Aeolian Geomorphology. Dust in the Wind. Deserts & Eolian Geomorphology. Ch 13. Kansas, 1977

Transcription

1 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.

2 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? Moist Air Which Is Heavier? Dry Air Which Is Heavier? Oxygen and Nitrogen! So What, Varmint? Excúseme, amigo! What Are the Principle Molecular Components of Air? Worse Yet, This May Get Scientific.

3 Which Is Heavier? So What! You **^%&! Sí, Amigo. N 2 and O 2. The Molecular Weight of N 2 = or 28. The Molecular Weight of O 2 = , or 32. This May Get Scientific AND Ugly. Which Is Heavier? Git to Y r Point, Partner! The Molecular Weight of H 2 O Is or Only 18. Less Than That of O 2 or N 2! Clearly, Our Hero, Hoppy, Has Established Mental Superiority and Taken the Upper Hand in This Debate. Which Is Heavier? Oh, I Knew That! Accordingly, Dry Air Is Heavier Because It Has A Smaller Fraction of H 2 O (Water Vapor)! Hoppy Takes On a Superior Air as He Finishes off His Opponent in the Coop d Grass

4 Pressure Gradients Drive Wind Coriolis Effect Deflects Flow Direction Upper Air Map - Altitude of 500 millibar Surface L H L L H Units are meters X 10

5 Upper Air Flow L L H L H Jet Stream L L H L H Why Deserts? Rain Shadows Global Circulation Patterns

6 Gas Laws PV V = nrt P = Pressure T = Temperature P & T are on opposite sides of equation, so they change in unison Orographic Effects Global Circulation Cold Sun Hot Equator

7 Hadley s s Model Cold Air Sinks Sun Hot Air Rises Equator Simple Convection Cell in Each Hemisphere Better Model Sun Warm, Dry Air Hot, Wet Air Cool, Wet Air o o Equator Cold, Dry Air 3 Convection Cells in Each Hemisphere Add Coriolis Effect to Produce Prevailing Winds

8 Wet, Wet, Cool Cool Better Model 3 Convection Cells in Each Hemisphere Dry, Cold Wet, Cool Dry, Hot Sun Wet Hot Dry, Hot Predict World s Desserts Dry, Cold MIDDLE EASTERN DESSERT BAKLAVA, DR. KITE S 2 ND FAVORITE DESSERT DESSERTS OF THE WORLD 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. Mmmm Doughnuts "Now tell me, where are the others?!" (Lord Farquaad) "Eat me!" (Gingerbread man, spitting at him) Map Source: US CIA

9 Images Sources for Desserts of the World Parfait Baklava Apple Dumplin s - lings%20with%20caramel%20cinnamon%20sauce.jpg Black Forest Cake 20Forest%20Cake.jpg Moon Pie Gingerbread Man Donuts Summer Model Sun Westerlies Easterlies Easterlies Thermal Equator Real Equator TEST 2 CURVE + 3 points to score now (24 March) on line.

10 DESERTS OF THE WORLD Antarctica = Desert Orographic Effects Why Didn t t USA Wait IN 2003 to See if UN Could Disarm Iraq? Sun Iraq Zagros Mts P. Gulf Equator Climatic Considerations!

11 Winter Model Easterlies Westerlies Easterlies Real Equator Sun Thermal 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

12 Dust Storm Iraq March 2003 Dust in Deep-Sea Sediments

13 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

14 Loess Loess on Outwash Terrace, New Zealand Mississippi River System Loess Last Ice Age ~20,000 Years Old Deflated Stream Bed

15 Desert Pavement Wind Transportation of Sand Saltation Antarctica: Ventifacts & Desert Pavement

16 Ventifact on Deflation Surface Aeolian Sediments Dust Sand Coppice Dunes

17 Coppice Dunes, California Deflation Surface Jockeys Ridge, Kitty Hawk, NC Unvegetated, Unstable NPS Photo Vegetated, Stable Kill Devil Hill, Kitty Hawk, NC J.S. Kite Photo

18 Dune Field, Victoria Valley, Antarctica Glacier Transverse Dunes J.S. Kite Photo Dune in Later Slide Cross-Bedding in Dune Wind Direction Sand Dune, Victoria Valley, Antarctica J.S. Kite Photo Wind Direction

19 Wind Direction Lee Slip-Face of Dune, Victoria Valley J.S. Kite Photo Barchan Dune, Death Valley Monster Sand Dune Variable Wind Direction Saudi Arabia