the sun - driving force for climate

Climate and Global Change Notes

10-1

The Sun - Driving Force for Climate

Str

atos

pher

ic

Che

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try/

Dyn

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s OceanDynamics

TerrestrialEnergy/Moisture

Global Moisture

Marine/Biogeochemistry

Ext

erna

l For

cing

CO2

Sun

Vol

cano

es

Soil

ClimateChangeAtmospheric Physics/Dynamics

LandUse

CO2

Pollu-tants

Tropospheric Chemistry

HumanActivities

TerrestrialEcosystems

Biogeochemical Systems

Physical Climate Systems

Hum

an Forcing


10-2


Solar Radiation and Its Variability

The SunSolar Radiation Source

Solar System

Solar Radiation VariabilitySolar Output VariationsPlanet-to-Planet VariationsLatitudinal Variations

Seasonal Variations

Long-Term VariationsMilankovitch Cycles

Science Concepts

Nuclear Fusion ProcessEinstein’s E = m c2 Law

Sun Spots1/R2 LawIntensity

Angle of IncidenceSpherical Shape of Earth

Axis of RotationOrbital Plane

EccentricityPrecessionObliquity

The Earth System (Kump, Kastin & Crane)

• Chap. 1 (pp. 14-15) • Chap. 4 (pp. 58-59; 66-68)• Chap. 15 (p. 303-306) • Chap. 14 (pp. 274-278)


10-3


The Sun

• Introduction

Science quotes of 5th and 6th graders -

Most books now say our Sun is a star. But it still knows how to change back into a Sun in the daytime.

QuickTime™ and aCinepak decompressor

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10-4


The Sun (Con’t)

• Medium size star- Diameter = 1.39 x 10 6 km

(109 times the diameter of Earth)- Mass = 2.0 x 10 30 kg

(3.3 x 10 5 times the mass of Earth)

• Rotation period = average ~27 days- Variable rotation; Equatorial regions (~25 days)

faster than polar regions (~35 days)

Extremeuv (30.4 nm)

Image

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10-5


The Sun (Con’t)

• Average temperature star

- Interior temperature 15 x 10 6 K- Exterior skin temperature 6000 K

• Interior pressure = 100 x 10 9 times the surface pressure of the Earth

http://sohowww.nascom.nasa.gov/

http://sohowww.nascom.nasa.gov/

X-Ray Image

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Coronal Mass Ejection over 8-h period 5-6 August 1999

171 10-10 m emission

showing the solar corona at a temperature

of about 1.3 million K



QuickTime™ and aMicrosoft Video 1 decompressorare needed to see this picture.


10-6


The Sun (Con’t)

• Plot of the relative number of stars vsabsolute magnitude shows that fainter stars (large magnitudes) are much more numerous than brighter stars

• The Sun is more luminous than the majority of stars

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10-7


Solar Radiation

• Energy Source

- Nuclear “fusion” of hydrogen to make helium, i.e., H2 + H2 => He4

• Energy Amount

- Converts 657 x 106 tons of H2 per s (596 x 109 kg / s)

- Produces 653 x 106 tons of He2 per s (592 x 109 kg / s)

- Thus, about 4 x 109 kg / s of mass is converted to energy

- Using Einstein's formula, E = m c2 where E is Energy; m is Mass; c is Speed of light,3 x 108 m / s. Dividing by time, t, yields P = E / t = ( m c2 ) / t where P is Power

- Substituting the values for the Sun yields about P = 3.6 x 1026 watts> Note a watt equals a cal / s


When they broke open molecules, they found they were only stuffed with atoms. But when they broke open atoms, they found them stuffed with explosions.

This is fission.


10-8

Solar Radiation Variability

http://spaceweather.com/2/25/04

Solar Output Variability

• Sunspots appear as dark spots where temperatures in thecenters drop to about 3,700 K

• Sunspots typically last several days; very large ones may last for several weeks

• Sunspots are magnetic regions with magnetic field strengths thousands of times stronger than the Earth's magnetic field

• Sunspots usually come in groups

• Not many sunspots at this time, but sometimes monthly average is over a hundredhttp://science.msfc.nasa.gov/ssl/pad/solar/feature1.htm#Sunspots


10-9


http://earthobservatory.nasa.gov/Study/VariableSun/

Solar Output Variability (Con’t)

• Sunspot number

• Note 11 year solar or sunspot cycle

• Amount of energy emitted by the Sun isrelated to the sunspot cycle


10-10


http://www.doc.mmu.ac.uk/aric/gccsg/2-5-3.html

Solar Output Variability (Con’t)

• Variations in solar irradiance at the top of the Earth’s atmosphere over the last 120 years

- Note 11-year solaror sunspot cycle

- Very slight increase over this 100+ record

Bulletin of American Meteorological Society, June 2003, p. 743


10-11

The Solar System

Percentage Mass of Components

• Sun: 99.85%

• Planets: 0.135%

• Comets: 0.01% ?

