lecture 15 deserts and wind action. lecture outline ideserts a)characteristics b)distribution...
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Lecture 15
Deserts and Wind Action
Lecture Outline
I DesertsA) CharacteristicsB) DistributionC) Southwest United States
i. The Great Basinii. The Colorado Plateau
IIWind ActionA) ErosionB) TransportationC) Deposition
III Conclusions
Lecture 3ii
Characteristics of Deserts
< 25 cm rain per year
sparse rugged vegetation
two climatic typesarid deserts
semiarid steppes
Distribution of Deserts
Climate ControlsSolar Radiation and Heat Transfer
Climate ControlsAtmospheric Heat Transfer
Three Cell Model
Hadley Cell
Ferrell Cell
Polar Cell
Climate ControlsOceanic Heat Transfer
Climate ControlsOceanic Heat Transfer – Thermohaline Circulation
Distribution of DesertsControlling Climatic Factors
Atmospheric Circulation
Rain Shadow
Cold Ocean Currents
Continentality
Distribution of DesertsAtmospheric Circulation
Distribution of DesertsAtmospheric Circulation
Distribution of DesertsAtmospheric Circulation - The Sahara
Distribution of DesertsRain Shadow
Distribution of DesertsRain Shadow - The American Southwest
Distribution of DesertsCold Ocean Currents
Distribution of DesertsCold Ocean Currents - The Namib
Sea Surface Temperature (oC) - 03/17/02
Naval Research Laboratory, Stennis Space Centerhttp://www.ocean.nrlssc.navy.mil/global_ncom
Distribution of DesertsCold Ocean Currents - The Namib
Distribution of DesertsContinentality - The Gobi
Deserts of the American Southwest
The Great Basin (Basin and Range)
The Colorado Plateau
Deserts of the American SouthwestWater Bodies – Arroyos
Deserts of the American SouthwestThe Great Basin
rugged mountain ranges separated by flat valleysfault-controlled topography
Deserts of the American SouthwestThe Great Basin
Desert Landforms of the American SouthwestThe Great Basin
Desert Landforms of the American SouthwestGreat Basin Landforms - Alluvial Fan
alluvial fan - an outspread, gently sloping mass of alluvium deposited by a stream, particularly in an arid or semi-arid region where a stream issues from a narrow canyon onto a plain or valley floor.
Desert Landforms of the American SouthwestGreat Basin Landforms – Bajada
bajada - a broad, gently inclined detrital surface extending from the baseof a mountain range out into an inland basin, formed by the lateral build-up of a series of alluvial fans.
Desert Landforms of the American SouthwestGreat Basin Landforms - Playa
playa - a dry, barren area in the lowest part of an undrained desert basin. playa lake - a shallow, intermittent lake in an arid region.
Desert Landforms of the American SouthwestGreat Basin Landforms - Pediment
pediment - a broad gently sloping erosion surface or plain of low relief, typically developed by running water, in an arid or semiarid region at the base of an abrupt and receding mountain front.
Desert Landforms of the American SouthwestGreat Basin Landforms – Inselberg
Desert Landforms of the American SouthwestGreat Basin Landforms Evolution
Deserts of the American SouthwestThe Colorado Plateau
beds of flat-lying sedimentary rocks
>1500m above sea level due to uplift
marked by monoclines
Deserts of the American SouthwestColorado Plateau Landforms
plateau- a relatively elevated area of comparatively flat land bounded on at least one side by cliffsmesa - a broad flat-topped hillbutte - a narrow hill of resistant rock with a flat top and very steep sides
Desert Landforms of the American SouthwestThe Colorado Plateau – Monocline
monocline - a local steepening in an otherwise uniform gentle dip
Wind Action
Erosion
Transport
Deposition
Wind ActionErosion
Wind ActionErosion - Blowout
Wind ActionErosion - Deflation
Wind ActionErosion - Ventifacts
Wind ActionTransportation
Wind ActionTransportation - Dust Storms
Wind ActionDeposition – Dunes
Wind ActionDeposition – Dune Migration
Wind ActionDeposition – Dune Morphology
Wind ActionDeposition – Controlling Factors on Dune Morphology
Wind ActionDeposition - Barchan Dunes
Wind ActionDeposition – Transverse Dunes
Wind ActionDeposition – Barchanoid Ridge Dunes
Wind ActionDeposition – Star Dunes
Wind ActionDeposition – Parabolic Dunes
Wind ActionDeposition – Longitudinal Dunes
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