EES 3 News

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EES 3 News

• No news is no news

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Lecture 5 Hydrosphere

• Hydrosphere
• Components (oceans, groundwater, glaciers, ice,
  and lakes)
• Hydrologic cycle
• Groundwater issues
• Phenomena relevant to climate

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Definitions, 1

• Hydrosphere water on Earths surface and
  near-surface
• Important Reservoirs
• atmosphere
• oceans, freshwaters
• glaciers
• biosphere
• groundwater

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Definitions, 2

• Hydrologic Cycle movement of water on surface
  (between reservoirs). Earths water balance.

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Hydrologic Cycle

• Largest chemical transfer on Earth
• Heat transfer, equator to poles
• Moderates climate

• Agent of erosion
• Critical to biosphere
• In balance evaporation precipitation

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Wheres the Water?
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Residence Times for Fresh Water
residence time reservoir/flux
explanations?
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Groundwater Basics

• Groundwater is all the water stored (at least
  temporarily) beneath the surface of the Earth
• In pores and fractures (not underground
  streams) aquifers
• Two main sources for groundwater
• Rainfall/snowfall
• Glaciers
• Much existing groundwater amounts to fossil
  water
• only sometimes a renewable resource

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Why Groundwater is Important

• Major source of drinking water (50)
• Major source of irrigation water (40)
• Resource for industrial use (25)
• Recharges rivers and streams
• Agent of erosion, biogeochemistry

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Groundwater Issues

• Depletion of a non-renewable resource
• Contamination
• Water-table drawdown
• subsidence (Houston)
• salt-water encroachment (coastal areas)

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Ogallala Aquifer

• 200 feet thick (range is 1-2000 feet)
• water would cover 50 US states to depth of 1.5
  feet if spread out evenly
• supports 20 billion per year in food and fiber
  production
• use rate is at least 10X recharge rate
• has dropped up to 10 feet/year

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Water-Table Drawdown

• fresh/salt water boundary controlled by fresh
  water flow

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Sea Ice

• Insulation of ocean from atmosphere
• Salt exclusion
• Ice floats!
• Albedo effects

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Mountain Glaciers

• more than piles of ice glaciers are incredibly
  dynamic (and dangerous!)
• Important agents of erosion
• Important source for local climate records

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Ice Sheets

• Antarctica today large parts of Europe and N.A.
  at last glacial maximum

• Up to 4 km thick
• Important part of climate system
• Feedbacks through albedo, sea level, isostasy,
  regional climate, and more