Hydrologic Cycle

WATER, LIFE & CLIMATE

PART I: WATER IS LIFE

WATER IS LIFE

YOU are 60% water and can only live a few days without drinking water

WATER & CULTUREIndigenous cultures “recognize, honor and respect water as sacred and sustains all life”

Water is worthy of reverence and great respect

www.indigenouswater.org/user/IPKyotoWaterDeclarationFINAL.pdf

Water is the blood of mother earth, the giver of life

http://www.youtube.com/watch?v=QTMeECg1HDU



http://www.indigenouswater.org/user/IPKyotoWaterDeclarationFINAL.pdf

WATER & CULTUREWater plays a central role in most indigenous cultures

There is a Tohono O’odham song that describes how the red ripe fruit of the saguaro call to the clouds to form overhead. These clouds mark the beginning of the summer monsoons and also the beginning of the new year in the traditional Tohono O’odham calendar

WATER AND SOCIETY

Water shortage predicted to become THE major crisis in our futureOver 50% of the world’s population does not have

an adequate supply of safe drinking water

WATER & SOCIETYWater shortages are due to the growing human population on Planet Earth

Human Population HistoryWATER & SOCIETY

PART II: HYDROLOGIC CYCLE

HYDROLOGY Water distribution

70% of the Earth’s surface is covered with water

HYDROLOGY Water distribution

70% of the Earth’s surface is covered with water

BUT 97.5% of this water is salt water

FRESHWATER Only 2.5% of the planet’s water is freshwater,

and only 1% of that exists on Earth’s surface1%=lakes, rivers20%=groundwater79%=ice caps and glaciers

MATTER RECYCLING IN ECOSYSTEMS

Law of Conservation of Matter: matter is neither created nor destroyed. Just moved around and transformed.

Biogeochemical cycles: the movement of chemicals through the components of the Earth system.These components are also called

“biogeochemical reservoirs”.

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COMPONENTS OF THE EARTH SYSTEM

Lithosphere: the solid Earth; land


Lithosphere: the solid Earth; land Hydrosphere: the liquid Earth; water


Lithosphere: the solid Earth; land Hydrosphere: the liquid Earth; water Atmosphere: the gaseous Earth; air


Lithosphere: the solid Earth; land Hydrosphere: the liquid Earth; water Atmosphere: the gaseous Earth; air Biosphere: living things (organisms)and

the parts of the lithosphere, hydrosphere, and atmosphere in which things live


Lithosphere: the solid Earth; land Hydrosphere: the liquid Earth; water Atmosphere: the gaseous Earth; air Organisms: living things Cryosphere: frozen or solid water such

as ice caps, glaciers, snow and permafrost

HYDROLOGIC CYCLE

Hydrologic cycleCycling of water in and out of atmosphere

and between all the earth’s components. All of the water on our planet is recycled

and a given molecule of water is used over and over throughout time.

Water is the primary medium by which energy and matter move are circulated through the Earth system components.

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THE HYDROLOGIC CYCLE• Water enters the atmosphere by evaporation and by

transpiration from leaves.

• It condenses and falls from the atmosphere as precipitation.

• When water falls as precipitation on land, it has two possible pathways:

1. Returns to the hydrosphere by flowing as runoff from the land surface into streams, rivers, lakes, and eventually the ocean.

2. Returns to the lithosphere by infiltration into the ground becoming soil water or ground water.

Hail

Hail

HailHail

Hail

Hail

fog

fog

fogfog

fog

fog

Precipitation -

Any form of water that falls to Earth from the atmosphere

WATER APPEARS IN ALL 3 OF ITS PHASES AT DIFFERENT TIMES DURING THE HYDROLOGIC CYCLE

1. Solid• Ice, hail, snow, glaciers, ice caps etc.

2. Liquid• Water droplets, including clouds, lakes, streams

etc.

3. Gas• Water vapor

WATER VAPOR

O

H

H

+

+-

O H

H

+

+

-

O H

H

+

+-

O

HH

++

-

O

HH

++

-

O

H

H

+

+-

O

H

H

+

+-

OH

H

+

+

-O

H

H

+

+-

WATER CONDENSATION

O

H

H

+

+-

OH

H

+

+ -

O

HH

++

-

O

HH

++

-

O

HH

++

-

O

HH

++

-

O

H

H

+

+-

OH

H

+

+

-

O

H

H

+

+-

FIVE PROCESSES OF THE HYDROLOGIC CYCLE1. Precipitation: Any form of water falling from the

atmosphere to the ground.

