1-11: Global Hydrological Cycle

Eugene S. Takle
© 1998

  • A. Importance
    1. Global energy balance
      • a) moving energy from tropics poleward
      • b) vapor as a greenhouse gas
      • c) clouds as reflector of solar, absorber of infrared
      • d) snow/ice cover influence on albedo
      • e) angle-of-incidence dependence of albedo
      • f) impact on absorptivity of shortwave radiation
    2. Regulator of global vegetation patterns
    3. Influence on global and regional ocean circulations
    4. Source of renewable energy
    5. Role in ecosystem functioning
    6. Human consumption
  • B. Components of the global hydrological cycle
    1. Global oceans
    2. Antarctic ice sheet
    3. Greenland ice sheet
    4. Mountain glaciers
    5. Arctic ice
    6. Lakes
    7. Rivers
    8. Sea ice
    9. Continental seasonal snow
    10. Ground water
    11. Soil moisture
    12. Deep aquifers
    13. Permafrost
    14. Biospheric water
    15. Atmospheric water vapor
    16. Clouds - liquid
    17. Clouds - ice
  • C. Reservoirs, fluxes, and time scales
  • D. Spatial distribution
  • E. Phase changes and consequences
    1. Latent heat of vaporization
      • a. (0oC): 2.500 x 106 J kg-1
      • b. (100oC): 2.25 x 106 J kg-1
    2. Latent heat of fusion: (0oC): 3.34 x 105 J kg-1
  • F. Interaction with dynamics
  • G. Role in global change of components of the global hydrological cycle
    1. Global oceans
      • Transport heat poleward
      • Supply moisture to atmosphere
      • Medium for ocean biology
      • Provides thermal inertia to create long time scales in the climate system
      • Source of food
    2. Antarctic ice sheet
      • Reflects solar radiation
      • Provides thermal inertia to create long time scales in the climate system
      • Creates extreme cold conditions for stratospheric ozone depletion
    3. Greenland ice sheet
      • Reflects solar radiation
      • Provides thermal inertia to create long time scales in the climate system
    4. Mountain glaciers
      • Reflect solar radiation
      • Provide a reservoir of freshwater for human consumption
    5. Arctic ice
      • Reflect solar radiation
      • Regulates circulation between Arctic Ocean and Atlantic/Pacific
    6. Lakes
      • Provide fresh water for human consumption
      • Ecosystem services
      • Aesthetics (raise the human spirit)
      • Provide source of food
      • Allow inexpensive transportation
    7. Rivers
      • Provide fresh water for human consumption
      • Economic services (cooling water, industrial uses)
      • Ecosystem services
      • Aesthetics (raise the human spirit)
      • Provide source of food
      • Allow inexpensive transportation
    8. Sea ice
      • Contributes to poleward heat transport
      • Regulates heat loss
      • Reflects solar radiation
    9. Continental seasonal snow
      • Reflects solar radiation
      • Temporary (seasonal) water reservoir
    10. Ground water
      • Human consumption
      • Irrigation
      • Temporary reservoir
    11. Soil moisture
      • Agriculture/forestry
      • Regulate surface energy budget
      • Ecosystem services
    12. Deep aquifers
      • Agriculture
      • Human consumption
    13. Permafrost
      • Storage of methane
      • Thermal inertia
    14. Biospheric water
      • Transports nutrients in plants
      • Cools plants
      • Nourishment for animals
    15. Atmospheric water vapor
      • Greenhouse gas
      • Vehicle for heat transport
      • Vehicle for cloud formation
      • Vehicle for moisture transport
    16. Clouds - liquid
      • Reflect solar radiation
      • Absorb infrared radiation
      • Transport water
      • Transport latent heat
      • Cleanse atmosphere
    17. Clouds - ice
      • Reflect solar radiation
      • Cleanse atmosphere
      • Absorb infrared radiation
      • Transport latent heat
  • F. Major field experiments and data relating to global change
    1. GEWEX
    2. Water resources of the United States