TEMPARATURE

                                           Forms of Precipitation

 1) Fog:-

           

           Dew and frost are forms of condensation that develop near the ground. fog has less climatological importance than clouds and precipitation plays an important role in human affairs fog at Sea makes navigation difficult when warm humid air moves over a cold surface then condensation starts on a small-scale cold night and a clear sky is an ideal condition for fog slight air movement is required for the development of Fog,

         When condensation starts on a small scale moisture is converted into very small droplets so the visibility of the atmosphere is very poor. It is called Fog, Fog is always short-lived. In the morning Fog droplets are disappear because they evaporated by warm air. 

 

2) Rain:-

 

       Rain is a very common form of precipitation. when air moves upward its temperature and holding capacity of moisture decrease. Relative humidity increased. Then the air is saturated after that condensation starts and clouds form when the droplets in the ground in the form of rain.

 

3)Snow:-

 

     For the development snow required sufficiently low temperatures at the time of condensation when moisture-laden air moves upward and reaches at or below freezing point then moisture is converted into a direct ice-crystal hexagonal shape. crystal formed in clouds, especially in Cirrus clouds.

  

4) Hail:-

 

          Hail is a form of precipitation that develops and falls from high-altitude Cumulonimbus clouds. The condensation takes place and small droplets of water are formed in the lower part of the cloud. There is a strong rising convection current of air that can carry the raindrops at higher levels up to a freezing point. Here these droplets freeze and make ice pellets These pellets grow in size. water vapor freezes directly on them as ice crystals (Hail-stone). These hail stones have a weight of about one kg. It consists of concentric layers of ice alternating with layers of snow

  

5) Sleet:-

             According to American terminology, sleet means a form of precipitation. containing small pellets of transparent ice. They are 5m.m or less in diameter. When rain falls to the earth passes through the layer of cold air and freezes. These ice pellets rebound when they strike a hard surface.

Sleet is commonly associated with showery conditions in unstable.

                                                     Types Of Rainfall

Rainfall is the most common form of precipitation. all the precipitation. All the precipitation of the world is due to the condensation process. When air is saturated and cools down moisture is converted into liquid form and then cloud formation takes place and rainfall is the result.

      According to the way the cooling of warm, moist air takes place, rainfall is classified into three types.

1) Convectional rainfall:-

Occurs due to thermal convectional currents due to intense heating of the surface.

2) Orographic:-

  Occurring due to forcibly ascent air by mountain barrier.

3) Cyclonic:-

Occurs due to upward movement of air by convergence of air masses.

1) Convectional:-

  A) This type of rainfall is associated with cumulonimbus clouds.

  B) Rainfall causes to vertical movement of moisture-laden air.

  C) Air moves upward because surface air is heated by vertical sun rays and expands forced to rise.

 D) When air moves upward rapidly cool down. Air because saturated beyond the condensation. 

       condensation starts and a large amount of cumulo-Nimbus is formed. 

                

            

     E) This process occurs on a hot humid summer afternoon when surface heating is intense Cumulus-Nimbus clouds form several miles in vertical.

      F) They give abundant rainfall in the form of heavy showers. Because these clouds cover relatively small areas and quickly drift this type of rainfall is more intense than others with this rain thunder and hailstones are common things.

G) Convectional rainfall comes in the form of heavy showers so less effective for crops maximum water goes in the surface run-off.

H) On the other hand, in mid and higher latitudes convectional rain comes in the warm season. When vegetation is active, and crops are growing. So, it is most effective. 

               This type of rainfall occurs throughout the year in the equatorial region. Where constant high temperature and humidity produce this type of rainfall almost every day. 

2) Orographic: -

     

        Sometimes air is forced to rise due to physical barriers such as mountain escarpments and high hills in the path of extensive airmass. Then large-scale condensation takes place and abundant rainfall is the result called, "Orographic rainfall".

       Maximum rainfall in the world occurs where mountain barrier lies across the path of moisture-bearing winds a famous example is "Cherapunji"(1200c.m)

           In this type of rainfall large amount of rainfall occurs on the windward side. But the leeward side. Where air descending and warming. So becomes drier and gives less rainfall This area is known as the" Rain shadow area"

          The ideal condition for Orographic rainfall is a high and continuous mountain barrier that lies close to the coast and warm moist wind meets the barrier at a right angle.

     Orographic rainfall is less seasonal and daily periodic than convectional In monsoon regions rainfall is maximum when the moisture-laden air moves from sea to land in the summer. orographic rainfall may occur in any season.

3)  Cyclonic Rainfall:-

       This type of rainfall is caused by large-scale vertical motion of air associated with a low-pressure system. Precipitation is moderately heavy and continuous and affects large areas.

    Cyclonic rainfall is not as intense as convectional but it has a longer duration.

     Frontal rainfall is produced when two airmasses have different properties and converge. In many convergence zones especially in mid-latitude two airmasses convergence having different temperature humidity than warm moist air-mass is forced to rise so gives rainfall. It is less violent than a thunderstorm but more widespread steadier and longer duration.