Energy Relationships Energy Relationships and the Biosphere and the Biosphere

Section 2.1 Section 2.1

The Electromagnetic The Electromagnetic SpectrumSpectrum The sun emits electromagnetic radiation.The sun emits electromagnetic radiation. The electromagnetic spectrum shows us The electromagnetic spectrum shows us

all the different wavelengths within the all the different wavelengths within the sun’s radiation.sun’s radiation.

Insolation & Angle of Insolation & Angle of Inclination Inclination

InsInsoolation:lation: The The amount of solar energyamount of solar energy received by a received by a region of the Earth’s surface. region of the Earth’s surface.

Angle of InclinationAngle of Inclination: Refers to the : Refers to the degree of the earth’s degree of the earth’s tilt. 23.5tilt. 23.5°°

The The angle of inclination affects the insolationangle of inclination affects the insolation.. The angle points the northern hemisphere towards the The angle points the northern hemisphere towards the

sun in June.sun in June. The angle points the northern hemisphere away from the The angle points the northern hemisphere away from the

sun in December. sun in December.

Angle of Inclination & Angle of Inclination & the Seasonsthe Seasons

Latitude: Latitude: Imaginary Imaginary lines that run lines that run parallelparallel to to the equator.the equator.

North & South North & South polespoles are are at at 9090° latitude° latitude

EquatorEquator is at is at 0° latitude0° latitude The tilt of the Earth The tilt of the Earth

paired with the rotation paired with the rotation around the sun causes around the sun causes a variation in seasons.a variation in seasons.

Solstice & EquinoxSolstice & Equinox

Summer SolsticeWinter Solstice

Spring Equinox

Fall Equinox

Solstice & EquinoxSolstice & Equinox

Solstice:Solstice: One of two One of two point’s in the Earth’s point’s in the Earth’s orbit at which the orbit at which the poles are poles are most tilted most tilted towards or away from towards or away from the sun. the sun.

Equinox: Equinox: One of two One of two points in the Earth’s points in the Earth’s orbit when the orbit when the number of number of daylight daylight hours is equal to the hours is equal to the number of hours of number of hours of nightnight..

Solstice & EquinoxSolstice & Equinox

Summer SolsticeWinter Solstice

Spring Equinox

Fall Equinox

Insolation & Angle of Insolation & Angle of Incidence Incidence The The angle between a ray falling on angle between a ray falling on

the surface and the line the surface and the line perpendicularperpendicular to that surface. to that surface.

The angle of incidence determines The angle of incidence determines how much solar energy an area how much solar energy an area receives.receives.

Higher latitudes receive less solar Higher latitudes receive less solar energy than equatorial latitudes. energy than equatorial latitudes.

Insolation & Angle of Insolation & Angle of IncidenceIncidence

Almost perpendicular

Less perpendicular

Direct hit more light

Less light more spread out

Insolation & Angle of Insolation & Angle of IncidenceIncidence

Absorption Absorption

All four layers of the atmosphere absorbAll four layers of the atmosphere absorb incoming radiation from the sun.incoming radiation from the sun.

NN22 and O and O22 in the mesosphere, in the mesosphere, thermosphere and stratosphere absorb thermosphere and stratosphere absorb gamma and X-raysgamma and X-rays..

Ozone in the stratosphere absorbs UV Ozone in the stratosphere absorbs UV radiationradiation

COCO22, H, H22OO in the troposphere in the troposphere absorb absorb infrared (heat)infrared (heat)

Visible light + Radio Waves make it Visible light + Radio Waves make it through to the earth’s surface.through to the earth’s surface.

AlbedoAlbedo Reflected solar radiationReflected solar radiation.. Light shades and shiny surfaces reflectLight shades and shiny surfaces reflect

radiant energyradiant energy Dark shades and dull surfaces absorbDark shades and dull surfaces absorb radiant radiant

energyenergy Earth’s albedo is 30%Earth’s albedo is 30% (not spread evenly (not spread evenly

throughout the planet)throughout the planet)

AlbedoAlbedo

Net Radiation BudgetNet Radiation Budget

Not all incoming radiation is absorbedNot all incoming radiation is absorbed Some is re-emitted as thermal energySome is re-emitted as thermal energy The The net-radiation budgetnet-radiation budget is the is the

difference between the incoming difference between the incoming radiation and the outgoing radiationradiation and the outgoing radiation

Incoming radiation is all of the radiation Incoming radiation is all of the radiation that reaches the surface of the Earththat reaches the surface of the Earth

Outgoing radiation refers to that which Outgoing radiation refers to that which is emitted from the Earth’s surface and is emitted from the Earth’s surface and atmosphereatmosphere

Trends in Radiation Trends in Radiation

Incoming Radiation – Outgoing Radiation = Net Radiation Incoming Radiation – Outgoing Radiation = Net Radiation BudgetBudget

Poles – low insolation and high Poles – low insolation and high albedo results in a net radiation albedo results in a net radiation deficit.deficit.

Equator – High insolation and low Equator – High insolation and low albedo results in a net radiation albedo results in a net radiation surplus. surplus.

The Natural Greenhouse Effect

• Greenhouse gases (GHGs) in our atmosphere trap in heat radiated from earth.• GHGs: water vapour, carbon dioxide, nitrous oxides and methane.

• Without the greenhouse effect, earth would be covered completely with ice.

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