Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Arid And Semi Arid > Hot Arid And Semi-Arid Climates > Flashcards

Hot Arid And Semi-Arid Climates Flashcards

(68 cards)

Start Studying
1
Q

HOT ARID AREAS

A
  • less than 250mm of rain a year
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

HOT ARID EXAMPLES

A
  • Cairo, Egypt: mean annual rainfall of 33mm
  • Areas of Atacama desert have experienced no rainfall at all
  • Luderitz, Namibia: total average rainfall in a year is 125mm
  • Khartoum, Sudan: total average rainfall in a year is 161.5mm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

GOBI DESERT

A
  • largest Asian desert
  • covers Mongolia and China
  • surrounded by Mongolian grasslands &;Altai mountains
  • covers 800 km north-west
  • lies in a rainshadow caused by Himalayas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

ATACAMA DESERT

A
  • in South America
  • driest in the world; no rain from 1570-1971
  • average rainfall is 1mm
  • Arica & Iquique get 1-3mm in a year
  • located between Andes & Chilean coast range mountain chains
  • day temp: 40 degrees
  • night temp: 5 degrees
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

SAHARA DESERT

A
  • in North Africa
  • worlds largest hot desert
  • 3.6 million miles big
  • half of it gets less than 1 inch of rain a year
  • covers big parts of Chad, Libya, Algeria, Mali
  • bordered by Atlantic on West
  • bordered by Atlas Mountains & Med Sea on North
  • bordered by Red Sea on East
  • bordered by Niger River & Sudan on South
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

TROPIC OF CANCER

A
  • line of latitude in northern hemisphere
  • approx 23.5 degrees north of equator
  • Sun’s rays appear directly overhead at local noon
  • marks northern boundary of tropics
  • passes through Hawaii
  • passes through parts of central USA
  • passes through Northern Africa
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

TROPIC OF CAPRICORN

A
  • line of latitude in Southern Hemisphere
  • goes around Earth at approx 23.5 degrees south of equator
  • southernmost point on Earth where Sun’s rays are directly overhead at local noon
  • passes mainly thought water
  • crosses through Rio, Madagascar, Australia, Brazil
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

LOCATION OF DESERTS

A
  • cover 25-30% of earths land surface
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

SEMI- ARID DESERT

A
  • between 250-500mm of rain a year
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

SEMI-ARID EXAMPLES

A
  • Great Basin, North USA: 300mm of rain a year in East

- N’Djamena, Chad: annual precipitation of 580mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

MOJAVE DESERT

A
  • smallest in USA
  • lies between 1500m above sea level. Is 86 m below sea level
  • gets between 50-330mm of rain per year
  • temp as high at 49 degrees in summer
  • temp can be below 0 in winter
  • plants adapt; Joshua tree found on edge of desert. Creosote bush is common
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

WHAT DO PLANTS NEED TO GROW

A
  • nutrients
  • heat
  • water
  • Sun
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

WHAT ARE 3 CHARACTERISTICS OF DESERTS

A
  • Climate:
    Rainfall= low when climate =hot
  • Soil:
    Dry, sandy, lack of organic matter, thin, poorly developed
  • Vegetation:
    Xerophytes adapt to conditions, plants have long roots, leaves are small &tough, vegetation found near oases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

VEGETATION IN A DESERT

A
  • density = low
  • desert soils are poor, alkaline
  • salts are common within soil. Plants that can handle soil are halophytic- eg, saltbush
  • when it rains vegetation changes. Seeds from last period of rainfall germinate & blossom
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

PLANTS IN A DESERT

A
  • adapt to high temps
  • growth is limited by high levels of evaporation or transpiration
  • lots have long tap roots that burrow down up to 15m into ground to reach an underground water supply. Known as xerophytic plants
  • plants are normally small. Gives hem smaller SA & reduces transpiration
  • leaves are replaced by thorns; give more protection
  • leaves are replaced by small wax cuticles; reduces rate of transpiration
  • aqueous tissue is fleshy & stores water. Common in cacti
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

HOW DO CACTI ADAPT IN A DESERT

A
  • known as succulents
  • they absorb & store water in their tissue
  • have low rate of transpiration
  • eg cottontop cactus
  • eg barrel cactus
  • eg beavertail cactus
  • eg beavertail prickly pear
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

ESSAY QUESTION:

‘Outline the characteristics of a desert’ (6)

A
  • climate:
  • soils
  • vegetation
  • LINK ALL 3 FACTORS TOGETHER
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

WHAT SORT OF EVAPORATION IS THERE AT THE EQUATOR

A
  • lots of evaporation is at the Equator
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

WHAT HAPPENS WHEN THERES HIGH PRESSURE

A
  • no clouds

- no rain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

WHAT IS THE WEATHER LIKE IN THE TROPICS

A
  • dry

- due to the tri- cellular model

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

WHAT INFLUENCES THE TEMPERATURE IN ARID & SEMI- ARID ENVIRONMENTS

A
  • latitude

- distance from the sea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

HOT ARID LOCATIONS

A
  • occur in centre of desert areas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

