Rain gauges - size/diameter
Name: ronald miller
Hello, our question is about rain guages. What is the
standard size for a rain gauge.... there must be a specific
volume/diameter for rain gaiuges....??
I've seen rain guages in many sizes, ranging from cylindrical
to trapezoidal shape (small at bottom, bigger at top). I suppose
they could be any size or shape, but what is most important is
the gradient. One cubic inch of water would be different on
different size/shapes of guages. It's a matter of using the
correct formula to calculate water volume based on shape.
Although it seems that there would be a "standard" rain gauge, in fact
you can use many types of containers. The most important thing in
constructing your own gauge is to have a very accurate method for
determining the volume of rain collected. For example, you can use
ordinary soda bottles with a funnel as your gauge. Each day, at the same
time, collect the rain and measure its volume with a graduated cylinder.
Now, to determine how much rain fell use the following:
depth of rainfall = volume of rain water / area of funnel opening
This equation will give the depth of the rainfall. Rain is reported
simply as the depth of the water captured in a vertical-sided container.
So, any straight-sided container, such as a tin can, will work and then,
you won't have to use the equation, just use a ruler to measure the depth
of the water. There are other considerations for accurate precipitatio
measurement. First, you must try to limit evaporation from
your container. Try this, cover your soda bottle with an inverted flower
pot, then insert the funnel through the drain hole and into the bottle.
Also, set rain gauges in locations where they will not be disturbed
by wind turbulence from buildings or trees. Good luck and let me know
how it goes.
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Update: June 2012