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The Hydrosphere


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The Hydrosphere

  1. 1. WATER ON EARTH The Hydrosphere
  2. 2. OCEANS - 97% of Earth's Water <ul><li>97% water </li></ul><ul><li>2.7% sodium chloride (NaCl) </li></ul><ul><li><1% other &quot;salts&quot; </li></ul>
  3. 3. Salinity <ul><li>A measure of the dissolved salt in water </li></ul><ul><ul><li>35 g of salt per kg of ocean water </li></ul></ul><ul><ul><li>concentration of salt varies with location </li></ul></ul><ul><li>Water dissolves salts & minerals from the soil as it passes over/through the ground </li></ul><ul><ul><li>lakes & rivers: have salts too, but are carried away with the water in the hydrologic cycle </li></ul></ul><ul><ul><li>Great Salt Lake has no outlet </li></ul></ul><ul><ul><ul><li>water only leaves through evaporation </li></ul></ul></ul>
  4. 4. Ocean Currents <ul><li>Surface currents: influenced by air currents above </li></ul><ul><ul><li>Move in same direction as global winds (clockwise in N hemisphere, counter-clockwise in S hemisphere) </li></ul></ul><ul><li>Deeper currents : flow due to water temperature differences </li></ul><ul><li>Currents affect climate by creating warm, moist air masses above them </li></ul>
  5. 5. GLACIERS & ICEBERGS - 2% of Earth's Water <ul><li>Majority of Earth's freshwater </li></ul><ul><ul><li>Glaciers: rivers of slow-moving ice </li></ul></ul><ul><ul><li>Icebergs: chunks of broken-off glaciers </li></ul></ul>
  6. 6. Glaciers <ul><ul><li>Valley glaciers move down mountainsides </li></ul></ul><ul><ul><li>Continental glaciers (ice sheets) flow outward in all directions from a central point </li></ul></ul><ul><ul><li>Typically move 1 - 3 meters each day </li></ul></ul><ul><li>Years of continual snows compress layers below </li></ul><ul><ul><li>Firn (hard-packed ice) </li></ul></ul><ul><ul><li>Polar or high-altitude areas </li></ul></ul><ul><li>Thick layers get heavy/dense </li></ul><ul><li>Insulated bottom layer melts </li></ul>
  7. 7. Continental Glacier Ice Shelf Calving
  8. 8. Flowing Ice <ul><li>Carve valleys by scouring mountainsides </li></ul><ul><li>Pick up, carry & deposit rocks </li></ul><ul><li>Crevasses form when glaciers move quickly (up to 30 m/day) </li></ul><ul><li>Retreat : melting occurs faster than snow accumulates </li></ul>
  9. 12. Icebergs <ul><li>Glaciers reaching seas/lakes float on top </li></ul><ul><ul><li>Ice Shelf = portion of connected glacier floating on water (may be miles wide/long) </li></ul></ul><ul><ul><ul><ul><li>Large chunks break away into icebergs </li></ul></ul></ul></ul><ul><ul><ul><ul><li>90% of iceberg remains below water surface </li></ul></ul></ul></ul>
  10. 13. Ice Ablation <ul><li>Growler = little chunk (<1m) </li></ul><ul><li>Bergy bit = 1 - 5 meters across (3 to 16 feet) </li></ul><ul><li>Small iceberg = 5 - 15 meters across (16 to 50 feet) </li></ul><ul><li>Very large = over 75 meters across (250+ feet) </li></ul>
  11. 14. GROUNDWATER & SOIL MOISTURE - .7% of Earth's Water <ul><li>95% of the water humans use </li></ul><ul><li>Gravity pulls water down </li></ul><ul><ul><li>deeper underground </li></ul></ul><ul><ul><li>out to rivers/lakes/oceans </li></ul></ul>
  12. 15. SURFACE FRESHWATER - .01% of Earth's Water <ul><li>Smallest source of potable water on Earth </li></ul><ul><li>Portland's water comes from Bull Run reservoir </li></ul><ul><ul><li>Mt. Hood surface runoff </li></ul></ul><ul><ul><li>dams built late 1800s </li></ul></ul>
  13. 16. Pure Water <ul><li>150 gallons/day American average </li></ul><ul><ul><li>(includes water used for production of goods we commonly consume) </li></ul></ul><ul><li>Needed for survival: </li></ul><ul><ul><li>3 gallons/day </li></ul></ul>
  14. 17. WATER POLLUTION <ul><li>Open dumping of waste/litter </li></ul><ul><ul><li>industrial legislation has helped </li></ul></ul><ul><li>Groundwater contamination: </li></ul><ul><ul><li>pesticides & fertilizers </li></ul></ul><ul><ul><li>gasoline (storage tanks, oil spills ) </li></ul></ul><ul><ul><li>landfills (mercury, human waste, battery acid) </li></ul></ul><ul><ul><li>hard to test/monitor sources </li></ul></ul><ul><ul><li>flooding/natural disasters </li></ul></ul><ul><li>Thermal water pollution </li></ul><ul><ul><li>water for cooling machinery raises temperatures when discharged back into lakes/rivers </li></ul></ul><ul><ul><li>upsets balance of entire ecosystem </li></ul></ul>
  15. 18. ATMOSPHERIC MOISTURE - .001% of Earth's Water <ul><li>Humidity - water vapor </li></ul><ul><li>Condensation - dew/fog/clouds </li></ul><ul><li>Precipitation - rain/snow/hail </li></ul>
  16. 19. Humidity <ul><li>Absolute humidity : tells the amount of moisture in the air </li></ul><ul><ul><li>warm air holds more water vapor than cool air - why? </li></ul></ul><ul><ul><li>example: absolute humidity of 17.3 mg/L at 20 o C </li></ul></ul><ul><li>Relative humidity - tells how much water the air is holding compared to the most it could hold at a certain temperature </li></ul><ul><ul><li>50% humidity means the air is holding half of the moisture it is able to hold at that temperature </li></ul></ul>8.7
  17. 20. Dew <ul><li>Ground-level condensation </li></ul><ul><ul><li>vapor condenses into liquid droplets as it touches cooler ground surfaces </li></ul></ul><ul><li>Dew Point = temp. at which atmospheric vapor condenses </li></ul><ul><ul><li>varies depending on the humidity (how much vapor is in the air) </li></ul></ul>
  18. 21. Clouds <ul><li>Suspended ice crystals or water droplets </li></ul><ul><ul><li>reflected sunlight causes whiteness </li></ul></ul>
  19. 22. Fog <ul><li>Ground-level clouds </li></ul><ul><ul><li>high humidity (  water vapor) + quick cooling of surface air </li></ul></ul><ul><li>Photochemical fog = formed in very dirty or dusty air (smog) </li></ul><ul><ul><li> condensation nuclei =  water droplets formed </li></ul></ul>