• Satellites: 0.00005%

• Minor Planets: 0.0000002% ?

• Meteoroids: 0.0000001% ?

• Interplanetary Medium: 0.0000001% ?

• Jupiter consists of more than twice the matter of all the other planets combined

To be a planet, an object must meet three criteria:

(1) It must have enough mass and gravity to gather itself into a ball.

(2) It must orbit the sun.

(3) It must reign supreme in its own orbit, having "cleared the neighborhood" of other competing bodies.


10-12

The Solar System

Description

• Sun and 8 planetsand dwarfplanets(Pluto and others)

• Satellites of the planets, numerous comets, asteroids, meteoroids, and the interplanetary medium

Sun

Mercury Earth

MarsVenus

Jupiter Saturn Uranus NeptunePluto & otherdwarf planets

http://photojournal.jpl.nasa.gov/


10-13

The Solar System

10th Planet Discovered??

• 29 July 29 2005 - Astronomers discovered a new planet beyond Pluto, about 97 times farther from the Sun than Earth, i.e., 97 Astronomical Units (AU).

• Scientists working to better estimate its size and its motions. They believe it is bigger than Pluto

• Astronomers determine a planets size by measuring its brightness

- Planets shine by reflecting sunlight- The bigger the planet, generally speaking, the more reflection

• The planet's temporary name is 2003 UB313. A permanent name has been proposed to the International Astronomical Union

http://science.nasa.gov/headlines/y2005/29jul_planetx.htm?list159742




10-14

The Solar System

10th Planet Discovered?? (Con’t)

• August 2006 - International Astronomical Union (IAU) General Assembly in Prague, stated that to be a planet an object must meet three criteria:

- it must have enough mass and gravity to gather itself into a ball.

- it must orbit the sun.

- it must reign supreme in its own orbit, having "cleared the neighborhood" of other competing bodies.

• Thus, Pluto and 2003 UB313 and several other objects circling the Sun in orbits similar to Pluto’s were defined as "dwarf planets”


10-15

The Solar System

Planet Plus Pluto Statistical Information

Dist = Distance to the Sun in AUs Radius = Radius in terms of the Earth’sMass = Mass in terms of the Earth’s Rotate = Rotation rate in Earth daysSat = Number of associated satellites Incl = Orbital inclination in degreesEccen = Orbital eccentricity Den = Density in g/m3

* Sun’s period of rotation at the surface varies from ~25 days at the equator to 36 days at the poles. Deep down, below the convective zone, the period of rotation appears to be 27 days.

Name Dist Radius Mass Rot Sat Incl Eccen Den

Sun 0. 109. 332800. 25.-36.* 9. -.- -.- 1.41

Mercury 0.39 0.38 0.05 58.8 0. 7. 0.2056 5.43

Venus 0.72 0.95 0.89 244. 0. 3.394 0.0068 5.25

Earth 1.0 1.00 1.00 1.000 1. 0.000 0.0167 5.52

Mars 1.5 0.53 0.11 1.029 2. 1.850 0.0934 3.95

Jupiter 5.2 11. 318. 0.411 16. 1.308 0.0483 1.33

Saturn 9.5 9. 95. 0.428 18. 2.488 0.0560 0.69

Uranus 19.2 4. 15. 0.748 15. 0.774 0.0461 1.29

Neptune 30.1 4. 17. 0.802 8. 1.774 0.0097 1.64

Pluto 39.5 0.18 0.002 0.267 1. 17.15 0.2482 2.03


10-16


Solar Radiation Intensity

• Intensity = energy per unit time per unit area = power per unit area; power

- Units> cal / s - m2 or watt / m2

‡ watt = cal / s

Solar Energy the Earth Receives

• Sun’s energy is emitted in all directions

• Intensity of the Sun’s energy decreases as the square of the distance from the Sun (radius of planet’s orbit) increases, i.e., referred to as the “One Over R 2

