Abstract
The catching characteristics of conventional snow gages are quite unsatisfactory.
Yoshida and Saito observed the catching rate C of various snow gages and found that C was given by the following empirical formula,
C=1/(1+mv)
where v is the wind velocity in m/s near the gages orifice and m is the constant for certain snow gage. For J.M. A. standard 20-cm standpipe snowgage m was 0.449.
In order to secure high catching rate, it is neccesary to undisturb the air current above the orifice.
The authers designed a snowgage which had the funnel-shaped head connected to an U-tube. The funnel and it's side of the U-tube is filled with kerosene and the other side is filled with water. The whole system is heated to a certain temperature above 0°C. When the snowflakes enter in the oil, they melt and fall down as waterdrops into this U-tube, and the same mass of water of these drops must overflow from the opening of the water side of the U-tube. The overflown water is measured by the jar for raingage.
From the analysis of the results of field tests, the catching rate of this snowgage is presumed to be shown by the following formula.
C=1/(1+0.24v)
