Global-Regional climates

Question 1

The climate system at any place is the most
important environmental influence on the natural
vegetation, the landscape and on human activity
3 components of the climate are crucial…

Answer 1

Precipitation, thermal conditions and the wind

conditions.

Question 2

General controls of global climate

Answer 2

1. The Sun ultimately drives weather systems and the global climate, therefore, latitude plays an important role
2. Distribution of the oceans and continents, ocean
   currents and general circulation of the atmosphere also play an important role in determining climate – energy transfer
3. Presence of zones of ascent or descent of air – High pressure – descending anticyclonic conditions – dry, warm
   – Low pressure – ascending air, large clouds can grow
   – Slantwise convection
   – Map of surface pressure provides indication where ascending
   and descending air masses are located
4. Substantially different climates can be experienced within each latitudinal zone due to the complexity of influencing factors
5. Climate classification systems – Köppen’s is the
   most famous

Question 3

Coriolis effect is negligible…

Answer 3

close to the equator

Question 4

Air follows the pressure gradient…

Answer 4

along a direct path from high to low pressure

Question 5

The climate is not dominated by…

Answer 5

large circulations (anticyclones/depressions)

Question 6

Equatorial Trough…

Answer 6

Outflow from north-east and south-east trade
winds causes convergence into a region of low pressure

Intertropical convergence zones (ITCZ), part of the Hadley cell

Question 7

The easterly wave and tropical cyclones

Answer 7

• Moving troughs of slightly lower pressure
denoting zones of low-level convergence – producing heavier rain
• Important because they can develop into tropical depressions and tropical cyclones
• Tropical cyclones require high sea surface temperatures above 26˚C
• Tropical cyclones give very high rainfall intensities but are low-frequency events

Question 8

Monsoons

Answer 8

Switching of wind direction as the ITCZ moves north and south in north east and south east trade wind areas.

Largest and most intense monsoon is in Asia

Question 9

How do tornadoes form

Answer 9

Form where warm humid air becomes trapped under a
temperature inversion

The warm humid air mass breaks through the temp inversion and rises rapidly

Question 10

Why do tornadoes rotate?

Answer 10

Wind shear causes the tornado to begin rotating (not Coriolis force)
– Wind direction changes with
height
– Wind speed increases with
height

Question 11

What does tornadoes formation also cause the growth of?

Answer 11

Causes growth of substantial storm clouds (mesocyclone) some of which spawn tornados.

If the rotating mesocyclone develops sufficient strength a
funnel extends to the ground.

Question 12

Subtropical deserts

Answer 12

Position of the subtropical anticyclones (the descending part of the Hadley cells north and south of the equator)
Where ocean circulation brings cold currents and greater
subsidence – increased atmospheric stability.

Question 13

Driest, hottest deserts are found…

Answer 13

…on the western coastal regions

– Namibia, northern Chile, southern California, Africa (Sahara)

Question 14

The extent of desert around the world depend on…

Answer 14

the proportion of land mass, ocean circulation and mountain barriers

Question 15

Desert regions typically experience…

Answer 15

high winds & daytime temps and large diurnal fluctuations

Question 16

Mid-latitudes

Answer 16

Dominated by weather systems that move across the planet – weather is more variable and less predictable
than lower latitudes

Question 17

Whereas in the Hadley Cell energy transfer is dominated by convection/subsidence of air masses, in the Ferrel Cell…

Answer 17

the energy transfer is caused by movement of large weather systems

Question 18

Depressions =

Answer 18

circulating rising air at lower pressure – winds circulate anticlockwise into a depression (produces stormy conditions with wind and rain/snow)

Question 19

Anticyclones =

Answer 19

circulating subsiding air masses at higher pressure - winds circulate clockwise from anticyclones (produces calm, often sunny and in winter frosty conditions)

Question 20

Give examples of tundra climates

Answer 20

N America, Sweden, Finland, Russia, coastal

Greenland

Question 21

Tundra climates

Answer 21

– Warmest month above 0oC but below 10oC,
extremely low winter temperatures (average – 25oC Jan)
– Low precipitation (<300 mm) except coastal
Greenland (750–1100 mm)
– Weather is dominated by the prolonged winter
season with anticyclonic conditions