SYMON'S NON RECORDING RAIN GAUGE

SYMON'S NON  RECORDING RAIN GAUGE

Standard non-recording
ingauge prescribed by the IMD is the Symon's raingauge.

The gauge consists of a funnel with a sharp edged rim of 127mm diameter, a
cylindrical body, a receiver with a narrow neck and handle and a splayed base swhich
is fixed in the ground.
The rain gauge should have a narrow-neck and should be sufficiently protected from radiation to minimize the loss of water from the receiver by evaporation.
To prevent rain from splashing in and out, the vertical wall of the  sharp edgedrim  ismade deep enough and the slope of ftunnel steep enough (at least
45°). The rain falling into the funnel is collected in the receiver kept inside the body and is measured by means of a special measure glass (supplied along with the gauge)
which is graduated in mm. The receiver has a capacity of 175 mm of rain. In regions of
heavy rainfall, raingauges with receivers of 375 mm or 1000 mm capacity may bei
used.
The measure glass has a capacity of 25 mm and can be read to nearest 0.1 mm. The
gauge is fixed on a masonry or concrete foundation of size 60 cm x 60 cn x 60 cm
which is sunk into the ground. Into this foundation the base of the gauge is cemented,
so that the rim of the gauge is exactly 30 cm above the ground level. The top of the
gauge should be perfectly horizontal.