This PPT explains the term weather and climate, instruments which are used in Meteorology dept etc...

2. Weather:
weather describes the atmospheric conditions
at a particular place and time together with
change taking place over short term. E.g.
hour-by-hour or day by day.
Climate:
climate is the average weather
conditions of a place or area,
the result of weather data
recorded over a long period of
time (normally 30 years)

3. 
Maximum and minimum thermometer
Wet and dry bulb thermometer
Hygrometer
Barometer
Stevenson's Screen Thermometer
wind vane
Anemometer
Rain guage
Weather station instruments:

4. 
Latitude
Distance from the sea
Prevailing winds
Ocean currents
Altitude
 cloud cover
Factors affecting temperature

5. 
Temperature:
Air temperature is recorded in the shade ( in a
Stevenson’s Screen)
It is recorded using a maximum/minimum
thermometer ( highest and lowest temperatures in
the last 24 hours)
It is recorded in degrees Centigrade (Celsius) or
Fahrenheit.
Solar radiation or insolation, is the main source of
heat energy to the atmosphere
The atmosphere is warmed mainly from long wave
radiation emitted by the earth.
Temperature therefore decreases with height at an
average rate of 6.5°C per 1000 Meter
A Range Of Data Is
Recorded

6. Air pressure:
• Air pressure is the weight of the atmosphere at
the earth’s surface
• Air pressure is recorded using an aneroid
barometer
• It is measured in millibars (mb), reduced to sea
level( average pressure at sea level is 1013mb)
Air pressure varies with:
(1)TEMPERATURE; warmer lighter air is forced to
rise creating areas of low pressure; heavier,
colder air descends creating areas of high
pressure
(2)HEIGHT- As the atmosphere becomes thinner
pressure decrees.

7. Maximum and minimum
thermometer

8. Maximum thermometer is also a
mercury-in-glass thermometer
having a constriction near the bulb
end. When the temperature of air
rises, the mercury in the
thermometer expands and forces its
way into the stem past this
constriction. But when the bulb
cools none of the mercury above
the constriction will get back into
the bulb and then the length of the
mercury remains the same. The
end of the mercury thread farthest
from the bulb registers the highest
temperature reached in a day.

9. Minimum Thermometer:
The liquid used in minimum
thermometer is alcohol in which
a dumb-bell-shaped index is
set. When the temperature
falls, the alcohol column drags
the index towards the bulb end
but when the temperature rises
the alcohol column expands
and runs past the index without
disturbing it. Thus the end of
the index farthest from the bulb
gives the lowest temperature
attained in a day.

10. Wet & Dry Bulb Thermometer:
This instrument will be used to measure
the air temperature
Hygrometer:
This instrument will be used to
measure the humidity (moisture)
in the air

11. Barometer:
A barometer is a
scientific instrument
used in meteorology
to measure
atmospheric pressure.
Stevenson’s Screen Thermometer:

12. Wind Direction:
wind vane is used to recorded as the direction
from which direction wind is blowing
Wind Speed:
Anemometer is used to measure wind speed.
Speed is measured in Knots or kilometers per
hour.

13. PRECIPITATION: (RAIN FALL)
Precipitation mainly occurs when air is
forced to rise.
Precipitation is the deposition of moisture from
the atmosphere as rain drizzle, hail, snow, fog
or dew.
Rainfall is measured by using a RAINGUAGE

14. Characteristics of Stevenson screen:
• Thermometers (and sometimes other instruments) are
housed in a white, louvered box called the Stevenson
Screen.
• It is painted white to reflect incoming radiation from the Sun
and is set at a height of 1.25 metres above the ground, so
as not to be affected by the Earth's low-level radiation. The
screen should be kept clean from dust and dirt.
• In order to prevent direct sunlight falling on and affecting
the instruments when the door is opened it is designed so
that the door opens to the north in the northern
hemisphere. This is because the Sun never shines from the
north.
• The thermometers inside are usually the dry bulb, wet bulb,
maximum and minimum, they are read in that order.

15. Characteristics of Stevenson screen:
• The dry thermometer is a mercury filled
thermometer, recording changes in temperature in
degrees and tenths Centigrade. The temperature
rises and falls as the temperature changes.
• The maximum thermometer is filled with mercury,
which moves up the central tube as the
temperature increases. There is a constriction just
above the bulb of the thermometer, which stops the
mercury returning to the bulb when the temperature
falls. Therefore, the highest temperature (the max)
is recorded regardless of the temperature at the
observation.

16. TYPES OF CLOUDS
The main types of clouds can be separated into three broad
categories according to the height of their base above the ground:
HIGH CLOUDS,
MEDIUM CLOUDS
LOW CLOUDS.
High clouds: are usually composed solely of ice
crystals and have a base between 5500 and 14,000
meter.
There are 3 types of High Clouds
Cirrus
Cirrocumulus
Cirrostratus

17. white filaments
small rippled elements
transparent sheet, often with a halo

18. Medium clouds: are usually composed of water
droplets or a mixture of water droplets and ice crystals,
and have a base between 2000 and 7000 meter.
There are 3 types of Medium clouds
Altocumulus clouds
Altostratus clouds
Nimbostratus clouds

19. layered, rippled elements,
generally white with some
shading
thin layer, gray, allows sun to
appear as if through ground
glass
thick layer, low
base, dark, rain
or snow may fall
from it.

20. Low clouds: are usually composed of water droplets
though cumulonimbus clouds include ice crystals, and
have a base below 2000 meter
There are 4 types of low clouds:
Cumulonimbus clouds
Cumulus clouds
Stratus clouds
Stratocumulus clouds

21. 1. large, cauliflower-
shaped towers, often
‘anvil tops’ something
giving thunderstorms,
or showers of rain or
snow.
2.individual cells,
vertical rolls or towers,
flat base
3.ayered, uniform base, grey
4. layered,
series of
rounded rolls,
generally white
with some
shading.

25. BY:
Suresh Kumar Kundur