Rain gauges are instruments used to measure liquid precipitation over time. The first rain gauges date back to ancient Greece around 500 BC. Modern rain gauges generally use a funnel to collect precipitation in a cylinder or tipping bucket. Common types include standard cylinders, weighing buckets, tipping buckets, optical sensors, and acoustic sensors. Rain gauges provide important data for meteorologists and hydrologists.

1. Rain gauge
Done by:-
Chintan
Dharmin
Manav

2. Intro. on rain gauge
• A rain gauge is a type of instrument used
by meteorologists and hydrologists to gather
and measure the amount of
liquid precipitation over a set period of time.

3. History of rain gauge
• The first known rainfall records were kept by
the Ancient Greeks, about 500 B.C. This was
followed 100 years later by people in India using
bowls to record the rainfall.
• While some sources state that the much
later cheugugi of Korea was the world's first
gauge, other sources say that Jang Yeong-
sil developed or refined an existing gauge. In
1662, Christopher Wren created the first tipping-
bucket rain gauge in Britain.

4. Principles of it
• Most rain gauges generally measure the precipitation
in millimeters. The level of rainfall is sometimes reported
as inches or centimeters.
• Rain gauge amounts are read either manually or by automatic
weather station (AWS). The frequency of readings will depend
on the requirements of the collection agency.
• In most cases the precipitation is not retained, however some
stations do submit rainfall (and snowfall) for testing, which is
done to obtain levels of pollutants.
• Another problem encountered is when the temperature is
close to or below freezing. Rain may fall on the funnel and ice
or snow may collect in the gauge and not permit any
subsequent rain to pass through.

5. Types of rain-gauges
• Standard rain gauge
• Weighing precipitation gauge
• Tipping bucket rain gauge
• Optical rain gauge
• Acoustic rain gauge

6. Standard rain gauge
• The standard NOAA rain
gauge, developed
around the start of the
20th century, consists of
a funnel attached to a
graduated cylinder
(2 cm in diameter) that
fits inside a larger
outside container
(20 cm in diameter and
50 cm tall).

7. Weighing precipitation rain gauge
• A weighing-type
precipitation gauge
consists of a storage
bin, which is weighed to
record the mass.

8. Tipping-bucket rain gauge
• The tipping bucket rain
gauge consists of a funnel
that collects and channels
the precipitation into a
small seesaw-like
container. After a pre-set
amount of precipitation
falls, the lever
tips, dumping the
collected water and
sending an electrical
signal.

9. Optical rain gauge
• These have a row of
collection funnels. In an
enclosed space below
each is a laser diode and
a photo transistor
detector. When enough
water is collected to make
a single drop, it drips
from the bottom, falling
into the laser beam path.

10. Acoustic rain gauge
• The acoustic
disdrometer developed
by Stijn de Jong is an
acoustic rain gauge. The
big advantage of this
design is that it is a lot
less costly.