climate of arid landscapes

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Climate of Arid Landscapes 1. Low & Mid-latitude Deserts 2. Low & Mid-latitude Steppes 3. Applied: Living in the Sahel 4. Desertification Namib Desert Joshua Tree Desert Preserve The only deserts in the world that have a reliable source of water are those that lie alongside a cold ocean current What are deserts?

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Climate of Arid Landscapes. What are deserts?. 1. Low & Mid-latitude Deserts 2. Low & Mid-latitude Steppes 3. Applied: Living in the Sahel 4. Desertification. Joshua Tree Desert Preserve. Namib Desert. - PowerPoint PPT Presentation

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Page 1: Climate of Arid Landscapes

Climate of Arid Landscapes

1. Low & Mid-latitude Deserts 2. Low & Mid-latitude Steppes3. Applied: Living in the Sahel4. Desertification

Namib Desert

Joshua Tree Desert Preserve

The only deserts in the world that have a reliable source of water are those that

lie alongside a cold ocean current

What are deserts?

Page 2: Climate of Arid Landscapes

Koeppen KeyB: PE > PW: P < ½ PEh: MAT >64º FK: MAT < 64º F

B climates are clearly the most extensive climate over land

(35%)

Map of Arid Lands

Consider: Can h deserts receive > precip than k deserts and still be drier?

Page 3: Climate of Arid Landscapes

General Characteristics of BW 1. Between 15º & 30º N/S Subtropical H predominate2. West coast strong E subsidence

Exceptions to general Characteristics

1. Great Basin/Patagonia (40º)

Rain Shadow

2. Taklamakan/Turkestan/Gobi

moisture-bearing air mass

3. N. East Africa & Somalia

Asia excludes maritime air

highlands & S. Asian monsoonH

L Summer

Great Basin

Taklamakan

Weak (E) /strong (W) subsidence

Page 4: Climate of Arid Landscapes

Applied Regional Climatology: Living in the Sahel

Human response to heat1. The human thermostat2. Dehydration (15-20% of body wt.)

The Sahel is a region of & in transition (BSh)

When over 100,000 people in the Sahel died , the human consequences of climate change became a reality.

3. Adaptation Acclimatization

- low body mass, long limbs,

long nose(humidify air)

- > in blood and sweat, < heat rate

Loose cloths on a Tuareg, Algeria

Animal adaptation, Thorny Devil

Page 5: Climate of Arid Landscapes

Is the Sahel Experiencing Desertification

Advancing Deserts

1. 50 m. ac. of lost productivity/yr (1970’s) or 30 mi/yr

2. Causes of desertification- heavy settlement (>30 million)- drought/southward shift in the ITCZ- overgrazing = > albedo = absorb <

heat = < convection = stay desert- less evapotranspiration- fluctuations in global climate

- rainfall & revegetation- tied to sea surface

temperatures- Sun spot cycle?? No one answer

Basal Zone

Metabolic reserve

Page 6: Climate of Arid Landscapes

Desertification-Climate Feedback

Page 7: Climate of Arid Landscapes

Is the Sahel Experiencing DesertificationThe Many Human Causes of Desertification

Deforestation, fuel gathering in Mali

Ground water removal, Center-

pivot irrigation, Libya

Fossil water removalMore wells = more desertification, Niger

Grazing, especially goats

Agriculture: peanut production & field

abandonment

Barren circles/ year around grazing

Page 8: Climate of Arid Landscapes

Is the Sahel Experiencing Desertification

Center-pivot

Armored soil

Wind erosion

Page 9: Climate of Arid Landscapes

Applied Regional Climatology: Living in the Sahel

Desertification in Decline

Between 1984 and 1991 the area of desert has declined by

270,000 sq mi