2. Condensation: The process of changing from a gas to a liquid

3. Evapotranspiration: Evaporation: the transformation of water from liquid to gas

phases as it moves from the ground or bodies of water into the overlying atmosphere. The source of energy for evaporation is primarily solar

radiation

Transpiration: the release of water vapor from plants into the atmosphere. Evaporation + transpiration=evapotranspiration

INFILTRATION AND RUN-OFF4. Run-off: variety of ways water moves

across the land Snowmelt: run off from melting of snow

on mountain tops Water can flow to rivers, lakes,

reservoirs, oceans or infiltrate into soil5. Infiltration: flow of water from surface into

the groundOnce in ground can become soil water or

ground water

HYDROLOGIC CYCLE POWERED BY:

• Gravity(precipitation)

Solar Energy

(evaporation)

SO, WHERE DOES WATER GO WHEN IT FALLS ON EARTH?

about 76% lost to evaporation 32% run-off small percent infiltrates into

groundwater

LE 3-16

Atmosphere13,000

Evaporation425,000 71,000 Precipitation

111,000 Ice caps, glaciers,and snowfields

33,000,000

EvaporationTranspirationExtractionRivers

Precipitation385,000

Runoff40,000

Oceans1,350,000,000

Groundwater15,300,000

Extraction

Human use Uptake

Land plants

Soil water 122,000

Infiltration<11,000 Water

table

Aquifer

Food for thought…Where does the hydrological

cycle begin and end?

QUESTION: TESTING YOUR COMPREHENSION

Water enters the atmosphere through the process of…?

a. Precipitation

b. Transpiration

c. Infiltration

d. Runoff


Water enters the atmosphere through the process of…?

a. Precipitation

b. Evaporation

c. Infiltration

d. Runoff


Water enters the lithosphere through the process of…?

a. Precipitation

b. Transpiration

c. Infiltration

d. Runoff

PART III: HYDROLOGIC CYCLE

& CLIMATE

CLIMATE CONCEPTS: RISE OR SINK

Warm air risesOpen the oven, you feel the heat on

your face Cold air sinks

Open the freezer, you feel the cold at your feet

http://science.howstuffworks.com/hot-air-balloon.htm

Warmer Air

Cooler Air

Cooler Air

Warmer Air

Equal Air Temp

Equal Air Temp

Statically unstable

Statically neutral

Statically stable

CLIMATE CONCEPTS: RISE OR SINK

When air rises, it coolsTop of mountain is cooler than the base of the

mountain. When air sinks, it warms

The base of the mountain is warmer than the top of the mountain.

CLIMATE CONCEPTS: WARM OR COLD

Warm air holds more water Cold air holds less water

CLIMATE CONCEPTS: WATER IN AIR

As air rises, it cools Cooler air holds less water vapor. If it gets even cooler, then it rains RISING AIRRAIN


As air descends, it dries warmer air holds more water vapor. As air dries, it is less likely to rain DESCENDING AIRDRY


The temperature to which the air had to cool to become totally saturated is called:

Dew point: the temperature at which the relative humidity = 100%

DEW POINT

The temperature at which dew (condensation) begins to form

Dew is the water you find on your grass or car early in the morning.

Frost is when water is deposited as small ice crystals.

Frozen dew is liquid dew that freezes. If the temperature reaches the dew point

temperature, then dew (or frost) will form. http://apollo.lsc.vsc.edu/classes/idm3020/tut_folder/nick_tutorial/

CLIMATE CONCEPTS: REVIEW

Warm air holds (more or less?) water vapor; cold air holds (more or less?) water vapor.

As air cools down, the chance of rain increases or decreases?

As air rises, the chance of rain increases or decreases?

WHAT CAUSES PRECIPITATION?

Rain = moisture + cooled down air

No Rain = low moisture and/or heated up air

HYDROLOGIC CYCLE & CLIMATE

Solar radiation is most intense at the equator for two reasons:

1) the sun’s rays are concentrated in a smaller area 2) the sun moves through less atmosphere


Equator

30°N

30°S

60°N

60°S

90°N

90°S

Tropics arehot


Equator

30°N

30°S

60°N

60°S

90°N

90°S

Hot airrises


Air cools asit rises; sinks30°N and S

Equator

30°N

30°S

60°N

60°S

90°N

90°S


Each convectioncell is called aHadley Cell

Equator

30°N

30°S

60°N

60°S

90°N

90°S

http://uk.encarta.msn.com/media_461550429_781534817_-1_1/hadley_cells_and_the_itcz.html

Hadley cells


Descending air at30°N & S is warmand dry

Equator

30°N

30°S

60°N

60°S

90°N

90°S

30TH DEGREE LATITUDE DESERTS

30th degree N & S are areas of sinking air / areas of high pressure

HYDROLOGIC CYCLE & CLIMATE CHANGE Scientists have measured an intensification of

the hydrological cycle due to global warming: Globally, the average atmospheric water vapor

concentrations have increased. It is predicted that this will lead to increased

precipitation rates in some areas. The largest increases in precipitation are expected

to occur near polar regions, for two reasons. One, observations and climate models indicate that the

warming rate has been and will continue to be the highest there, and warmer air can hold more water vapor.

Two, the warming will reduce the extent of sea ice , thereby allowing more evaporation from open water.

Cycles of wet and dry periods are normal, however,

When the hydrological cycle is out of balance (or intensified due to climate change), these can lead to more extreme flooding and drought cycles

HYDROLOGIC CYCLE SUMMARY Cycling of water in and out of the atmosphere

and between all the earth’s components. Water evaporates from the surface of the earth, rises

and cools, condenses into rain or snow and falls again to the surface. The water falling on land collects in rivers and lakes, soil, and porous layers of rock, and much of it flows back into the ocean.

Plays an important role in determining climatic patterns plant growth heat energy transfer erosion rates rates of rock weathering

Hydrologic Cycle

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