Desert

In a dust storm, dust can be transported across continents and oceans depositing on _____

Land, ice and wated

Drought tolerance

Leave shed during dry periods to conserve water in the stems or resinous leaf coatings that retard water loss, extensive and often very deep root systems

Cold deserts are present in ______ and _____

Siberia, Antartica

Barchan Dunes

Solitary, crescent shaped dunes

Vegetation in deserts is _____, have a ____ appearance, and have ____ leaves, which are rarely green

Spiny, swollen, tiny

Sand dunes are ____ on the leeward side and ____ on the windward side

Steeper, gently sloping

____ and ____ fans do exist in deserts

Streams, alluvial

Isolated torrential downpours cause ______ with powerful _____ because the desert can't absorb the water easily

Strong runoff, flash floods

Types of deserts

Subtropical desert, rain-shadow, coastal, continental interior, polar

Star dunes are the most complex type of dune because they form in areas where _____ varies significantly, resulting in significant vertical _____ and may remain ____ for centuries

Wind Direction, build-up, stationary

dust devil

a small whirlwind or air vortex over land, visible as a column of dust and debris.

Barchan dunes only form where wind supply is ____ and sand supply is _____

constant, limited

Deflation of a desert surface might result in this forming?

desert pavement

sand dunes

hills of sand shaped by the wind

Hadley cells are

large-scale atmospheric convection cells in the tropics, extending between the ITCZ and the tropics of Cancer or Capricorn

Polar Deserts (Cold)

occurs where precipitation is extremely low due to sinking cold, dry air. They are underlain by ice. (Northern Greenland and Siberia and Antarctica)

longitudinal dunes

-Narrow, linear sand ridges with a broadly symmetrical profile aligned parallel to the prevailing wind direction -Form from prevailing direction of wind having slight varnish

parabolic dunes

-U-shaped dunes with the horns pointing upwind due to the role vegetation plays -Develop in area of partial vegetation and along coastlines with strong winds and abundant sand

subtropical high

A belt of high pressure located at approximately 30o N and 30o S, which pushes heavy subsiding air outward toward both north and south.

dust storm

A condition in which strong winds carry dust over a large area, usually during drought conditions.

desert varnish

A dark, rusty-brown coating of iron oxide and magnesium oxide that accumulates on the surface of the rock.

transverse dunes

A series of long ridges oriented at right angles to the prevailing wind; these dunes form where vegetation is sparse and sand is very plentiful.

Gigantic _____ provide evidence for erosion in valleys and canyons

Alluvial fans

Nutrients are brought from Western African dust to fertilize _____

Amazon rainforest

The _____ in Uzbekistan has an internal delta and flows through a desert

Amu Darya

Permanent streams exist in some deserts but only when it originates in ______

Areas with temperate or tropical climates

Desert varnish is only found in _____ and forms through interaction between ____, ____, and _____ on rock surfaces

Arid climates, dust, moisture, microbes

Desert is based on an area's _____, not a _____

Aridity, temperature

____ is one of the driest places on Earth

Atacama Desert

_____ are coastal deserts

Atacama, Namib

Atacama is dry because of the ______, in the rain shadow of the _____ and close to the _____

Cold Humboldt Current, Andes, subtropical zone

Coastal deserts form along coasts with ______

Cold ocean currents

Vegetation's Main Adaptive Strategies

Drought tolerance, succulence, drought avoidance

star dunes

Dunes that are isolated hills of sand that exhibit a complex, star like form. Develop where wind patterns are changing.

formation when local small pocket of hot air at the surface rises in the cooler, less buoyant air above resulting in spinning of cooler aid

Dust devil

Wind that Carrie sediment has strong ______

Erosionad power

Drought avoidance

Escape unfavorable conditions by not existing, I.e. germination only during a narrow window of time, when enough moisture is available, maturation in a short period, then death after channeling all energy into producing seeds

Aridity not only depends on rainfall but also on the rate of ______, and where this rate is sporadic or continuous

Evaporation

Ephemeral streams

Fast flowing creeks and streams, which will dry up shortly thereafter

Only ____ are transported in dust storms

Fine fraction

In desert wind, suspended load consists of ______ sediment like dust and silt while surface load consists of _____ such as sand

Fine-grained, coarse-grained

Transverse dunes form only on _____ areas where wind is ____ and sand supply is _____

Flat, barren, constant, high

Different types of deserts depend on the _____ setting

Geological

____ are continental deserts

Gobi, Taklamakan

lag deposit

the coarse sediment left behind in a desert after wind erosion removes the finer sediment

When sand dunes migrate, ____ results

Cross-bedding

Vegetation inhibits _____

Deflation

Dust storms from Central Asian deserts fertilizes ______

Hawaiian islands

Cold ocean water cools the overlying air by absorbing ____, and the resulting cool, relatively dry offshore air becomes _____ as it blows onshore and evaporates ______

Heat, heated, moisture

Air sinks in the _____, the pressure sinks, heating the air up. The air absorbs ______ and results in dry conditions with no _____

Subtropics, moisture, clouds

Abrasion

The grinding away of rock by other rock particles carried in wind

A desert is a dry area wheee average rainfall is less than ____ per year, vegetation coves less than __% of the land surface, no permanent streams or ______ streams

25 cm, 15, ephemeral

Deflation

Lowering of the land surface by removal of the finer fraction of sediment

Longitudinal dunes form behind ____ where sand supply is _____, wind is ____ but somewhat ____

Obstacles, moderate-high, constant and strong, variable in direction

Multifaceted ventifacts

Often found in deserts due to the abrasion of wind and the change in direction of the abrading wind

Desert varnish is often used as canvas for _____

Petroglyphs

In deserts, wind has direct access to the ground due to lack of ____

Plant cover

trade winds

Prevailing winds that blow northeast from 30 degrees north latitude to the equator and that blow southeast from 30 degrees south latitude to the equator

The progression from San Francsco to Death Valley is a result of the ______

Rain shadow effect

Death Valleyis in the _____ of the Rockies and is one of the most extreme deserts, because it is _____ sea level and close to the _____

Rain shadow, below, subtropical zone

In a ____ desert, air picks up moisture, rising air cools and rain clouds form. Once air moves across mountain, air is warmer and dryer resulting in a desert

Rain-shadow

Petrogyphs

Rock carvings of animals on desert varnish

Largest desert is in ____

Sahara

________ deserts are subtropical

Sahara, Kalahari, Arabian, and Australian

Like flowing waters, wind transports sediment both as ____ and _____

Surface load, suspended load

_____ are Rain-Shadow Deserts

The Great Basin, Patagonian

Very little precipitation in the Earth's polar regions, because of the ______ and _____

The general global air circulation causes the air to be dry over these regions, cold air holds very little moisture

Central Asian Deserts

These deserts result As air moves across a continent, for long distances such as over Asia, it gradually loses moisture via rainfall and

In a _____ zone, there is a lot of deflation

Trade winds

Parabolic dunes form in areas with partial ____, are common along ____ with strong ______ with ___ sand supply

Vegetation, coastlines, onshore winds, abundant

Succluence

Water storage in thick fleshy leaves and stems, water-efficient variant of photosynthesis using CO2 that is taken up at night and stored inside leaves, spiny or toxic to protect themselves from thirsty animals