TYPES OF CLOUD

    Cloud is a visible, dense mass of suspended water droplets and ice crystals suspended in the air, generally much above the ground surface.

   

    Clouds are generally formed when air is forced to rise at a front, over mountains, or due to condensation of water vapour around hygroscopic nuclei caused by cooling due to lifting of air, generally known as adiabatic cooling.




TYPES OF CLOUDS.



Luke Howard 1803, first classified the clouds.

   

 He distinguished three principal cloud forms:-


(A) STRATUS CLOUD -


    From Latin stratum = Layer

    (i) It is lying on a level sheet.


(B) CUMULUS CLOUD -


  From Latin, Cumulus = pile.

  (i) Having a flat base and round tops

  (ii) It is lumpy in appearance.


(C) CIRRUS CLOUD -

   

  From Latin Cirrus = hair.

  (i) Having a fibrous or feathery appearance.





There are ten basic types of clouds as given in "The International Cloud Atlas" ( World Meteorological Organisation (WMO) was published the book "The International Cloud Atlas")

   

  The principal types of clouds are:-



HIGH CLOUDS ( ABOVE 7000 METERS)


1. CIRRUS (Ci) -


                       (i) They do not cause rainfall

                       (ii) They are composed of tiny ice crystals.

                       (iii) When cyclones arrive, these clouds are seen first.

                       (iv) It has a silky appearance.

                       (v) It is often called 'mare's tails' and indicates fair weather.




2. CIRROCUMULUS (Cc) -


                          (i) These are thin, white coloured clouds having patches of small white flakes on small globules which are arranged in distinct groups or wave-like form, so-called and appear as sand ripples.



3. CIRROSTRATUS (Cs) -


                (i) Generally white in colour.

                (ii) It spread in the sky like milky-thin sheets.

                (iii) These are transparent clouds.

                (iv) Create Halos around the Sun and the Moon.



MIDDLE CLOUDS ( 2000 TO 7000 METRES)



4. ALTOSTRATUS:-


            (i) These are thin sheets of grey or blue clouds having a fibrous or uniform appearance.

            (ii) The Sun and the Moon are obscured and appear as bright spots behind the clouds when this type of cloud becomes thick.



5. ALTOCUMULUS:-


             (i) It is white and grey wavy layers or globular forms.

             (ii) It is sometimes called a sheep cloud or wool pack clouds.



LOW CLOUDS ( BELOW 2000 METRES ):-


6. STRATUS:-


            (i) These are dense.

            (ii) Fog-like clouds..

            (iii) Dark grey colour.

            (iv) They are composed of several uniform layers, capable of producing only light drizzle.



7. STRATOCUMULUS:-


               (i) These cover the entire sky in the winter season.

               (ii) These are generally associated with fair or clean weather..



8. NIMBOSTRATUS:-


         (i) Dark colour.

         (ii) very close to the ground.

         (iii) They create darkness.

         (iv) These clouds increase the humidity in the atmosphere.

         (v) These are also known as rain clouds.



VERTICAL CLOUDS-



9. CUMULUS:-


    These are dense, widespread and dome-shaped clouds with flat horizontal bases and rounded tops, but it is fair-weather clouds.



10. CUMULONIMBUS:-


      (i) They are heavy, dense and dark with vertical development.

      (ii) This type of cloud's top looks like a cauliflower and often spreads like an anvil.

      (iii) These are referred to as thunder clouds.