SEMI- ARID LOCATIONS

A
  • occur on margins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

A.A.MILLER’S ARIDITY THEORY

A
  • said deserts had areas with mean annual rainfall of less than 250mm
  • distinction between hot deserts & mid- latitude deserts
  • said hot had no month with a mean temp of less than 6 degrees
  • most hot are located in latitudes from 15 to 30 degrees
  • said mid- latitude have a cold season with at least 1 month with a mean of temp of less than 6 degrees. Include Great Basin of N.USA & Gobi
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
W.KÖPPEN’S THEORY
- based on P:Etp balance - arid climates are shown by letter B - BW: desert climate. Annual rainfall is less than 50% of Etp value - BS: steppe climate. Annual rainfall is 50-100% of Etp value
26
EXAMPLE OF KÖPPEN’S BW
- hot arid environment - a hot arid environment follows Köppen’s BW desert climate - means annual rainfall is less than 50% of the Etp value
27
EXAMPLE OF KÖPPEN’S BS
- semi-arid environment - a semi-arid environment follows Köppen’s BS steppe climate - means annual rainfall is between 50-100% of the Etp
28
HOW TO CALCULATE KÖPPEN’S DEGREE OF ARIDITY
- MULTIPLY average annual temperature in degrees by 20 - ADD: - 280 if 70% of more of total rainfall is in April-September in n.hemisphere or October-March in s.hemisphere - 140 if 30-70% of total rainfall is received during applicable time - 0 if less than 30% of total rainfall is received during applicable time
29
PRECIPITATION + MOISTURE IN HOT ARID ENVIRONMENTS
- annual precipitation is less than 0.2 times the potential evapotranspiration - precipitation: v.low - little moisture available for plant growth - rainfall is less than 250mm - in some areas there’s been no rain at all
30
PRECIPITATION + MOISTURE IN SEMI- ARID ENVIRONMENTS
- annual precipitation is 0.2-0.5 times the potential evapotranspiration - precipitation is low - moisture is available for plant growth
31
LYSIMETER
- the way in which actual evapotranspiration is measured | - also measured using a pan of soil & vegetation
32
ISOHYET
- a line of equal precipitation on a map
33
WHAT DETERMINES ARIDITY IN AN AREA
- depends on amount of precipitation | - depends on effectiveness of precipitation; moisture available for plant growth
34
WHAT THINGS INCREASE THE AMOUNT OF EVAPORATION LOST
- high temps - direct sun - strong desiccating winds
35
CENTRAL SAHARA
- continental area - v.high diurnal temp ranges - mainly exceed 30 degrees - daytime temps are highest in world - shade temps above 50 degrees - eg 1922: Aziza, Libya: 58 degrees - eg Salah, Algeria: July has mean temp of 37 degrees
36
COASTAL AREAS
- eg Namib - eg Atacama - climates are influenced by sea + cold ocean currents - have cooler summers - eg Walvis Bay, Namibia: mean temp of hottest month is only 19 degrees. BUT: humidity is v.high
37
HORSE LATITUDES
- where hot arid areas lie - areas of sub-tropical high pressure systems - roughly 30-35 degrees north & south of equator - areas of descending air - have gentle pressure gradients
38
CLIMATES IN HOT ARID + SEMI- ARID ENVIRONMENTS
- both have similar climates
39
SEMI- ARID CLIMATES
- areas near Equator have a transitional climate with savannas. Summer rainfall happens due to low pressure & monsoon - areas on mid- latitude side have transitional climate on poleward side with Mediterranean climate. Have winter rainfall
40
HOT ARID CLIMATE
- has little seasonality | - rare, extreme rainfall occurrences can happen in any season
41
PRESSURE + WINDS
- causes aridity in deserts - air around tropics of Cancer & Capricorn is dry - this is a zone of high air pressure where air sinks - air at Equator rises + cools + condensation forms rain - air moves north + south until it gets to 30 degrees north + south of equator where it sinks - this air is dry + no condensation can form - known as Hadley Cell
42
COLD OCEAN CURRENTS
- causes aridity in deserts - most hot arid + semi- arid areas occur on west coast of continents with a cold ocean current offshore - when onshore winds blow onto west coasts of deserts they are cooled for condensation to occur over current, leads to FOG hanging in air near surface - coastal places have foggy days + high humidity when winds are onshore - condensation removes moisture from air - foggy air moves inland, leads to water droplets evaporate
43
RELIEF + RAINSHADOW
- causes aridity in deserts - small amounts of orographic rainfall + rainshadow happens in deserts - low areas in lee of mountains are v.dry. Eg Turfan Basin, China - some deserts form in rainshadow of mountains. Eg Atacama desert is located in the rain shadow of the Andes - air is forced to rise over mountains, air cools + condensation occurs - rain falls over mountains - dry air sinks down other side of mountain
