This document discusses rainfall, including its definition, formation process, measurement, and factors that affect rainfall amounts. Rainfall occurs when water vapor in the atmosphere condenses into droplets too heavy to remain suspended. It is part of the water cycle as water evaporates from bodies of water, rises into clouds, condenses, and precipitates as rain or other forms of precipitation. Rainfall is measured using rain gauges, which must be placed level and in open areas according to standard considerations. Factors that influence rainfall amounts include latitude, temperature, moisture levels, frontal activity, heating effects, mountain barriers, and the distribution of land and water masses.

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WARM WISHES BY-: KRITIKA MA’AM

2. RAINFALL
DEFINATION
FORMATION OF RAIN
SIZE & INTENSITY OF RAIN
TYPES OF RAINFALL
MEASUREMENT OF RAINFALL
MEASUREMENT OF FACTORS
AFFECTING THE AMOUNT OF RAINFALL
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4. RAINFALL IS A FORM
PRECIPITATION.
IT OCCURS WHEN WATER
VAPOUR IN THE ATMOSPHERE
CONDENSE INTO DROPLETS
THAT CAN NO LONGER BE
SUSPENDED IN THE AIR.
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6. THIS PROCESS IS ALSO CALLED WATER
CYCLE OR HYDROLOGICAL CYCLE
1. WATER IN THE WATER BODIES EVAPORATES
DUE TO THE HEAT ENERGY PROVIDED BY
SOLAR RADIATION.
2. THE WATER VAPOUR MOVES UPWARDS AND
FORMS CLOUDS.
3. WHILE MUCH OF THE CLOUDS CONDENCE
AND FALL BACK TO THE OCEANS AS RAIN, A
PART OF THE CLOUDS IS DRIVEN TO THE
LAND AREAS BY WINDS.
4. THERE THEY CONDENSE AND PRECIPATATE
ONTO THE LAND MASS
RAIN,SNOW,HAIL,DRIZZLE etc.
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9. SIZE OF RAINFALL
MINIMUM SIZE OF RAINFALL
IS 0.5 mm
MAXIMUM SIZE OF
RAINFALL IS ABOUT 6.0mm
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10. INTENSITY OF RAINFALL
TYPE INTENSITY
LIGHT RAIN UP TO 2.5 mm/hr
MODERATE RAIN 2.5 mm/hr to 7.5
mm/hr
HEAVY RAIN >7.5 mm/hr
VIOLENT RAIN >50 mm/hr
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12. THREE TYPES OF RAINFALL ARE
1.CONVECTIVE RAINFALL
2.OROGRAPHIC RAINFALL
3.FRONT OR CYCLONE
RAINFALL
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13. CONVECTIVE
RAINFALL
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A PACKET OF AIR WHICH IS
WARMER THEN THE
SURROUNDING DUE TO LOCALIZED
HEATING RISES UPWARDS AND
CONSEQUENTLY UNDER GO,
COOLING,CONDENSTION AND
PRECIPITATION.

14. OROGRAPHIC RAINFALL
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THE MOIST AIR GET LIFTED UP TO
HIGHER ALTITUDES DUE TO THE
PRESENCES OF THE MOUNTAIN
BARRIERS UNDER GO,
COOLING,CONDENSTION AND
PRECIPITATION.

15. FRONTIAL RAINFALL
WHEN TWO AIR MASSES MEET THEY DO NOT
MIX READILY DUE TO THE DIIFERENCES IN
TEMPRATURE AND DENSITY. IN FRONT
THERE IS LIKE AN IMAGINARY LINE
SEPRATING TWO CONSTRASTING AIR
MASSES.
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17. The rainfall is collected and measured in a rain gauge.Terms such as
piiviometer , or barometer and iyeometer are also sometimes used to
designate a rain gauge.For setting a rain gauge the following
consideration are important:
1.The ground must be level and in the open and the instrument present a
horizontal catch surface.
2.The gauge must be set as near the ground as possible to reduce2wind
effects but it must be sufficiently high to prevent flood.
3.The instrument must be surrounded by an open fenced area of at least 5.5
mm X 5.5 m.
4.No object should be nearer to the instrument than 30 m or twice height of
the obstruction.
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18. Raingauge can be broadly classified into two categories-
NON RECORDING GAUGES-
Symon's Gauge
RECORDING GAUGES-
Tipping Bucket Type
Weighing Bucket Type
Natural Syphon Type
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20. FACTORS WHICH EFFECT THE AMOUNT
OF RAINFALL ARE
1. LATITUDE
2.Temperature
3.Moisture Air
4.Masses Frontal
5.Activity Differential
6.Heating
7.Mountain Barrier
8.Distribution of Land & Water
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