Law”I 1 / (distance ) 2 or I 1 / R 2


10-17


Solar Energy the Earth Receives (Con’t)

• The Earth intercepts only a small portion of the Sun’s energy; about 1.62 x 10 17 watts

• Solar power the Earth receives adds up to 18,000 times more energy than humankind consumes as fuel and commercial energy


10-18


Solar Energy the Planets ReceiveEnergy Received*

Name Dist (m) Radius (m) (watts)Mercury 5.85 X 10 10 2.42 X 10 6 1.54 X 10 17

Venus 1.08 X 10 11 6.05 X 10 6 2.83 X 10 17

Earth 1.50 X 10 11 6.37 X 10 6 1.62 X 10 17

Mars 2.25 X 10 11 3.38 X 10 6 2.03 X 10 16

Jupiter 7.80 X 10 11 7.01 X 10 7 7.26 X 10 17

Saturn 1.43 X 10 12 5.73 X 10 7 1.46 X 10 17

Uranus 2.88 X 10 12 2.55 X 10 7 7.04 X 10 15

Neptune 4.52 X 10 12 2.55 X 10 7 2.87 X 10 15

Pluto 5.93 X 10 12 1.15 X 10 6 3.37 X 10 15

Dist = Distance to the SunRadius = Planet’s radiusEnergy Received = Energy received from the Sun

• Calculations based on numbers from the class laboratory exercise. More precise numbers will yield slightly different results.

Sun

Mercury Earth

MarsVenus

Jupiter Saturn Uranus Neptune Pluto


10-19


Radiation Balance Assumption

Temp withName Temp (K) Albedo (K)Mercury 438.Venus 322. 228. (75%)Earth 274. 250. (30%)Mars 223. 215. (15%)Jupiter 120.Saturn 89.Uranus 62.Neptune 50.Pluto 44.

Temp = Planet’s average temperature assuming planet is a solid globe with no atmosphere and no albedo

Temp with Albedo = Planet’s average temperature assuming planet is a solid globe with no atmosphere, but with an albedo

IncomingSolar

Radiation

OutgoingRadiation

Solid Planet


10-20

Solar Angle and Intensity• Area of a flashlight beam spreads over a larger area as the flashlight moves

from directly overhead to a more glancing angle• Intensity decreases as the angle between the light’s rays and the surface

decreases

Directly Overhead Glancing Angle

Side View

Overhead View



10-21


Solar Angle and Intensity (Con’t)

• Global variability

- Tilt of axis effect onsolar intensity

http://svs.gsfc.nasa.gov/vis/a000000/a000000/a000077/index.html

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10-22


• Intensity decreases as the angle between the Sun's rays and the Earth's surface decreases

> Angleincreasesas moveaway fromtropics




Glancing Angle

Directly Overhead

Axis of Rotation


10-23



Axis of Rotation

Atmospheric Layer

PenetrationDepth

PenetrationDepth


• Intensitydecreases as the depth of atmosphere penetrated increases


SolarRays

SolarRays


10-24



• Global variability

- Spherical shape of the Earth

• Local variability

- Mountains

> Southside for wine in NY

> North side for ski slopes in NY

400

300

200

100

0 10N 10S 30S 30N 50S 50N 90S 90N

Latitude

Solar Radiation Intensity Received

Rad

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In

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( W

/ m

2 )


10-25


Earth’s Orbit

• Note: Orbit is elliptical;it has an eccentricity

aaa

September 23SunMarch 21

June 22December 22AphelionAboutJuly 4PerihelionAboutJanuary 3147 x 106 km

152 x 106 km


10-26


Seasons • Caused by the tilt of the Earth's axis with

respect to the plane of the Earth's orbit

- Changes both the angle between the Sun's rays and the Earth's surface and the depth of atmospheric penetration

- Changes the length of daylight

- Example: December solstice (Northern Hemisphere Winter solstice)

Factoids -

A planet’s rotation and tilt are result of collisions.

Uranus axis is tilted 90°.

Venus rotates east to west instead of west to east like the Earth.


