Hydrospherehttp://www.3plains.com/u

Hydrosphere
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Hydrosphere
 The Hydrologic Cycle
 Ocean
 Ocean Currents
 Tides3
The Hydrologic Cycle4
The Water Cycle:
The Hydrologic Cycle:
 Describes the constant circulation of water among
the sea, land, the biosphere, and the atmosphere.
 About 1.3 billion cubic km(m3
) of water exist at the
Earth’ surface.
 97.5% is salty seawater
 1.8% is frozen into the great ice caps of Antarctica and
Greenland.
 Only0.64% is fresh and available in streams, ground water,
lakes, and wetlands. 5
The Hydrologic Cycle :
Earth as a System:
 The circulation of Earth' water supply is
called the hydrologic cycle
The Hydrologic Cycle :
 Water can readily change from one state of
matter (solid, liquid, or gas) to another at the
temperatures and pressures occurring at
Earth’ surface.
 Therefore water is constantly moving among
the oceans, the atmosphere, the solid earth,
and the biosphere.8
 Water evaporates into the atmosphere from
the ocean and to a much lesser extent from
the continents.
 Winds transport this moisture laden air, often
great distances, until conditions cause the
moisture to condense into clouds, and
precipitation that falls into the ocean has
completed its cycle and is ready to begin
another.
The Hydrologic Cycle : 9
The Hydrologic Cycle :
 The precipitation that falls on the continents
follows four different paths
1. Surface water flowing to the sea in steams and
rivers is called runoff. Finally it flows to the
oceans.
2. Some water seeps into the ground know as
ground water. 60 times more water is ground
water than in all streams, lakes, and wetlands
combined.10
The Hydrologic Cycle :
3. The water soaks into the ground (called
infiltration) and slowly moving downward. Finally
into the ocean. Most of the remainder of water that
falls onto land evaporates back into the
atmosphere.
 When some of water that infiltrates the ground
surface is absorbed by plants, which then release
it into the atmosphere, this process is called
transpiration.11
The Hydrologic Cycle :
4. A small amount of water is also
incorporated into tissue when plants grow.12
Ocean13
Ocean :
 Earth is a planet dominated by oceans.
 71% of Earth’s area consists of oceans and
marginal seas.
 The three major oceans.
 Pacific the largest
 Atlantic
 Indian14
The oceans of the world
 The “Seven seas”
1. The North Atlantic
2. South Atlantic
3. North Pacific
4. South Pacific
5. Indian
6. Arctic
7. Antarctic Show map15
The oceans of the world
Ocean :
 The pacific contains slightly more than half of
the water in the world ocean. And has the
greatest average depth 3940 meters.
 Salinity is the proportion of dissolved salts to
pure water. Usually expressed in parts per
thousand(%o).
 The average salinity in the open ocean
ranges from 35 %o to 37 %o17
Ocean :
 The principal elements that contribute to the
ocean’s salinity are chlorine (55%) and
sodium (31%)
 The primary sources of the elements in sea
salt in the ocean are chemical weathering of
rocks on the continents and volcanic
outgassing.
 Outgassing is also considered to be the
principal source of water in the oceans as
well as in the atmosphere.18
The Ocean’s Layered Structure
 Temperature and salinity vary with depth.
 Oceanographers divided the open ocean
into three-layered structure.
1. A shallow surface mixed zone.
2. A transition zone.
3. A deep zone.
 According to the solar energy that the ocean
surface received.19
A Shallow Surface Mixed Zone (2%)
 The thickness and temperature of this layer
vary, depending on latitude and season.
 The zone may attain a thickness of 450 m or
more, and temperatures typically range
between 20C and 26 C
 In equatorial latitudes, the temperatures may
be even higher.20
A Transition Zone (18%)
 This layer of rapid
temperature change,
know as the
thermocline.
 Marks the transition
between the warm
surface layer and the
deep zone of cold water
below.
 Below the thermocline
temperatures fall only a
few more degrees.
http://oceanservice.noaa.gov/education/yos/resource/JetStream/ocean/images/thermocline.jpg
Thermocline
Temperature Profile21
Deep Zone (80%)
 At depths greater than about 1500 meters.
 Ocean-water temperatures are consistently
below 4C
 Ocean depths are determined using echo
sounders and multibeam sonars.22
Salinity Variations
 Correspond to the depth of general three-layered
system described for temperatures.
 In the low and middle latitudes, a surface zone of
higher salinity is created when freshwater is
removed by evaporation.
 Below the surface zone, salinity decreases rapidly.
This layer of rapid change in salinity is called
holocline, corresponds closely to the thermocline.
 Below the halocline salinity variations are small.23
Ocean Currents
Ocean Current
 Two types of Ocean Current
1. Surface Currents
2. Deep Ocean Circulation25
Surface Currents
Ocean Circulation Patterns
 Produced by persistent wind patterns.
 Transport of large amounts of energy from
tropical latitudes to polar regions.
 Great degree of interaction that occurs
between the hydrosphere and the
atmosphere.
 Global winds help to create ocean currents.26
Surface Currents
Ocean Circulation Patterns
 Ocean currents act to modify climates worldwide.
 The Coriolis effect, a force created by Earth’s
rotation, influences ocean currents and global
winds.
 Currents are deflected to the right in the Northern
Hemisphere and to the left in the Southern
Hemisphere by the Coriolis effect.27
Deep Ocean Circulation
 Driven by density differences and by gravity rather
than by winds.
 Temperature and salinity combine to affect the
density of water.
“4 C is denser”
 More salts in the ocean water also rise the density.
 Cold and very saline, dense water sink and travel
toward the Equator at great depths.28
Deep Ocean Circulation
http://www.scholarsandrogues.com/wp-content/uploads/2009/01/deepcurrents.jpg29
Surface and Deep-Water Currents of the
Atlantic Ocean
1. Warm surface waters from equatorial regions flow
into the North Atlantic.
2. They cool, become saltier, and sink.
3. Cool salty water flows along the seafloor toward
the equator.
4. Some seep water flow south where they rise along
the Antarctic cost.
 Surface and deep-water currents combine to affect
climate and other components of Earth Systems.30
Tides31
Tides
 The ocean rises and falls on a cyclical basis.
 Caused by the gravitational attraction of the
Moon and, to a lesser extent, by the Sun.
 Most coastlines experience two high tides
and two low tides during and interval of about
24 hours and 53 min.32
Tides
 If the ocean level reach the maximum height
at about 6:13 P.M., it will be low again at
about 12:26 A.M.
 Two type of tides
 Spring tides: larger
 Neap tides: smaller33
Spring Tides
 Near the times of new and full moons, the
Sun and Moon are aligned and their
gravitational forces are added together to
produce especially high and low tides, these
are called the spring tides
 The variation between high and low tides is
large.34
Spring Tides
Neap Tides
 Conversely, at about the times of the first and
third quarters of the Moon, when the
gravitational forces of the Moon and Sun are
at right angles, the daily tidal range is less,
this are called reap tides.
 The differences between the levels of height
and low tide are smaller.36
Neap Tides
http://oceanservice.noaa.gov/education/yos/resource/JetStream/ocean/tides.htm37
The End