Measurement of Rainfall The precipitation is collected and measured in a raingauge. Raingauge can be broadly classified in two categories as The precipitation is collected and measured in a raingauge. Raingauge can be broadly classified in two categories as Nonrecording raingauge Nonrecording raingauge Symon’s type raingauge Recording raingauge Recording raingauge i) Tipping bucket type ii)Weighing type ii)Weighing type iii) Floating type iii) Floating type

Nonrecording raingauge Nonrecording raingauges are most widely used in India. Nonrecording raingauges are most widely used in India. They are known as Nonrecording type because they do not record the rain, but only collect the rain. They are known as Nonrecording type because they do not record the rain, but only collect the rain. The collected rain is then measured by means of graduated cylinder, so as to directly represent the rainfall volume in cm of water depth. The collected rain is then measured by means of graduated cylinder, so as to directly represent the rainfall volume in cm of water depth.

Funnel Metal Container Collecting Bottle GL Concrete Block 600 X 600 X 600

Symon’s type raingauge the Symon’s type (shown in fig) was most widely used in India till the Symon’s type (shown in fig) was most widely used in India till Indian Meteorological Department has adopted this model called Standard gauge for their use at all rainfall stations in this country. Indian Meteorological Department has adopted this model called Standard gauge for their use at all rainfall stations in this country. Such a raingauge consists of a collector, with gun metal container, a base, and a polythene bottle. Such a raingauge consists of a collector, with gun metal container, a base, and a polythene bottle. Both collector and the base are made of fibre glass reinforced polyester. Both collector and the base are made of fibre glass reinforced polyester.

Recording raingauge Recording type raingauges are those raingauge which can gives us a permanent automatic rainfall record without any bottle reading. In this type of a gauge, a man has not to go to the gauge to measure or to read to amount of rain fallen. There is mechanical arrangement by which the total amount of rain fallen, since the record was started, get recorded automatically on a graph paper.

Tipping bucket type Rain Water Circular Collector Funnel Two Compartment Tipping Bucket Reservoir Measuring Glass

Tipping bucket type In Tipping bucket gauge, the rain water is first caught in a collector and then passed through a funnel. In Tipping bucket gauge, the rain water is first caught in a collector and then passed through a funnel. The funnel discharges the water into a two compartment bucket. When 0.25 mm of rain water gets filled up in one compartment, the bucket emptying into a reservoir, and moving the second compartment into the place beneath the funnel, as shown in fig.3.3. The funnel discharges the water into a two compartment bucket. When 0.25 mm of rain water gets filled up in one compartment, the bucket emptying into a reservoir, and moving the second compartment into the place beneath the funnel, as shown in fig.3.3. In this gauge, rainfall measurements are directly recorded at the control room by using electrically driven pen. In this gauge, rainfall measurements are directly recorded at the control room by using electrically driven pen.

ii)Weighing type Rain Water Collect or Platform Or Pan Weighing Mechanism Recording Pen Graph Paper Wrapped Round A Rotating Drum

Weighing type The weighing type gauge weighs the rain which falls into a bucket placed on the platform of a spring or lever balance or any other weighing mechanism as shown in fig.3.4. the increasing weight of the bucket helps in recording the increasing quantity of collected rain, with time, by moving a pen on a revolving drum. The weighing type gauge weighs the rain which falls into a bucket placed on the platform of a spring or lever balance or any other weighing mechanism as shown in fig.3.4. the increasing weight of the bucket helps in recording the increasing quantity of collected rain, with time, by moving a pen on a revolving drum. Such gauges are generally not use in India though they are widely used in USA. Such gauges are generally not use in India though they are widely used in USA.

Drum Pen Carrier PenPen Float Rod Thumb Nut Float Chamber Float Strip Hexagon al Nut Washer Syphon Chamber Discharge Tube Top Cap Glass Disc Small Opening Guide Collar Entrance Tube Set Screw Filter

Floating type Various types of Float recording gauges are in use these days. In such a gauge, the rise of floating body due to the increasing rain catch, helps in lifting the pen point, which goes on recording the rain with time on a graph paper wrapped round a rotating drum. Various types of Float recording gauges are in use these days. In such a gauge, the rise of floating body due to the increasing rain catch, helps in lifting the pen point, which goes on recording the rain with time on a graph paper wrapped round a rotating drum. It is most widely used in India and is popularly called Natural Syphon Recording rain-gauge. It is most widely used in India and is popularly called Natural Syphon Recording rain-gauge.

Artificial rain Sometimes it does not get cold enough in the cloud for condensation to occur. But if we want the cloud to rain, we have to create places where condensation can occur. This is done by a method called cloud seeding. Particles of silver iodide are sprayed on a cloud from an aeroplane. Sometimes, solid carbon dioxide (called dry ice) is used, as it is cheaper. The particles attract water drops from the cloud. When they form a drop that is large enough, it starts raining.