1.2 the global hydrological cycle

Question 1

what is a residence time?

Answer 1

the time that water is held in a store

Question 2

how much of earth’s water is freshwater?

Answer 2

2.5%

Question 3

what is the residence time for atmospheric water?

Answer 3

1.5 weeks

Question 4

what is the residence time for glaciated water?

Answer 4

1,000 years

Question 5

what type of system is the global hydrological system and what does it mean?

Answer 5

closed system
inputs = outputs

Question 6

which stores are depleting?

Answer 6

glaciers

Question 7

how does solar radiation drive the global hydrological cycle?
(6 steps)

Answer 7

1. energy from the sun heats water
2. evaporation increases as the climate warms
3. moisture levels in the atmosphere increase
4. air cools
5. condensation of water vapour and clouds form
6. precipitation occurs

Question 8

how does gravitational potential energy drive the global hydrological cycle?
(2 steps)

Answer 8

1. water moves by gravity
2. surface run off and groundwater flow transports water to the sea

Question 9

where is most freshwater stored?

Answer 9

cryosphere as frozen water

Question 10

what is the global water budget?

Answer 10

difference between inputs and outputs

Question 11

what is the relationship between inputs and outputs in oceans?

Answer 11

outputs exceed inputs

Question 12

what is the relationship between inputs and outputs in land masses?

Answer 12

inputs exceed outputs

Question 13

why are the tropics important in the global water budget?

Answer 13

steep angle of the sun intensifies radiation = high evaporation
water vapour is transferred to the ITCZ
air rises and cools due to convection currents
clouds form

Question 14

why are the polar regions important in the global water budget?

Answer 14

drives the thermohaline circulation

Question 15

what is the process of thermohaline circulation?
(3 steps)

Answer 15

1. polar ocean water is colder and denser than tropical water - sinks
2. the sinking cold water draws in the warm water from above and the tropics
3. water movement from the tropics draws cold water from the ocean to be warmed

Question 16

what is fossil water?

Answer 16

ancient stores of water beneath polar regions and deserts