Temperature is a measure of how hot (or cold) a thing is. We measure temperatures with thermometers to give us the numerical value that we know as temperature. The major units of measuring temperature are Celsius and Fahrenheit.
Factors Controlling Temperature Distribution
The variations of climate are controlled by the size, shape and altitude of the land-masses, the extent of land and water, by latitude, distance from the sea, the surface orientation of the country towards the sun, by ranges of mountains covering or shut off from the flow of air masses, by local winds.
The temperature of air at any place is influenced by (i) the latitude of the place; (ii) the altitude of the place; (iii) distance from the sea, the air- mass circulation; (iv) the presence of warm and cold ocean currents; (v) local aspects.
The latitude: The temperature of a place depends on the insolation received. It has been explained earlier that the insolation varies according to the latitude hence the temperature also varies accordingly.
The altitude: The temperature generally decreases with increasing height. The rate of decrease of temperature with height is termed as the normal lapse rate. It is 6.5°C per 1,000 m.
Distance from the sea: Another factor that influences the temperature is the location of aplace with respect to the sea. Compared to land, the sea gets heated slowly and loses heat slowly.
Air-mass and Ocean currents: Like the land and sea breezes, the passage of air masses also affects the temperature. The places, which come under the influence of warm air-masses experience higher temperature and the places that come under the influence of cold air- masses experience low temperature.
Distribution of Temperature
Fields of meteorology and climatology study the statistical distribution of temperature in the atmosphere, on the Earth’s surface and in connection with its spherical shape.
The global distribution of temperature can well be understood by studying the temperature distribution in January and July.
The Isotherms are lines joining places having equal temperature. Northern hemisphere the land surface area is much larger than in the southern hemisphere. Hence, the effects of land mass and the ocean currents are well pronounced.
In January the isotherms deviate to the north over the ocean and to the south over the continent. This can be seen on the North Atlantic Ocean. The presence of warm ocean currents, Gulf Stream and North Atlantic drift, make the Northern Atlantic Ocean warmer and the isotherms bend towards the north. Over the land the temperature decreases sharply and the isotherms bend towards south in Europe.
It is much pronounced in the Siberian plain. The mean January temperature along 60° E longitude is minus 20° C both at 80° N and 50° N latitudes.
