Humidity and Rainfall

Relative Humidity
1. a.k.a RH
2. proportion of water vapour in the air inrelation to the maximum amount of air can hold at a given temperature
3. expressed as percentage
4. saturation is 100% RH
5. saturation occurs when there is max amout of water vapour in the air
6. Evaporation is not possible when the air is saturated
Precipitation
1. refers to any water falling from the atmosphere to the earth's surface
2. 2 types of rain : convectional and relief rain
3. 1. Clouds are made up of water droplets
4. 2. These water droplets combine to form big water droplets.
5. 3. The big water droplets became too heavy and fall as rain.
Convectional rain
1. 1. Intense insolation -> rapid evaporation
2. 2. Large quantity of water vapour rises rapidly -> condensation -> clouds
3. 3. Cumulonibous clouds -> anvil / mushroom shaped
4. 4. Heavy downpour over a short duration within a small area, thunder and lightning are common
Relief rain
1. Occurs when heavy moist air is forced up a landform of higher altitude by winds
2. 1. When moist air rises, the surrounding temperature falls -> rising RH and promotion of condensation
3. 2. Clouds cannot hold the heavy water droplets -> rain on the windward side
4. 3. clouds pass over the mountains, most moisture released -> dry air
5. 4. Leeward side -> no rain -> rain shadow
Atmospheric pressure
1. Atmospheric (air) pressure is the weight of the air exerted on the earth"s surface
2. Dependent on temperature and altitude
3. Lower temperature -> air molecules packed closer -> greater weight exerted per unit are -> higher air pressure
4. Low land -> low altitude -> more air above -> higher air pressure
5. Movement of air from high pressure to low pressure
Land and Sea breezes
Climate types
1. Tropical/Equatorial climate
  1. Found within 10 degrees of Equator
  2. Natural vegetation : Tropical rainforest, mangroove
  3. High mean annual temperature of 27 degrees
  4. No distinct wet or dry season -> rain throughout the year
  5. Relative humidity of >80%
  6. High annual rainfall of 150 to 300cm
  7. Convectional rain is common
2. Polar climate
  1. Summer temperature is about 5 to 10 degrees
  2. Winter temperature stays below -15 to 20 degrees
  3. Large annual temperature range
  4. Precipitation - mainly snow, only rain in short summers
  5. Polar climate cover 20% of Earth
  6. Lack warm summers, have long winters
  7. Days are short, nights are long
  8. Strong cold winds
  9. Treeless tundra, very little vegetation
3. Cool temperate climate
  1. Found within 35 to 70 degrees
  2. Large variation in climatic data
  3. Low mean annual temperature o 5 to 10 degrees
  4. Large annual temperature range of 20 to 30 degrees
  5. Strong maritime effects on coastal areas
  6. Low moderate annual rainfall of 30 to 200 cm
  7. Precipitation -> rain and snow

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Humidity and Rainfall

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	Created by 7114130298 over 10 years ago