4.1 Introduction to water systems

Question 1

what kind of radiation drives the hydrological cycle

Answer 1

solar radiation

Question 2

what fraction of the Earths water storage does fresh water make up

Answer 2

a small fraction (approximately 2.6% by volume)

Question 3

storages of the hydrological cycle

Answer 3

• atmosphere
• organisms
• soil
• oceans
• groundwater
• lakes
• rivers
• glaciers
• ice caps

Question 4

transformation flows within the hydrological cycle

Answer 4

( a change in the state of water during the movement process)
- Evaporation: Water changing from liquid to gas.
- Transpiration: Water vapor released from plants.
- EVT (evotranspiration) = most important aspect of water loss as its about 100% of annual percipitation in arid areas, and 75% in humid areas
- Condensation: Water vapor turning into liquid droplets.
- Sublimation: Ice changing directly to water vapor.

Question 5

transfer flows within the hydrological cycle

Answer 5

( the movement of water from one storage to another without changing its state)

• Surface runoff: Water flowing over land surfaces into streams and rivers.
• Infiltration: Water seeping into the ground.
• Stream flow/currents: Movement of water in rivers and oceans.

Question 6

human impacts on the hydrological cycle A

Answer 6

Agriculture
- Irrigation diverts water from natural water bodies, altering local water balances.
- Overuse of groundwater for irrigation can lead to aquifer depletion.
- Agricultural practices can increase surface runoff and soil erosion.

Question 7

human impacts on the hydrological cycle D

Answer 7

Deforestation
- Reduces transpiration and increases surface runoff.
- Can lead to increased flooding and decreased water quality.

Question 8

human impacts on the hydrological cycle U

Answer 8

Urbanisation
- Increases surfaces that dont let water through, reducing infiltration and increasing surface runoff.
- Can lead to urban flooding and decreased groundwater recharge.

Question 9

Ocean circulation systems

Answer 9

driven by differences in temperature and salinity that affect water density. the resulting difference in water density creates a global “conveyor belt” of ocean currents that distributes heat around the world, so affecting the climate.

Question 10

The Ocean Conveyor Belt

Answer 10

• Surface currents carry warm water from the equator towards the poles.
• As water cools near the poles, it becomes denser and sinks.
• Deep ocean currents carry cold water back towards the equator.
• This cycle helps distribute heat globally, influencing climate patterns.

Question 11

inputs and outputs of the hydrological cycle

Answer 11

• Primary input: Solar radiation driving evaporation.
• Outputs: Water leaving the system (e.g., deep groundwater storage).

Question 12

link between the hydrological cycle and climate

Answer 12

• Water vapor is a greenhouse gas, meaning it traps heat in the Earth’s atmosphere. As temperatures rise due to other greenhouse gases (like CO₂), more water evaporates, increasing the amount of water vapor in the atmosphere.
  This amplifies the greenhouse effect, causing further warming. This is a positive feedback loop.
• Cloud formation increases global albedo and therefore lowers temperature. BUT cirrus clouds (low, thin) trap heat (infrared radiation) and lead to higher temps, contributing to gh effect.
• Ocean currents distribute heat, shaping regional climates.