10-27


Seasons (Con’t)

• Earth’s annual trip around the Sun

http://svs.gsfc.nasa.gov/vis/a000000/a000000/a000077/index.html




10-28


Seasons (Con’t)

• Satellite view looking down on the North Pole


10-29


Seasons (Con’t)

• Satellite view looking up at the South Pole


10-30


Universal Timed h d h m d h m

2006Perihelion Jan 4 15 Equinoxes Mar 20 18 26 Sep 23 04 03 Aphelion Jul 3 23 Solstices Jun 21 12 26 Dec 22 00 22


2008Perihelion Jan 3 00 Equinoxes Mar 20 5 48 Sep 22 15 44Aphelion Jul 4 08 Solstices Jun 20 23 59 Dec 21 12 04


2010 Perihelion Jan 3 00 Equinoxes Mar 20 17 32 Sep 23 03 09Aphelion Jul 6 11 Solstices Jun 21 11 28 Dec 21 23 38

2011Perihelion Jan 3 19 Equinoxes Mar 20 23 21 Sep 23 09 04Aphelion Jul 4 15 Solstices Jun 21 17 16 Dec 22 05 30

http://aa.usno.navy.mil/data/docs/EarthSeasons.html


10-31


Seasons (Con’t)• View of Earth from the Sun throughout the year

• North and South poles are denoted by

December SolsticeDecember 21-22

Sun Verticalat Latitude 23.5°S

March EquinoxMarch 21-22Sun Verticalat Latitude 0°

June Solstice June 21-22Sun Vertical

at Latitude 23.5°N

September EquinoxSeptember 21-22

Sun Verticalat Latitude 0°


10-32


Seasons (Con’t)• Earth year animation from the Sun’s point of view


10-33

Global Radiation Budget Variations

Seasons (Con’t)

Summer - 6/21 23:00 UTC From 0° Winter - 12/21 23:00 UTC

http://www.fourmilab.ch/cgi-bin/Earth

Circle of illumination

Sun’s Rays


10-34


Seasons (Con’t)

Summer - 6/21 23:00 UTC From 45°S Winter - 12/21 23:00 UTC

http://www.fourmilab.ch/cgi-bin/Earth

Arctic Circle


10-35


Special Latitudes

• Based on the Sun’s angle with the Earth’s surface

23.5°N66.5°N66.5°S23.5°S0°Arctic CircleTropic of CancerEquatorTropic of CapricornAntarctic CircleAxis of Rotation23.5°NP


10-36


Seasons (Con’t)• Antarctic Daylight




10-37

Solstice Shadows at Local Noon June 21, '02 Dec. 22, '02 Shaq's (7’ 1”) Shadow

Where Length of shadow Length of shadow Max - Min (ft, in) Your height Your height

North Pole (90°N) 2.3 no shadow 16' 4"Los Angeles (34°N) 0.19 1.6 1' 4” - 11' 4Huntsville (34°N) 0.19 1.6 1' 4” - 11' 4New York (41°N) 0.31 2.1 2' 2” - 14' 11"Buenos Aires (34°S) 1.6 0.19 1' 4” - 11' 4"Johannesburg (26°S) 1.2 0.05 0' 4” - 8' 5”South Pole (90°S) no shadow 2.3 16' 4"

The ratio of your height and the length of your shadow at local noon on Jun 21st and Dec 22nd. To calculate how long your shadow would be on the first day of summer in N.Y., multiply your height by 0.31 -- the ratio listed for N.Y. on Jun 21.

Length of shadow = Your height * tan (90° - Sun elevation @ local noon)Sun elevation @ local noon = 90° - (Location’s latitude ± 23.5°)

where you use - if Sun is in your hemisphere and + if sun in alternate hemisphere



10-38


Seasons (Con’t)

Solar Parameters for: Huntsville, AL Philadelphia, PA(Latitude: 34.4°N) (Latitude: 40.0°N)

• June Solstice (Northern Hemisphere Summer)- Maximum solar altitude angle: 79.1° 73.5°- Longest day: 14.5 hours 15 hours- Shortest night: 9.5 hours 9 hours

• September Equinox (Northern Hemisphere Fall)- Solar altitude angle: 55.6° 50.0°- Day: 12 hours 12 hours- Night: 12 hours 12 hours

• December Solstice (Northern Hemisphere Winter)- Minimum solar altitude angle: 32.1° 26.5°- Shortest day: 9.5 hours 9 hours- Longest night: 14.5 hours 15 hours

• March Equinox (Northern Hemisphere Spring)- Solar altitude angle: 55.6° 50.0°- Day: 12 hours 12 hours- Night: 12 hours 12 hours


10-39


Seasons (Con’t)

All's Right With The Worldby Robert Browning (1812 - 1889)

The years at the springThe day's at the mornMorning's at sevenThe hill-side's dew-pearledThe lark's on the wingThe snail's on the throneGod's in his heaven...All's right with the world!

Great poem but does the science seem correct?


10-40




Seasons (Con’t)

• Insolation

- Incoming solar radiation- Solar energy per unit area

at the Earth’s surface

• Same as solar energy intensity

• Annual variation

• Note: Southern Hemisphere receives more radiation during its summer (January) than does the Northern Hemisphere during its summer (July)

- Remember Earth is closer to the Sun in July than January


South America has cold summers and hot

winters, but somehow they still manage.


10-41

Milankovitch Cycles

Earth’s Orbit

• Orbit changes with time in three ways

Eccentricity

• Defined as e = (a2 - b2)1/2 / a where a is the semi-major axisand b is the semi-minor axis

• Currently e = 0.0167

a

b

SunEarth

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Milankovitch(Serbian astronomer)

1943http://www.ngdc.noaa.gov/paleo/slides/images/base/iceage11.gif

http://earthobservatory.nasa.gov/Library/Giants/Milankovitch/

milankovitch.html

http://earthobservatory.nasa.gov/Library/Giants/Milankovitch/milankovitch_2.html


10-42

Milankovitch Cycles

Eccentricity (Con’t)

• Jupiter’s gravitational force results in Earth’s orbit varying from nearly circular with eccentricity near 0.0 to about 0.06

• Current difference in distance to the Sun at perihelion and aphelion is 3-4%

• Period - Dominate period of 413,000 and minor period of 100,000 years

http://www.museum.state.il.us/exhibits/ice_ages/eccentricity_graph.html

Eccentricity of the Earth's orbit over the last 750,000 years

Blue line traces the eccentricity of the elliptical orbit as it varies from circular (0.0); red line shows today's value for comparison.

Berger and Loutre (1991)

413,000 years 100,000 years


10-43

Milankovitch Cycles

Obliquity

• Change in the tilt of the Earth's axis

• Period — 41,000 years

• Changes between ~22.1° and ~24.5°

- Moon helps stabilize the obliquity;without the Moon this variation in the tilt could range much larger. The obliquity angle could reach 85°

• Less tilt implies

- More snow at poles because more moisture

- Cooler summers, thus less snow melt

- Therefore, good conditions for initiation of glaciers

23.5°

Orbital PlaneSun

Current tilt of axis is 23.5° buttilt varies from 22.1° to 24.5°



10-44

Milankovitch Cycles

Obliquity

• Variation in the tilt of the Earth's axis over the last 750,000 years

http://www.museum.state.il.us/exhibits/ice_ages/tilt_graph.html

Blue line traces the tilt in degrees; red line shows today's value for comparison



10-45

Milankovitch Cycles

Obliquity (Con’t)

• Change in Ice for past 21,000 years (1/2 period)

• Matches change in obliquity from 22.1° to 23.5°

http://geochange.er.usgs.gov/pub/sea_level/Core/raw/

quaternary/

images/gif/ice_age.gif


10-46

Milankovitch Cycles

Precession

• Wobble in the tilt of the Earth's axis

• Period — 22,000 years

• Like spinning top

• Changes hemispheric climate not whole Earth

Planetary axes would not precess or change obliquity if the planets were perfect spheres. However planetary rotation causes the equators to bulge. This gives a “handle” that the gravity of the other planets “grabs onto”, and twists the planetary spin. This causes precession and obliquity changes.


QuickTime™ and aSorenson Video 3 decompressorare needed to see this picture.


10-47

Milankovitch Cycles

Precession (Con’t)

• Precession of the equinox over the last 750,000 years

http://www.museum.state.il.us/exhibits/ice_ages/precession_graph.html

Blue line traces the precession; red line shows today's value



10-48

Milankovitch Cycles


• Current

• 11,000 years from now

SunDecember

September

June

March

SunDecember

September

June

March


10-49

Milankovitch Cycles


• Stars that Earth’s axis of rotationpoint as the axis precesses

• Note this means the pole starchanges with time

• Currently Earth’s axis points toward “Polaris”

Past, Present & Future Pole Stars

Year Constellation Closest Starc. 3,000BC Draco Thubanc. 1,000BC Usra Minor KochabPresent Usra Minor Polarisc. 4,000AD Cassiopeia Alraic. 7,500AD Cepheus Aldera minc. 14,000AD Lyra Vega http://inkido.indiana.edu/a100/celestialsphere2.html


