The Amazon Rainforest Flashcards
How large is the rainforest?
6 million km2
How much of the rainforest is in Brazil?
70%
What other countries does the rainforest extend into?
Peru, Ecuador, Venezuela, Columbia, Bolivia, Guyana
What are the average annual temperatures like?
High - 25 to 30 degrees
What are the seasonal differences in temperature?
Small
What is the result of cloud cover?
Temperatures kept to 33 degrees max
What is the average rainfall?
over 2000mm
How much precipitation is recycled by evapotranspiration?
50-60%
Where is water lost?
River flow and export of atmospheric vapour to other regions
Where does the inward flux of moisture come from?
Atlantic Ocean
How is precipitation distributed throughout the year?
Evenly
What type of rain is it?
High intensity convectional rainfall
How much rain is intercepted by trees?
10% - a lot
Intercepted rain accounts for what % of evaporation?
20 - 25%
Why is evapotranspiration high?
High temperatures, abundant moisture, dense vegetation
What feedback loop is strong?
evapotranspiration-precipitation
Where doe most evaporation come from?
Intercepted moisture from leaf surfaces
How do plants replace lost moisture from transpiration?
Soil via the roots
Why is run-off rapid?
high and intense rainfall and well-drained soil
What causes a short peak in river discharge?
seasonal distribution of rainfall
What forms of humidity are high?
absolute and relative (the ratio of mass of vapour in air against how much is needed to saturate it)
Why is there significant water storage in soil?
High rainfall and deep soil
What role do trees play in the water cycle?
absorb and store water then release it via transpiration
What geology is dominant?
impermeable crystalline rocks
What is the result of impermeable rocks?
minimal water storage capacity so rapid run off
Examples of porous rocks:
limestone and sandstone
Describe the relief
mostly lowland with gentle relief but steep Andes range in the west
What is the effect of lowland on the water cycle?
overland flow and throughflow
What is the effect of the Andes on the water cycle?
rapid run off
Example of a floodplain
Pantanal
What do floodplains do?
store water
What is the result of high temperatures on the water cycle?
high evapotranspiration
What is the result of strong convection on the water cycle?
high humidity, thunderstorm clouds, intense precipitation
What processes continually cycle water?
evaporation, transpiration, precipitation
How much is was deforested on average each year between 1970 and 2013?
17,500 km2
How much primary forest has been destroyed since 1970
1/5
What has happened to the rate of deforestation in recent years?
slowed
What is the result of converting rainforest to grassland on the water cycle?
increases run off by a factor of 27
How much of rainfall that falls on grassland goes into rivers?
half
Why are trees crucial to the water cycle?
extract moisture from soil, intercept rainfall, release moisture to atmosphere, stabilise albedo and ground temperatures