A device of ventilation pipe for yearly observation of air temperature in heavy snowfall area, and estimation of snow cover period

Abstract

Yearly observations of temperature and maximum depth of snow-cover were carried in 1989-'91 at six points setlled in beech forests respectively. On the record of temperature observed at five points where the maximum depth of snow-cover reached to over the sensor's height of thermometer as 150cm above ground, many specific tendencies were shown in winter season. It was thought that the reason for appearance of these tendencies is sensor, which is set inside a ventilation pipe, being buried under snow layer. Therefore, next analyses were carried to confirm the reason; cross comparison with three records as seasonal change of temperature (air or snow), estimated air temperature on the snow and depth of snow-cover which is observed nearest weather station; comparison of temperature (air or snow) with depth of snow they were observed simultaneously at a moutainous temporary observation site; experimental observation carried in Tsukuba. By these analyses some facts are established as follows; each specific tendencies are caused by the effect of snow-cover on the ventilation pipe, the beggining day when ventilation pipe had been buried in snow can be estimated from temperature record less than range two days, the appearance day of the ventilation pipe up to snow surface with snow melting can be estimated less range six days in this case.