Dynamic Earth Desert/Wind Ch 17

What officially defines a desert, in simplest precipitation-based definition?

<25 cm/yr (10in./yr)

How many US states, of the contiguous 48, have a desert?

12

~% of land in deserts

25%

Five different causes of deserts, and highlighted examples (given for three)

Subtropical desert (descending at 30 degrees) ex Sahara

Rain shadow (moisture lost over mountainsj ex Great Basin

Continental interior: Gobi

Coastal: (cold coastal upwellings) ex Atacama driest place on earth non-polar

Polar: (cold air holds little moisture + descending air

How rising vs sinking air affects atmospheric moisture and precipitation vs dry

Rising air cools and becomes saturated, causes rain/snow, causes rain and snow

Sinking air drier

Why are there deserts at ~ 30 degrees north and south

Equatorial belt

What is the driest desert on Earth (non-polar)? What continent is it on?

Atacama Desert in South America

On what side are the dunes steepest? (Upwind or downwind)

Downwind side

Be able to recognize barchan, and transverse dunes in pictures or diagrams

Be able to determine wind direction based on pictures of dunes

Playas

Evaporated desert lake

The role of water in desert landform formation

Leads to water erosion which creates cliff retreat