Different factors which control the
temperature on the earths Surface:
The temperature differs not only
from place to place but it also differs at the same place from time to time
because it is closely related to insolation. The factors which influence the
temperature are:
1.Latitude(Why
Africa is hotter than siberia in Asia? Why is the Torrid Zone hotter than the
Frigid Zone?)
- latitude means distance from the Equator.
- The nearer to the equator the more the heat from isolation is received. In low latitudes the Sun's rays strike at more direct angle while at the higher latitudes the rays strike the surface more obliquely.
- Oblique rays pass through greater distance and lose much of their heat.
- That is why Equatorial lands of Africa are hotter than those of Siberia in Asia.
- We can say that temperature decreases with the increase in latitude.
Why plateaus are
warmer than Equator?
Why mountains are
cooler at top than foot? Why mountain peaks are covered with snow?)
- The temperature decreases with the increase in height. It is the Earth's surface that heats the lower layers of the air to a great extent.
- So the temperature decreases as we move higher above the Earth's surface.
- Again, the air near the surface is denser and it becomes thinner as we go higher and higher. As a result, it is less warm as we go upward. The higher the place above the sea level, the cooler it is.
- for every 165 meters of altitude or height the temperature is reduced by 1°C. That is why plains are warmer than plateaus and plateaus are warmer than mountains. Mountains are cooler at the top of the mountain than at its foot.
- Mountain peaks at the Equator may be snow-covered throughout the year. It is all due to the high altitude. That is why mountains are cooler than the plains.
- The land gets heated and cooled more quickly than water. So water bodies have impact on the places close to it.
- In summer the land gets more warmer than the sea and the onshore winds begin to blow towards the land and which brings a cooling effect on lands near the sea. Thus, the summer is not very hot in areas near to water bodies
- While land loses heat quickly in winter and becomes cooler when compare to seawater. Then the warm sea keeps the areas near the shore quite warm and winter is not so cold there. Such a climatic is called the Equable Climate or the Maritime Climate.
- It is neither very hot nor very cold.
- Places which are nearer the sea have a very small range of temperature.
- The areas situated away from the sea shore do not have this benefit. As a result, summers in those areas arc very hot and winters arc very cold. Cities like Delhi and Nagpur have such an extreme type of climatic or Continental Climatic.
- Here the range of temperature is great.
4. Ocean Currents(why oceans are called Rivers in the Sea) (how do ocean currents influence the temperature on the earth)
Big streams of water flowing
regularly, constantly and in definite direction on the surface or sub-surface
of the ocean are called Ocean Currents.
When they are produced, the water of
the ocean moves from one part to another. Hence Ocean currents are called "Rivers in the sea".
These currents are often swift and narrow with a speed varying from two to
ten kilometres per hour.
What is Drift?
If the mass of water moving on the surface or
sub-surface of an ocean is broad, slow and shallow, it is termed as drift. Its
speed varies from 1 to 3 kilometres per day.
There are two types of currents:
Warm currents and the Cold currents.
The warm currents flow from low latitudes
(or Equatorial regions) towards the high latitudes (or Poles) while the cold
currents flow from high latitudes (or Poles) to low ones (or equitorial
regions).
These phenomena cause a general circulation of ocean waters.
Ocean currents exert influence on
the temperature of various places in a number of ways.
(i) Ocean currents exert influence
on the climate of
the coastal regions.
Warm currents raise the temperature the cold currents lower
the temperature.
Example: cold
current of Oyashio makes the winters longer and more severe in northern Japan
Warm current of Kuroshio warms the climate of southern Japan.
ii. Countries influenced by warm currents
receive more rainfall because
winds passing over them absorb a lot of moisture. (explain why hot deserts are found near the coastal areas)
Britain. Ireland and Eastern
U.S.A. receive such rains due to warm currents (North Atlantic Current in
respect of Britain and Ireland, and the Gulf Stream Current in respect of
U.S.A.)
Winds passing
over cold currents are dry and cold and do not cause rain. That is why hot
deserts are found near the coastal areas which are washed by cold currents.
iii. Infulence on Trade: Warm currents help the harbours in cold countries remain open all the year round and so trade can be carried on throughout the
year. For example, the harbours of Great Britain and Norway remain open all the
year round on account of the warm Gulf Stream. On the other hand, the Labrador
coast remains icebound on account of the influence of the cold Labrador
Current
iv. Influence on navigation: Ships sailing along a
current pick up greater speed. They can save time and fuel also. But ships
sailing against a current are slowed down
v. Warm currents help navigation by melting the dangerous icebergs.
vi. The best fish are found in cold and shallow waters.
The cold currents carry the fish to warmer regions and promote fish trade
vii. Dense fogs are produced where cold and warm
currents meet together. Such fogs reduce visibility, so they prove very dangerous
for the ships.
5. Winds:
- Cold and warm winds also affect the temperature of a place.
- Winds from warmer regions increase the temperature whereas winds from the colder regions reduce it.
- Sea breezes reduce the temperature of the coastal regions in the afternoon.
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1 comment:
Very helpful..thanks a lot
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