environmental sciences course earth sciences. the geochemical model solar radiation natural...

Environmental Sciences Course

Earth Sciences

The Geochemical Model Solar Radiation Natural Hazards Earthquakes Volcanic hazards Floods Tornados and storms Desertification

University Of PalestineEnvironmental Science I 2

University Of Palestine Environmental Science I 3

The Geochemical

Model


Lithosphere:

- the solid outermost shell of a rocky planet.- includes the crust and the uppermost

mantle- Composed of fractured rocks;- Is underlain by asthenosphere,- Thickness 100-120km;- Compse Continents, ocean bottoms and

mountains- Earthquakes and volcanoes

The Geochemical Model


Pedosphere

- The outermost layer of the Earth that is composed of soil and subject to soil formation processes

- Located above the lithosphere,

- Very important for plants; Rich of organic materials; Include air and water;

- Type of soil depend on the rock origin, weather and climate, topography, etc.



Hydrosphere

•describes the collective mass of water found on, under, and over the surface of a planet.•(oceans, seas, rivers, lakes, iceglacies, Groundwater)•Water depth in rivers and lakes not exceeds tenths of meters where it reaches kilometers in seas and oceans.•Water covers about 71% of earth concentrated in the southern half of Earth;



Biosphere

Includes life classes in water, lithosphere, pedosphere and air;

Life classes about 4.5 million type, most of them depends on photosynthesis process which depends on sunshine;

99% of the biosphere is composed of oxygen, hydrogen, carbon and nitrogen.


Atmosphere- Starts from some meters below the earth

surface to reach hundreds of kilometres above the surface;

- Composed of 78% Nitrogen, 21% oxygen, 0.9% Argon, 0,03% Carbon dioxide, and Neon and Helium gases;

- Divided in many stratas and the most important one is troposphere;

- Most of air mass is concentrated in troposphere;




Atmosphere (Radiation)

- The Sun radiates in all directions and the Earth, being a very small target at a distance of 150 million km, intercepts 0.0005 % of the total.

-At the top of the Earth’s atmosphere this amounts to about 1360 W m-2 , a value known as the ‘solar constant’.

The solar constant is the amount of incoming solar electromagnetic radiation per unit area


- Solar output is not as constant as this name suggests. Between 1981 and 1984, it decreased by 0.07 %


0.1 % sustained over a decade would be sufficient to produce major climatic effects

5 % decrease might trigger a major glaciations


- Cyclical variations in the Earth’s rotation and orbit also alter the solar constant

- Rather less than half of the solar radiation reaching the top of the atmosphere penetrates all the way to the surface.

- most of the ‘lost’ incoming radiation is reflected directly back into space, and about 10 per cent is absorbed or scattered by ozone, water vapor, and particulate matter in the troposphere (the sky its color) .

Solar Radiation


Solar Radiation

The proportion of light reflected by a surface is called the ‘reflection coefficient’, or more usually ‘albedo’ of that surface. It can be measured and is usually expressed as a fraction or a percentage, albedo varies widely from one surface to another.

1- Earthquakes2- Volcanic hazards3- Floods4- Tornados and storms5- Desertification


Natural environmental hazards


Faults

Is a planner rock fracture which shows evidence of relative movement

Types of Faults• Normal fault• Thrust fault• Lateral slip


Earthquakes

• An earthquake is the result of sudden release of stored energy in earth’s crust that create seismic waves

• The movement of Earthquake waves through the Earth’s interior has given us a better picture of the earth’s interior.


Earthquakes


P-waves are faster than S-waves. The density and elasticity of rock affects the speed of the waves.

When p-waves hit the core, they are refracted and slow down. This creates a P-wave shadow 103º -143 º from the focus

Earthquakes

S-waves can’t travel through liquids.

When S-waves hit the outer liquid core, they stop. This creates a S-wave shadow at locations greater than 103º from the focus of the earthquake.


Earthquakes


Earthquakes have even shown the depth of the crust.

A sharp boundary between the crust and the upper mantle at about a depth of 30km exists. P-waves travel at 6.75 km/sec in the crust and 8 km/sec below this boundary. The depth of this boundary varies depending if it is under continents (20 - 90 km) or under ocean floors (5 to 10 km).

The speed of seismic waves increases with depth in the mantle except for a low velocity zone at 100-250 km, this corresponds to the asthenosphere.

Earthquakes

The strength of an Earthquake can be measured in two different ways

Intensity: is a qualitative assessment of the kinds of damage done by an earthquake it is subjective (Modified Mercalli Intensity scale ( I to XII)

Magnitude: is a quantitative measurement of the amount of energy released by an earthquake Richter Magnitude scale (open-ended scale) each step in the richter scale is:

increase 10-fold in movement 30-fold increase in energy



Earthquake Damage depends on many factors:

-The size of the Earthquake

-The distance from the focus of the earthquake

-The types and properties of the materials at the site

-The nature of the building

Earthquakes


-About 80% of earth’s surface, the seafloor as well as the land, began as molten rock that rose from deep inside the earth. When it emerged onto the surface, it cooled and hardened into volcanic rock.

-Volcanisms occur principally near plate boundaries. -Can be beneficial as sources of fertile soil, chemicals, and

minerals -Can be troublesome-the dust and gas thrown high into the

atmosphere in a severe eruption can partial block out solar radiation etc.

-Destroying cities and even bringing civilization to an end.

Volcanisms

1. CausesHeavy rainfallCoastal flooding due to sea stormsDam failures2. EffectsPrimary (death, destroy buildings etc.) Secondary and tertiary (diseases, electricity and water

cuts, etc.)


Floodings

1.Tornados Most tornadoes have wind speeds of (177 km/h) or

less, are approximately (75 m) across, and travel a few kilometers before dissipating.

Some attain (wind speed >450km/hr) (1.6 km across)

Due to collision between cold air mass and warm-humid air mass.

Very low central pressure It is characterized by local effects and short duration Famous in middle and southeast USA.


Tornados and storms

2.Typhoons and hurricanesCircular with diameter reach 600 km;Duration many weeks;Wind speed >300 km/hr;When it reaches the coast it forms very high and

strong waves reaches 7 m height.3. TsunamiVery strong waves becomes with earthquakes and

volcanoes.


Tornados and storms

environmental sciences course earth sciences. the geochemical model solar radiation natural...

Documents

solar constant

earth surface

solar output

water type

collective mass of water

air mass

atmosphere radiation0

earths atmosphere