Lesson 3- What are flows in the water cycle and how do they change where water is stored? (Finished but may need key terms list) Flashcards
Key words-Precipitation
Transfer of water from the atmosphere to the Earth’s surface in the form of rain, hail, snow and dew
Key words-Interception
Precipitation that is caught and stored (temporarily) on its way to the surface by leaves, plants, grasses and tree
Key words-Overland/Surface Flow
This is when the water flows over the lands surface
Key words-Infiltration
Where the water enters small openings and pores in the ground from the surface
Key words-Percolation
Where water flows down through the soil
Key words-Groundwater Flow
Also calledbaseflowand is water that has infiltrated and percolated into the bedrock and below the water table
Key words-Transpiration
Where water is evaporated from plants through stomata
Key words-Evaporation
Where liquid becomes a gas as water is heated up often by solar energy.
-The air must not be saturated so it can absorb the water vapour
Key words-Evapotranspiration
Combination of evaporation and plant transpiration
Key words-Condensation
Transfer of water vapour to a liquid
Key words-Sublimation
Water changes from solid (ice) to gas (water vapour) without passing through the liquid state
Key words- Trunk and Stem flow
This is the flow of water down the stems of plants or trunks of trees
Key words- Zone of saturation
The height of the water table will vary according to the season. Where there is permanent saturation, this is called thephreatic zone
Factors affecting Evaporation
- Amount of solar energy-hotter means more evaporation
- Availability of water-more water means more evaporation
- Humidity of Air- More humid less evaporation
- Windspeed-More wind more evaporation
What is humidity?
The amount of water vapour in the air. This is very important for cloud formation
What is absolute humidity?
Amount of water vapour that air can hold. Saturated air is where air is full of water vapour, this then causes condensation to occur.
- For colder air it takes less moisture to saturate the air than for warmer air meaning warmer air can hold more water vapour
What is relative humidity?
Is the amount of water vapour can gold as a percentage.
-for saturation/ condensation to occur it much reach 100%
What is adiabatic expansion
High pressure-air particles hit each other frequently as they are packed together.
-When air heats up itexpands, this causes the particles to be further apart and therefore the pressure to decrease. The lower pressure means the particlescollide less.
- Thereforeheat transfer is notgoing to happen as much, thiscauses the temperature to godown.(adiabatic cooling)
What are lapse rates
- With increased altitude temperature drops.
- Ifan air parcel is warmer than
surroundingairwe get absolute instability. - This means itcontinues to rise.
- Air rises until it is stable and reaches the sametemperatureasthesurrounding
atmosphere. - At this point you get absolute stability and the air won’t rise any more.
What are environmental lapse rates
- 6.5 degrees drop in temp for every 1000m altitude
What are Dry Adiabatic Lapse Rates
- for unsaturated air (air not full of water), cools at 10 degrees for every1000minheight.
- Dry air cools at a different rate to saturated air.
What is the dew point?
Where air is saturated. (Full of water 100% humidity)
What is the saturated adiabatic lapse rate?
- For saturated air, condensation is takingplaceandcoolingoccurs at 7 degrees for every 1000m.
- This rate is slower
- Ascondensationreleasesheat intothe atmosphere warming it up. This keeps the airwarmer than it shouldbe.
How do clouds form?
-Sun gives off solar radiation which heats the ground or sea, this ground heats the air directly in contact with it through conduction.
- Then because air is less dense as it is warmer it rises, expands and cools
What are the types of cloud formation?
- Convection
- Orographic
- Advectional
- Frontal
Types of cloud formation- Convection
- To get convective clouds we just need a warm surface.
- This often happens in summer as there ismore solar radiation warming up the ground causing the initial uplift of air for convection.
Types of cloud formation-Orographic
- This is where air is forced to rise over hills/mountains.
- This causes the adiabatic expansion of air,causing condensation and therefore clouds to form.
- This then causes air to sink the other side ofthe hills through adiabatic warming and therefore it makes it dry the other side and creates a rainshadow.
Types of cloud formation- Advectional
- Another way we can get clouds is advection.
- This is where warm air moves horizontally over acooler surface causing it to reach its dew point and therefore condensing into clouds – oftenlowlevelclouds = fog
Types of cloud formation- Frontal
- Two air masses meet each other (one warm one cold) theycantmix so one goes over the other.
- This causes rising air and condensation and therefore cloud formation.
- This happens around theUK.
How does cloud formation vary spatially?
1) The Equator receives moreinsolation, resulting in highertemperatures which cause high ratesof evaporation
2)As the warm, moist air rises, it cools,condenses and forms banks oftowering clouds with heavy rainfall
3)This area is a low-pressure zoneknown as theInter-TropicalConvergence Zone (ITCZ)
4)The ITCZ (also called the ‘thermalequator’) tracks with the seasonalmovement of the Sun, north andsouth of the equator bringing
5)Thisshows temporal and spatialchanges in stores and transfers on aglobal basis
Inputs into water cycle
Precipitation:
- Convectional
- Relief
- Frontal
Outputs of the water cycle
- Evapotranspiration
- Evaporation
- Transpiration
- Streamflow
Flows within the water cycle
- Infiltration
- Percolation
- Through flow
- Surface runoff
- Groundwaterflow
- Streamflow
- Stemflow
Stores within the water cycle
- Soil water
- Ground water
- River channel
- Interception
- Surface store
- Water table