44
WHAT HAPPENS TO SEA + LAND IN DAY
- high pressure causes a colder sea | - sea breeze leads to low pressure + warmer land
45
WHAT HAPPENS TO SEA + LAND AT NIGHT
- high pressure causes colder land | - sea breeze causes low pressure + warmer sea
46
TEMPERATURE
- rain isn’t common in deserts - when it does it can cause FLASH FLOODS - eg. Parts nearest Equator where occasional convectional storms occur in summer heat
47
LATITUDE
- influences temp in deserts - hot arid + some semi area have overhead Sun in summer - leads to EXTREMELY HIGH TEMPS - 21st June: Sun is overhead Tropic of Cancer - 22nd December: Sun is overhead Tropic of Capricorn - there’s a TEMP LAG as temp builds up so hottest + coolest month is a month later - tropical deserts: Sun is never v.low. Wingers are hot + so are summers - length of day is longer in summer away from Equator
48
ALTITUDE
- influences temp in deserts - air is thinner + has less water vapour + dust to absorb Earths LW radiation - this causes temp to decrease to 0.6 degrees every 100m of height gained - contributes to cooler temps at Keetmanshoop, Namibia
49
DISTANCE FROM SEA
- influences temp in deserts - when water heats + cools slower than land coastal areas have warmer winters + cooler summers than in inland areas - known as maritime influence as air from sea brings temps of sea to land - continental areas don’t experience this effect + land heats up fast in summer + cools fast in winter - continental areas in hot deserts have v.hot summer temps. Eg Salah, Algeria: July mean temp is 37 degrees
50
DAY THAT THE SUN IS OVERHEAD THE TROPIC OF CANCER
- 21st June
51
DAY THE SUN IS OVERHEAD THE TROPIC OF CAPRICORN
- 22nd December
52
MARITIME INFLUENCE
- when air from sea brings temp of sea to the land
53
COLD OCEAN CURRENTS
- influences the temp in deserts - there are cold ocean currents off coasts of hot deserts - are bodies of water moving through oceans from areas nearer Poles to areas near Equator - winds that blow over cold Benguela current off Namibia coast are chilled by contact with current. They carry cooler air onto land. This lowers temp on coastal strip
54
LACK OF CLOUD
- influences temp in deserts - desert air has v.low relative humidity. So skies are cloudless. Leads to extreme DIURNAL TEMP - in hot deserts temp can be 50 degrees in summer shade - at night: without clouds temp drop to 15 degrees in summer + 5 in winter - low night time temp can lead to condensation of water vapour. Forms dew. Helps weathering process
55
RELATIVE HUMIDITY
- how much humidity there is in the air | - compared to how much there could be
56
ABSOLUTE HUMIDITY
- measure of water vapour (moisture) in air | - doesn’t matter what the temp is
57
POTENTIAL EVAPOTRANSPIRATION
- amount of evaporation that would occur if a sufficient water source was available
58
ACTUAL EVAPOTRANSPIRATION
- quantity of water removed from a surface due to evaporation + transpiration
59
2 COOL COASTAL DESERTS
- Atacama | - Namib
60
10 SUBTROPICAL DESERTS
- Mojave, California - Sonoran, N.USA - Chihuahuan, N.USA. Extends into parts of New Mexico, Texas + southeastern Arizona - Sahara, N.Africa. Covers large parts of Algeria, Chad, Egypt, Libya, Mali, Niger, Mauritania - Kalahari, S.Africa. Covers most of Botswana - Arabian, W.Asia. Covers from Yemen to Persian Gulf + Oman to Jordan + Iraq - Thar, Rajasthan - Great Sandy, NW of W.Australia - Gibson, W.Australia - Great Victoria, S.Australia
61
7 COLD WINTER DESERTS
- Colorado, California - Patagonian, Argentina - Iranian, Iran - Kyzyl-Kum, Kazakhstan + Uzbekistan - Kara-Kum, Turkmenistan - Taklamakan, Central Asia, China - Gobi, Mongolia + China
62
DIURNAL TEMPERATURE RANGE DEFINITION
- difference between daily max temp + daily min temp
63
CAUSES OF CHANGES IN DIURNAL TEMPERATURE RANGE
- cloud cover - urban heat - land use change - aerosols, greenhouse gases
64
DIURNAL TEMPERATURE RANGE DEFINITION
- difference between daily max temp + daily min temp
65
CAUSES OF CHANGES IN DIURNAL TEMPERATURE RANGE
- cloud cover - urban heat - land use change - aerosols, greenhouse gases
66
DO ALL CONTINENTS HAVE A DESERT
- no - all continents do - except Europe
67
WHY DO DESERTS TEND TO BE LOCATED IN THE WEST
- due to Coriolis effect
68
HYPER-ARID DEFINITION
- when areas have a mean annual precipitation value of less than 100mm

Arid And Semi Arid (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions