Geol101 2006Lect17Eolian USE IN...
Transcript of Geol101 2006Lect17Eolian USE IN...
Deserts & Eolian
Geomorphology
Ch 13
Kansas, 1977“Point Of Know Return”
CD Playing:
“Best of Kansas” Dust in the Wind
Aeolian Geomorphology
• Wind = Important Agent Where There Is Little Vegetation
• Deserts • Coastal Areas• Disturbed Lands, etc.• Mars, Venus, etc.
Why Is There Wind?
• Differences in Air Pressure.Why Are There Differences in Air Pressure?• Differences in Air Temperature.
– Hot Air Rises Because It Is Lighter.• Differences in Moisture Content.
– Which Is Heavier: Moist or Dry Air?
Which Is Heavier?Moist Air Dry Air
Which Is Heavier?
• Worse Yet, This May Get Scientific.
¡Excúseme, amigo! What Are the Principle Molecular
Components of Air?
Oxygen and Nitrogen! So What, Varmint?
Which Is Heavier?
• This May Get Scientific AND Ugly.
So What!You %#@ **^%&!
Sí, Amigo. N2 and O2.The Molecular Weight of N2 = 14 + 14 or 28.
The Molecular Weight of O2 = 16 + 16, or 32.
Which Is Heavier?
• Clearly, Our Hero, Hoppy, Has Established Mental Superiority and Taken the Upper Hand in This Debate.
Git to Your Point, Partner!
The MolecularWeight of H2O Is
1 + 1 + 16 or Only 18. Less Than That of
O2 or N2!
Which Is Heavier?
• Hoppy Takes On a Superior Air as He Finishes off His Opponent in the Coop d’Grass
Oh, I Knew That!
Accordingly, Dry Air Is Heavier
Because It Has A Smaller Fraction of H2O (Water Vapor)!
Pressure Gradients Drive Wind
Coriolis Effect Deflects Flow Direction
Upper Air Map - Altitude of 500 millibar “Surface”
LLLL HHHH
LL Units are meters X
10
Upper Air Flow
LLLL HHHH
LL
Jet Stream
LLLL HHHH
LL
Why Deserts?
• Rain Shadows• Global Circulation Patterns
Gas LawsGas Laws
PPV = V = nRnRTTP = PressureP = Pressure
T = Temperature T = Temperature P & T are on opposite sides of
equation, so they change in unison
Orographic Effects
Global CirculationGlobal Circulation
EquatorEquatorSun Hot Hot
ColdCold
HadleyHadley’’s Model s Model
EquatorEquatorSun
Hot Air Rises
Cold AirSinks
Simple Convection Simple Convection Cell in Each HemisphereCell in Each Hemisphere
Better Better Model Model
EquatorEquatorSun Hot, Wet Air
Cold, Dry Air
3 Convection Cells3 Convection Cellsin Each Hemispherein Each Hemisphere
2020--3030oo
5050--6060oo
Cool, Wet Air
Warm, Dry Air
Add CoriolisEffect…
to Produce
Prevailing Winds
Better Model Better Model
Wet HotWet HotSun
3 Convection Cells3 Convection Cellsin Each Hemispherein Each Hemisphere
Dry, HotDry, Hot
Wet, CoolWet, Cool
Dry, ColdDry, Cold
Dry, Hot Dry, Hot
Dry, Cold Dry, Cold
Wet, Cool Wet, Cool
Predict WorldPredict World’’s s DessertsDesserts
BAKLAVA,
DR. KITE’S 2ND
FAVORITE DESSERT
MIDDLE EASTERN DESSERT
Donkey (2001): You know what else everybody likes? Parfaits. Have you ever met a person, you say, "Let's get some parfait," they say, “* no, I don't like no parfait"? Parfaits are delicious.
"Now tell me, where are the others?!" (Lord Farquaad) "Eat me!" (Gingerbread man, spitting at him)
DESSERTS OF THE WORLD
Map Source: US CIA
Mmmm…Doughnuts
Images Sources for Desserts of the WorldParfait –
http://www.dcmarketingtools.com/gallery2/HW-catering.htmlBaklava –
http://www.cariskitchen.com/images/94HFBaklava.jpgApple Dumplin’s -
http://www.cariskitchen.com/images/94HF%20Apple%20Dumplings%20with%20Caramel%20Cinnamon%20Sauce.jpg
Black Forest Cake –http://www.cariskitchen.com/images/94PfaelzerBro%20Black%20Forest%20Cake.jpg
Moon Pie –http://www.moonpie.com/single/prod_level1.asp
Gingerbread Manhttp://coco.raceme.org/films/shrek/quotes/others.php
Donuts –http://witfits.blogspot.com/2005_03_01_witfits_archive.html
Summer Model
Thermal EquatorThermal Equator
SunEasterlies
Westerlies
Easterlies
““RealReal”” EquatorEquator
DESERTS OF THE WORLD
Antarctica = Desert
Why DidnWhy Didn’’t USA Wait IN t USA Wait IN 2003 to See if UN 2003 to See if UN Could DisarmCould DisarmIraq?Iraq?
EquatorEquatorSun
Climatic Considerations!Climatic Considerations!
Iraq Zagros Mts
P. Gulf
WinterModel
Sun
Easterlies
Westerlies
Easterlies
““RealReal”” EquatorEquator
Thermal EquatorThermal Equator
Sandstorm Iraq, Iran & Persian Gulf
visibleearth.nasa.gov/cgi-bin/
viewrecord?7746
Sandstorm Iraq, Iran & Persian Gulf
visibleearth.nasa.gov/cgi-bin/
viewrecord?7746
Dust StormIraq
March 2003
Dust in Deep-Sea Sediments
Aeolian Sediment Sources:Kite Stream, Antarctic Polar Desert
J.S. Kite Photo
Dry Bed of Kite Stream
J.S. Kite Photo
Wind-Blown Silt (Loess) Over Dry River Bed, New Zealand
Loess
Loess on Outwash Terrace, New Zealand
Mississippi River
System Loess
Last Ice Age~20,000 Years Old
Antarctica: Ventifacts & Desert Pavement
Ventifact on Deflation Surface
Aeolian Sediments
DustDust
SandSand
Kill Devil Hill, Kitty Hawk, NC
• Vegetated, Stable
J.S. Kite Photo
Jockeys Ridge, Kitty Hawk, NC
http://www.nature.nps.gov/nnl/Registry/USA_Map/States/NorthCarolina/NNL/NH/index.cfm
• Unvegetated, Unstable
NPS Photo
Dune Field, Victoria Valley, AntarcticaGlacier
Transverse Dunes
Dune in Later SlideJ.S. Kite Photo
Cross-Bedding in Dune
Wind Direction
Wind Direction
Sand Dune, Victoria Valley, Antarctica
J.S. Kite Photo
Lee Slip-Face of Dune, Victoria Valley
J.S. Kite Photo