Renseignements généraux

Nº de série

S/O

Nº de partie

1

Nombre total de parties

3

Ou

S/O

Brevets

S/O

Description générale

aluminum

Dimensions

Remarque : Cette information reflète la taille générale pour l’entreposage et ne représente pas nécessairement les véritables dimensions de l’objet.

Longueur

S/O

Largeur

S/O

Hauteur

58,0 cm

Épaisseur

S/O

Poids

S/O

Diamètre

61,0 cm

Volume

S/O

Lexique

Groupe

Météorologie

Catégorie

Mesure de montant, taux et durée de précipitation

Sous-catégorie

S/O

Fabricant

Ou

Environment CA

Pays

Canada

État/province

Inconnu

Ville

Inconnu

Contexte

Pays

Canada

État/province

Ontario

Période

1950's to present; this instrument was apparently in use for 35 years (Ref. 5)

Canada

A meteorological instrument designed by and made by or for the Meteorological Service of Canada.. In Canada, both snow depth and snow/water equivalent are measured and the standard instrument for measuring the latter is the Nipher shielded snow gauge. Since 1953 the MSC has used the Canadian designed Nipher manual gauge at selected stations (Refs.1,2,4). Part of a large collection of meteorological instruments acquired from the Meteorological Service of Canada (previously Atmospheric Environment Service) by the CSTM since 1967. MSC is the government agency responsible for collecting and disseminating meteorological data and forecasts in Canada. It was founded in 1871 in Toronto where it is still headquartered. The MSC was originally on the University of Toronto downtown campus but moved to Downsview in 1971 on land owned by UofT. The headquarters houses laboratories, research facilities and calibration and instrument maintenance facilities (now largely contracted out).

Fonction

An instrument used to to measure the amount of fallen snow by measuring the water content of snow.

Technique

An MSC Nipher snow gauge in three parts: aluminum shield, adjustable stand and a 5" inch diameter brass receiver. The shield shape of the Nipher shield is designed to minimize the turbulent effect of wind over the gauge mouth. This gauge has a receiver with a 12.7 cm (5") orifice and has an exponential cone as a shield. It is adjusted so that the orifice is 1.52 metres (5') off the snow surface. The Nipher, a Canadian design, has an exponential cone which deflects the wind down and away from the orifice of the gauge. Without the shield the snowfall catch by the 5" receiver would be reduced by 70% with winds of 20 m/s. While the Nipher design dates back to 1878, the Canadian exponential cone dates from NRC wind tunnel studies in 1946. The shield is constructed of fibreglass or aluminum in the case of older snow gauges (all shields made after 1979 are fibreglass). Due to the large size of the receiver the wetting losses can become quite substantial in areas with light snowfall like the Canadian arctic. It is the most exact manual snow gauge in the world for determining the water equivalent of snowfall and reads 7% below the DFIR. The standard for snowfall is the Double Fence International Reference (DFIR) which has two 3.5 metre high circular snow fences located two and six metres from the centrally located snow gauge, a Russian Tretrakov gauge, which is also shielded. The orifice of the Tretrakov is mounted level with the top of the fences. There is a 1.5 metre gap at the bottom of the fences to allow surface snow to blow by and not accumulate unnaturally within the fences (Refs. 1,2,4).

Notes sur la région

Inconnu

Détails

Marques

none

Manque

S/O

Fini

unfinished grey aluminum

Décoration

S/O