A.D. Tropical Environments - Influences on Climate Flashcards
What are the 5 factors that influence climate?
- Latitude
- Ocean currents
- Continentality
- Altitude
- Relief
What is a climate?
general atmospheric condition in an area over a long period of time - 30 years
How are tropical environments classified?
- Rainforest climate
- Monsoon climate
- Savannah climate
What is an air mass?
- huge volume of air
- with same humidity and temperature
- in areas they cover, they influence climate and create biomes
Where do source areas of air masses appear?
below air masses
What affects the humidity and temperature of source areas?
whether they are over land or sea
latitude - close to pole - colder
What are the two types of sources classified by latitude?
Equatorial
Subtropical
What are the characteristics of equatorial air masses?
- both continental and maritime are without season, 25 degrees
- both moist and neutral
What are the characteristics of subtropical air masses?
- continental 15,25 degrees
- maritime 18,25 degrees
- stable to dry, neutral
What is the ITCZ?
Intertropical Convergence Zone
-a belt of low pressure around the equator where the trade winds meet
What are the characteristics of the ITCZ?
- calm conditions due to trade winds not crossing the equator
- high moisture, frequent precipitation, thunderstorms
- amount of rainfall depends on the sun
What is another zone of similar conditions to ITCZ?
Zaire Air Boundary
How does the ITCZ work during the year?
- at the equator there is an area of intense heating leading to rising air and moisture - low pressure area
- from January to July:
1. Tm air mass from the Gulf of Guinea warms up and forms a large cumulonimbus clouds
2. Tc warm desert air moves high temperatures upwards
3. As Tm moves over land it loses source of moisture and drops it
4. Tc then moves back down before January
How do subtropical anticyclones affect weather?
high pressure brings clear, dry, calm weather
brings light winds
colder foggy winters
What causes ocean gyres?
- trade winds move ocean currents
- regions of convergence are formed where water piles up, forming small hills
- this small elevation creates a difference in pressure where the centre has higher pressure
- the pressure gradient pushes water down towards lower pressure
- geostrophic flow causes the water to flow in a circle forming gyres
What are the examples of gyres?
North Pacific Gyre, South Pacific Gyre, North Atlantic Gyre, South Atlantic Gyre, Indian Ocean Gyre
What impacts do gyres have?
- West coast of Northern hemisphere is warmer
- East coast of Northern Hemisphere is cold and dry
What determines the temperatures the winds bring?
where they originate
-over the sea: warmer in winter, colder in the summer because of the lag time
What is a monsoon?
pattern of seasonal winds that experiences a reversal
Describe the Indian monsoon:
- moist air evaporating from the ocean coming across India
- winds driven by temperature differences over land and ocean
What is the difference between a monsoon summer and winter?
- summer: when the land is warm, the air expands and draws in the moisture from the ocean water
- winter: very cold conditions causes moisture to draw back into the oceans
What is an ENSO phase?
-a cycle that causes extreme conditions, swings from La Niña to El Niño, takes around 4 years to cycle
What happens during the neutral phase of ENSO?
- steady winds blow over the Pacific from east to west
- there they pile up warm water
- leaves the east cold
- drives the Walker Circulation
What happens during a La Niña?
- trade winds blow harder
- it cools the east pacific even more
- increases the east to west temperature difference
- causes a feedback loop
- higher risk of flooding, tropical cyclones in Australia
