5.2a inputs, flows and outputs

• orographic/relief rainfall

  • warm moist air across ocean rises over an obstacle (mountain)
  • cools and condenses to form clouds + rain
  • causes low pressure as it rises - overcome obstacle with denser air so sinks and creates high pressure
  • creates rain shadow on lee side - little precipitation, cloud cover or wind
  • e.g Pennines in Manchester
• convectional rainfall

  • insolation from sun heats ground up and water in air evaporates
  • rises until dew point where it cools and condenses - loses energy
  • energy transferred to surroundings and heats up nearby water which rises and condenses (latent heat transfer)
  • creates cumulo-nimbus clouds
  • common at equator due to ITCZ e.g Cherrapungi in India receives 3000mm of rainfall in one month in summer
• frontal rainfall

  • creates low pressure environment or a depression
  • different air masses meet - warm air rises over cool air -> rises and condenses
  • most common rainfall in UK
• interception


  temporary storage as water is captured by vegetation before reaching soil - can prevent up to 40% of water reaching ground
• infiltration


  water entering the topsoil - most common during slow or steady rainfall
• Surface runoff


  flow over land surface
• throughflow


  water seeping laterally through soil below surface but above water table
• percolation


  downward seepage of water through rock under gravity, especially on permeable rocks e.g limestone
• groundwater flow

  • water infiltrated and percolates into bedrock and below/at water table
• evaporation


  conversion of water to vapour
• transpiration


  water taken up by plants and transpired onto leaf surface
• channel flow


  movement of water contained within a river channel
• evapotranspiration 


  combined effect of evaporation and transpiration