The hydrological cycle

• Water stores

  A) Oceans

  B) Ground ice and permafrost

  C) Glaciers and ice caps

  D) Groundwater

  E) Lakes

  
• Stores


  Stocks of water, places where the water is held. For example, oceans.
• Fluxes


  The measurement of the rate of flow between the stores.
• Processes


  The physical factors which drive the fluxes of water between stores.
• The hydrological cycle is a closed system

  • No water is added to global budget and none is removed
  • No inputs occur from outside and nothing is lost
  • Two processes - solar and gravitational energy
  • More evaporation occurs as global climate warms which increases moisture levels in the atmosphere, leading to greater precipitation
  • Gravitational potential energy keeps water moving through the system in a sequence of inputs, outputs, stores and flows
• Water stores


  In cubic km:

  • Oceans - 1,335,000,000 (96.9%)
  • Icecaps - 26,350,000(1.9%)
  • Groundwater - 15,300,000 (1.1%)
  • Rivers and lakes - 178,000 (0.01%)
  • Soil moisture - 122,000 (0.01%)
  • Atmospheric moisture - 13,000 (0.001%)
• Why is the atmosphere the smallest water store?

  When it becomes too saturated, it rains and is moved to a different store.
• Flows and fluxes


  In cubic km per year:

  • Oceans and atmosphere
  • Evaporation 400,000
  • Precipitation 370,000
  • Atmosphere and landmasses
  • Evaporation 60,000
  • Precipitation 90,000
  • Landmasses and oceans
  • Surface runoff 30,000