10-50

Milankovitch Cycles


• Dating the Pyramids

- Egyptian pyramids at Giza were built roughly 4,500 years ago. How do we know?> By determining how long each individual

Pharaoh held power, adding all the years and working backwards ‡ Not very accurate

> Carbon dating ‡ Provides dates for the pyramids plus or minus 100 years

> Astronomical dating

The Ancient Egyptians aligned the sides of their pyramids to the points of the compass, with extraordinary accuracy. The most accurate is the Pyramid of Khufu, called the Great Pyramid. The east and west sides miss True North by less than three minutes of arc (roughly one tenth the diameter of the full moon). It took over 4,000 years before the astronomer, Tycho Brahe, was able to take astronomical measurements to a greater accuracy.

http://www.ukexpert.co.uk/photopost/data/588/7the-pyramids.jpg


10-51

Milankovitch Cycles


• How did they manage to align the sides so accurately with the North Pole?

Look at the time lapse photograph of stars over a full night. Note all the visible stars appear to move in circles (some big and some small). Today the star Polaris (The North Star or Pole Star) makes a very small circle indicating that it’s very near the Celestial North Pole.

Because of precession, the Earth’s axis of rotation is slowly sweeping out a great circle, pointing to different parts of the sky. In the years when the pyramids were being built, two stars, Mizar (Eta-Ursae Majoris) in the Big Dipper and Kochab (Beta-Ursae Minoris) in the Little Dipper, appeared to rotate around the Celestial North Pole.



Star trails as the United Kingdom Infrared Telescope (UKIRT) watches the night sky. CREDIT: Nik Szymanek. http://outreach.jach.hawaii.edu/pressroom/2003-estar/ukirtnight-small.jpg


10-52

Milankovitch Cycles


Precession is actually an advantage for dating thepyramids. If you use the method outlined to the right before 2,467 BC, your line would be slightly to the west of True North and after that date you'd be to the east of True North. The Pyramids of Giza show exactly this relationship - the earlier ones are aligned slightly to the west, and the later ones slightly to the east.

Using this method, dates of when the pyramids were built have been calculated to within five years or so.

In 2,467 BC, it would have been quite easy to find True North. You'd have to build some scaffolding, and hang a string with a heavy weight. This would hang perfectly vertically, pointing to the center of the Earth. Then you'd wait until Mizar and Kochab were vertically aligned exactly with your hanging string. Then a line from you, to the hanging string, would point due north to the horizon.

http://www.abc.net.au/science/k2/moments/s221162.htm


10-53

Milankovitch Cycles

Periods of Change (Con’t)


10-54

Milankovitch Cycles

Periods of Change (Con’t)

• Resulting change


10-55

65°N Insolation and Glacial Cycles

• Milankovitch theory suggests Earth orbital changes result in the observed 100 kyr cycle in ice ages

• Gray bars indicate interglacial periods, defined here as deviations in 5 kyr average of at least 0.8 standard deviations above mean

• Data Quinn et al. (1991), Jonathan Levine's insolation calculator and Lisiecki and Raymo (2005)

Lisiecki, L. E., and M. E. Raymo, 2005: A Pliocene-Pleistocene stack of 57 globally distributed benthic d 18O records. Paleoceanography, 20.

Quinn, T.R. et al., 1991: A three million year integration of the Earth's orbit. The Astronomical Journal, 101,

2287-2305.

Milankovitch Cycles



http://en.wikipedia.org/wiki/Image:Milankovitch_Variations.pngThis image was produced by Dragons flight from publicly available

data, and is released under the GFDL.


10-56

Milankovitch Cycles

Temperature and Ice Ages

• Comparison of Antarctic ice core temperature changes to changes in global ice volume

• Note they are highly correlated

• Red horizontal lines indicate modern temperatures and ice volume

• Note Antarctic temperature records show that the present interglacial seems to be relatively cool compared to previous interglacials

http://en.wikipedia.org/wiki/Image:Ice_Age_Temperature.pngThis image was produced by Dragons flight from publicly available

data, and is released under the GFDL




10-57

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Earth’s Annual Temperature Cycle at 900 m b 1 km / 3,300 ft

http://pm-esip.nsstc.nasa.gov/

Red = 20 Year AverageYellow = 2003 DataGreen = 2004 DataShort Yellow = 2005 Data

the sun - driving force for climate

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