TEMPARATURE

                                                                  Temperature

The sun is the major source of atmospheric heat the sun. It is heated by the earth from the lower layers to the upper layers. There are many processes by which the atmosphere is heated. 

                1) Radiation:- 

                                    Radiation main processes and cooling of the atm. It is the process of transmission of energy in the form of electromagnetic waves. The solar radiation comes in the form of short waves. It is received by the earth after gaining this heat earth's surface becomes hot and radiated the same amount of energy into the atm by long waves. This heat is easily absorbed by atm.

           2) Conduction:-

               when two bodies of uneven temperature come into contact energy flow starts in the form of heat from a hot body to a cool body. This process of transfer of heat is known as "conduction" This process occurs through molecular movement. Absorbed heat of earth's surface. Air is a poor conductor of heat. So this process is not very important in the process of heating of atmosphere.

         3) Convection:-

                        It is the process of transfer of heat from a liquid or gaseous substance to another by the movement of the substance. Convection is possible only in gas or liquid form. It is impossible in solid substances convection is the most significant mechanism of heat transfer largely earth's heat transfer to the atmosphere by convection.

                                The factors affect the horizontal distribution of  temperature

Horizontal temperature distribution over the earth's surface is shown by the means of isotherms. We can understand many significant facts of thermal distribution over the earth's surface from the isotherms. Here all the temperature fig are reduced to level. So that the effect of altitude is eliminated. However such types of maps are not useful to agriculturists and engineers.

                Isotherms on the map run an east-west trend of isotherms are indicating that latitude is the single greatest cause of temp contract.

                                                                  Factors 

      1) Latitude:-

     The intensity of insolation depends upon the latitude angle of the sun rays and the length of the days at any given place is determined by latitudinal location sun rays are vertical on the equator throughout the year at mid-day sun is overhead in the tropics while the outside side the tropics sun rays are oblique vertical rays are concentrated on a smaller area and passes through less thicker atmosphere so the heating power of vertical rays is more thus tropical area received more energy.

    on the other hand out outside the tropics sun rays are spread over a larger area and travel through a longer distance. Hence much energy is absorbed by clouds water vapor and dust particles. In short, temperature decreases from the equator to the pole.

                                 

   2) Altitude:-

    Temperature decreases with increasing altitude at the rate of 6℃ per 1000M.it is known as the "Normal lapse rate"

 I) Lower layers absorb more heat air expands and rises but in the upper part air is thin and air does not get much heat from radiation.

II)Lower layers are denser and contain much Co2, water vapor, and dust particles so this layer can absorb more in this the tropics' thermal uniformity is disturbed by the height of the area.

III) Distance from Sea:-

       Land and water surfaces absorb heat differently land surface is more quickly heated so the temp increases with increasing distance from the sea due to the land and sea breeze the temp of rise coastal areas is less than in places which are away from the coast having maximum temp 37℃ on the other hand Nagpur is situated 1000k.m.away from the coast having maximum temp 46℃.

                

   

     IV) Slope of  land:-

         The slopes of those mountains that run from east-west have different temperature the sun facing slopes receive more heat than opposite slope because sun rays strike the south facing slopes at a steeper angle.

    V) Nature of soil:-

        

             The colour of the soil also affects the distribution of temperature rocky and sandy soil heated more rapidly and also cool rapidly colour soil receives more insolation than the light colour black colour soil absorbs more heat than white colour.

 VI) Prevailing  Wind:-

           Prevailing winds also affect the temperature distribution. They transport heat from warm to cold areas depending on their thermal characteristics. The winds blowing from the equator to high latitudes increase the temperature of the region where they reach. Polar winds decrease the temp of the region where they reach for example warm Chinook winds increase the temperature of the "Prairie "plain of the U.S.A 

 VII) Ocean Currents:-

  

           There are two types of ocean currents warm and cold. Warm ocean currents decrease the temperature of the land surface along the coastal region. 

         The North Atlantic drift increases the temp of N.W.Europe.  so the coast of the U.K. and Norway do not freeze during the winter Similarly cold currents the temperature of land areas.

  VIII) Cloudiness:-

               The amount of clouds affects the distribution of the temperature. Thick clouds prevent the incoming solar radiation during the day ground radiation during the day and ground radiation at night. Hence region has a clear sky much hotter than the region covered by thick clouds.