Improvement of winter precipitation measurements in Hokuriku region [Japan].
1994
Ohno H. | Wiesinger T. | Takami S.
This study was undertaken to improve winter precipitation measurements in the areas where heavy snowfall occurs in winter. A high-precision, storage precipitation gage was developed, and performance of the existing gages was evaluated, using the Double Fence International Reference gage as specified by WMO. The gage we developed consists of a cylinder-shaped container that incorporates antifreeze solution to melt snow and a quartz-crystal pressure sensor to detect mass of the contained liquid. Field trials over three winters showed that the averages of its output signals provide caught precipitation as accurately as the existing standard precipitation gages. Moreover, the standard deviations of its output signals can indicate the catch efficiency, thereby making the instrument as a self-correcting precipitation gage. The instrument is simple, robust and can be batter-operated over a winter. Catch efficiency at a given wind speed was consistently, albeit slightly, higher for a over-flow type gage than a tipping bucket gage. Overall catch efficiency, averaged over a period of one to two months, was 0.8 for the over-flow type gage and 0.7-0.8 for the tipping bucket gage. Thus, the present measurements are likely to underestimate winter precipitation in Hokuriku region by up to 20%.
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