Answer the following questions in about 150 words.

(i) Discuss the salient features of the world distribution of precipitation.

(ii) What are forms of condensation? Describe the process of dew and frost formation.

(i) The following constitute the salient features of world distribution of precipitation:

• Rainfall decreases as we move from equator to higher altitudes.

• The coastal areas and water bodies themselves receive greater amount of rainfall than the interior areas of landmasses.

• Between 35 degrees north and 40 degrees north, the rainfall is received due to easterlies, which leads to higher precipitation along the eastern coasts than the western counterparts. However, due to the flow of westerlies in 45 degrees to 65 degrees north, the trend is reversed.

• Mountains act as barriers to the flow of wind, and cause rainfall on the windward side, leaving the leeward side sans rain.

(ii) The various forms of condensation are:

• Frost

• Clouds

• Dew

• Fog

Formation of Dew: Dew is formed when water vapour condenses over surfaces like grass and leaves. Clear sky, warm air, high relative humidity and cold, long nights help in the formation of dew. Usually, the dew point must be higher than the freezing point of water for this purpose.

Formation of Frost: Frost forms on cold surfaces when condensation occurs below the freezing point. Consequently, the deposition is in the form of ice crystals instead of water droplets. The air needs to fall to a temperature below freezing point for this to occur.