On the Precipitation Amount at the Period of a Snow-storm

Abstract

In a snow-lay region, it is impossible in particular, at the period of a snow-storm to measure the precipitation amount exactly. This is due to the influence of the shape of orifice type snow gages itself, that is, the upward component of air stream above the orifice.
Then, in order to measure the vertical component of the wind velocity, the 3-bladed vertical anemomter (Thornthwaite type) is used. This anemometer is calibrated with the wind tunnel and field observation are made in a snow-lay region near the Sekiyama Park Hotel, Niigata Prefecture.
The catching rate C of the snow gage (dia. 20 cm) is determined by the empirical formura
C= (1-a·V/F) ×100
where,
V is the wind velocity in m/sec,
a is a constant=0.1 to be determined from the wind tunnel test,
F is the falling velocity of the snow-flakes in m/sec.