 14
8.1 General . 14
8.2 Calibration . 14
8.3 Manual measurements . 15
8.3.1 Measurement techniques . 15
8.3.2 Procedure. 15
8.4 Sources of error . 16
8.4.1 General . 16
8.4.2 Reading errors . 16
8.4.3 Misjudgement of the base level . 17
8.5 Automated measurements . 17
8.5.1 General . 17
8.5.2 Ultrasonic measurements . 18
8.5.3 Optical measurements . 20
8.5.4 Data quality control . 23
8.6 Sources of error . 23
8.6.1 General . 23
8.6.2 Optic measurements . 24
8.6.3 Ultrasonic measurements . 24
8.7 Choice of measuring method . 24
9 Measurement of depth of snowfall . 24
9.1 General . 24
9.2 Measurement . 25
9.2.1 Measurement techniques . 25
9.2.2 Procedure . 25
9.3 Sources of error . 26
10 Quality assurance . 26
Annex A (informative) Snow stake . 27
Annex B (informative) Manual snow depth measuring devices . 28
Annex C (informative) Electronic probe . 29
Annex D (informative) Ultrasonic snow depth measuring station . 30
Annex E (informative) Laser snow depth measuring station . 31
Annex F (informative) Snow board . 32
Bibliography . 33
European foreword
This document (CEN/TR 17909:2023) has been prepared by CEN/TC 318 “Hydrometry”, the secretariat
of which is held by BSI.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
Introduction
Snow depth, representative within a given area, is one of the most difficult weather parameters to be
measured in an accurate and consistent manner. Together with snow density it is the most important
factor in the estimation of snow water equivalent and thus of crucial importance for the assessment of
threatening hazards such as flooding, snow avalanches and building collapses. Preventive measures due
to the knowledge of snow amounts can save lives, properties and infrastructure. The data has a wide
variety of users, including national weather and hydrological services, waterpower industry, snow
avalanche forecasters, climate researchers, water resource managers, construction engineers, winter
resort managers, farmers, and many others.
In addition to weather forecasts, measurements of depth of snowfall (also called new snow height) are
essential in the preparedness of winter road plowing and airport snow removal. Resources can be
adapted to the current weather situation and serious traffic break downs can be reduced.
Much of the information in this document is based on the World Meteorological Organization (WMO)
Guide to Meteorological Instruments and Methods of Observation, Volume II – Measurement of
Cryospheric Variables, published in 2018.
1 Scope
This document defines the requirements for on-site measurements of snow depth and depth of
snowfall. This document provides guidance on manual and automatic measuring techniques, and
information about sources of errors and measurement uncertainty.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
ablation
combined processes (such as sublimation, fusion or melting, evaporation and movement due to wind
and avalanches) that remove snow or ice from the surface of a glacier or from a snow field
[SOURCE: EN ISO 772:2022, 10.1]
3.2
blowing snow
snow being transported by wind high (approximately 2 m) above a snowpack (3.27) surface, where
visibility is noticeably reduced
Note 1 to entry: See also drifting snow (3.3).
[SOURCE: EN ISO 772:2022, 10.2]
3.3
drifting snow
snow being lifted from the snow surface and transported by wind just above the snow surface (3.23),
where visibility is not noticeably reduced
Note 1 to entry: See also blowing snow (3.2).
[SOURCE: EN ISO 772:2022, 10.6]
3.4
new snow
snow layer that is not transformed, densified or settled, from current or recent precipitation having
characteristic grain size range of 1 mm to 3 mm
Note 1 to entry: New snow height can be measured by use of a snow board (3.8).
[SOURCE: EN ISO 772:2022, 10.11]
3.5
old snow
snow layers deposited from earlier precipitation, prior to fresh fallen snow, composed of
metamorphosed snow crystals
[SOURCE: EN ISO 772:2022, 10.12]
3.6
snow accumulation
all processes that add mass to the snowpack (3.27)
EXAMPLE Solid and
...
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