1.6. Factors Driving Change in Magnitude of Water Stores Flashcards
What is evaporation?
Occurs when liquid water changes state into a gas, becoming water vapour
What does evaporation do?
Increases amount of water stored in atmosphere
How do rates of evaporation change?
By location and season
What will a large supply of warm dry air cause?
High rates of evaporation
What is accumulation?
freezing
What is ablation?
melting
What do accumulation and ablation do?
Change the amount of water stored in the cryosphere
Balance changes with temps
What happens during cold periods?
Inputs > outputs
(water transferred as snow and less through melting)
What does the earth go through?
Natural warming and cooling by changes in the earth’s orbit every 100,000 years
Changes can occur in shorter timescales e.g. seasonal and industrial revolution
What is happening to most glaciers?
They’re shrinking
How may years ago was the peak of the last ice age and how much of the earth’s surface was covered in ice sheets?
- 21,000 years ago
- 1/3 of the earth’s surface
How much lower were sea levels at the peak of the last ice age
100m lower
What could melting of Antarctica and Greenland ice sheets cause sea levels to do?
rise by 60m
+ve feedback of climate change
Rising sea levels will make ice sheets break which will cause further melting
What happened 3 million years ago?
Sea levels were 50m higher than today (warmer period)
When does condensation occur?
- When water vapour becomes a liquid and loses energy to its surroundings.
- When water condenses, it releases latent heat.
- Happens when air containing water vapour cools to its dew point e.g. when temps fall at night as heat is lost to space.
- Water droplets can stay in the atmosphere or move to other subsystems.
What has the greatest control on condensation?
Temperature -> lots of water vapour and decreased temps = high condensation
What is frontal rain?
Where less dense warm air meets denser cool air, the warm air rises and cools -> vapour condenses to form frontal rain
What is relief rain?
Where warm air meets mountains, it’s forced to rise and cool -> vapour condenses to form relief rain
What is convectional rain?
When the sun heats up the ground, moisture rises as a column of warm air. This then cools and vapour condenses to make convectional rain (global atmospheric rain).
