1.c. The carbon and water cycles have distinctive processes and pathways that operate within them. Flashcards
What is the water balance equation?
(The processes of the water cycle)
Precipitation = evapotranspiration + streamflow +/- storage
That precipitation is equal to evapotranspiration and streamflow, plus or minus water entering or leaving storage.
What does the water balance equation summarise?
(The processes of the water cycle)
Summarises the flows of water in a drainage basin over time.
What are the 7 principle flows in the water cycle?
(The processes of the water cycle)
Precipitation.
Evaporation.
Transpiration.
Run-off.
Infiltration.
Percolation.
Throughflow.
What is precipitation?
(Precipitation)
(The processes of the water cycle)
Water and ice that falls from clouds towards the ground.
It takes several forms: most commonly rain and snow, but also hail, sleet and drizzle.
How does precipitation form?
(Precipitation)
(The processes of the water cycle)
When vapour in the atmosphere cools to its dew point and condenses into tiny water droplets or ice particles to form clouds.
Eventually these droplets or ice particles aggregate, reaching a critical size and leaving the cloud as precipitation.
Precipitation also varies in character, what does this impact?
(Precipitation)
(The processes of the water cycle)
The water cycle at the drainage basin scale.
What happens to most rain when it reaches the ground?
(Precipitation)
(The processes of the water cycle)
It flows quickly into streams and rivers.
In high latitudes and mountainous catchments, what may happen to precipitation as it falls and reaches the ground? How does this affect the water cycle?
(Precipitation)
(The processes of the water cycle)
Often falls as snow and may remain on the ground for several months.
Thus there may be a considerable time lag between snowfall and run-off.
What is precipitation intensity?
(Precipitation)
(The processes of the water cycle)
The amount of precipitation falling in a given time.
High-intensity precipitation moves rapidly overland into streams and rivers. Why?
(Precipitation)
(The processes of the water cycle)
This is because it is falling at a rate that exceeds the infiltration capacity of the soil.
What is the average speed for high intensity precipitation?
(Precipitation)
(The processes of the water cycle)
10-15 mm/hour.
What is precipitation duration?
(Precipitation)
(The processes of the water cycle)
The length of time that a precipitation event lasts.
How can prolonged precipitation events affect the water cycle?
(Precipitation)
(The processes of the water cycle)
Prolonged events may deposit exceptional amounts of precipitation and cause saturation of the soil which leads to overland flow, and possibly river flooding.
Give an example as to how precipitation varies, and how this affect water cycles.
(Precipitation)
(The processes of the water cycle)
In some parts of the world (e.g. East Africa) precipitation is concentrated in a rainy season.
During this season river discharge is high and flooding is common.
In the dry season rivers may cease to flow together.
What is transpiration?
(Transpiration)
(The processes of the water cycle)
The diffusion of water vapour to the atmosphere from the leaf pores (stomata) of plants.
Transpiration is responsible for what percentage of moisture in the atmosphere?
(Transpiration)
(The processes of the water cycle)
Around 10%.
Transpiration is influenced by what 3 factors?
Temperature, wind speed, and water availability to plants.
Give an example of when plants try and reduce moisture loss through transpiration.
(Transpiration)
(The processes of the water cycle)
Deciduous trees shed their leaves in climates with either dry or cold seasons to reduce moisture loss through transpiration.
What is condensation?
(Condensation)
(The processes of the water cycle)
Condensation is the phase change of vapour to liquid water.
When does condensation occur?
(Condensation)
(The processes of the water cycle)
It occurs when air is cooled to its dew point.
At this critical temperature air becomes saturated with vapour resulting in condensation.
Clouds form through condensation in the atmosphere.
What are the three main types of cloud?
(Condensation)
(The processes of the water cycle)
Cumuliform clouds.
Stratiform clouds.
Cirrus clouds.
What are cumuliform clouds.
(Condensation)
(The processes of the water cycle)
Flat bases and considerable vertical development.
How do cumuliform clouds form?
(Condensation)
(The processes of the water cycle)
When air is heated locally through contact with the Earth’s surface.
This causes heated air parcels to rise freely through the atmosphere, expand, and cool.
As cooling reaches the dew point, condensation begins and clouds form.
What are stratiform clouds.
(Condensation)
(The processes of the water cycle)
Layer clouds.