KQ1- Water Cycle

Question 1

What role does water play in creating benign thermal conditions on earth? Give 3 ways

Answer 1

1. Oceans, which occupy 71% of the worlds surface store thermal energy, and slowly release it
2. Water vapour is a potent greenhouse gas, which absorbs long wave radiation, maintaining temperatures and keeping the 15(degrees Celsius) higher than they would be other wise
   3.Clouds made up of tiny water crystals, reflects about 1/5th of incoming solar radiation

Question 2

What is the use of water to flora AND fauna, give 4 ways?

Answer 2

1. Water is used for respiration, photosynthesis and transpiration (maintains rigidity)
2. In respiration, water is used to convert glucose to energy (same for fauna)
3. water makes up 65-95% of all living organisms
4. Water is a great metabolite where many chemical reactions take place as well as being used to circulate oxygen around the body

Question 3

What is the use of water to people?

Answer 3

1water is used for economic activity, generate electricity, recreation and irrigation as well as manufacturing

Question 4

Are the carbon water cycle a closed or an open system?

Answer 4

Globally, the suns energy drives the system (external to the earth), only energy can cross the boundaries of the water and carbon cycle, so its regarded as closed. But locally, e.g. drainage basin, both energy and material is able to be exchanged so they are regarded as open

Question 5

How much water is stored in the oceans?

Answer 5

97%, they dominate the global water cycle

Question 6

Where is freshwater stored and how much of it is stored in these places?

Answer 6

Tiny proportion of the worlds water is freshwater, with around 75% in the ice caps of Greenland and Antarctica, whilst 1/5th is stored below permeable rocks

Question 7

How much water is stored in the atmosphere? Provide reasoning behind this statistic

Answer 7

Only a minute fraction, despite it’s pivotal role in the water cycle (only around 0.001%), this paradox can be explained by the rapid flux of water into and out of the atmosphere, the average residence time of a water cycle is only 9 days.

Question 8

According to the USGCs estimates, the global water cycle budget circulates around … of water per year as inputs and outputs between principal water stores

Answer 8

505,000km^3

Question 9

What is the equation for the water balance? and what does it show?

Answer 9

Precipitation (P) = Evapotranspiration (E) + Stream flow (Q) +/- storgae (S)
It shows the flows of water in a drainage basin

Question 10

How does precipitation form?

Answer 10

When vapour in the atmosphere reaches its dew point, and condenses into tiny water droplets, these eventually aggregate, reach a critical size before falling as precipitation

Question 11

How does precipitation vary in high latitudes?

Answer 11

Precipitation in high latitudes such as mountain catchments fall as snow and may remain for a period of time, hence there is a lag between precipitation and run off

Question 12

How does high intensity rainfall impact the water cycle at the drainage basin level?

Answer 12

High Intensity rain fall (10-15mm/hour) moves rapidly overland as the run off into rivers and streams exceeds the infiltration capacity of the soil

Question 13

How can prolonged precipitation lead to flooding?

Answer 13

These are linked to depressions or frontal rainfall and can deposit exceptional amounts of precipitation over time to the point where saturation of soil occurs and water runs rapidly overland, leading to flooding

Question 14

How can precipitation vary across the Mediterranean and East Africa?

Answer 14

Precipitation can be concentrated in one rainy season where river discharge is high, and can lead to flooding

Question 15

What is transpiration?

Answer 15

Loss of water vapour from the stomata of a leaf

Question 16

How much moisture in the atmosphere is from transpiration?

Answer 16

10%

Question 17

Give 3 factors influencing transpiration

Answer 17

1. Temperature
2. Wind speed
3. Water availability e.g. deciduous trees shed leaves when climates are cold or dry to reduce moisture loss by transpiration

Question 18

How do clouds form?

Answer 18

By condensation -Change from vapour to liquid as air is cooled to it’s dew point

Question 19

How do cumuliform clouds form?

Answer 19

They have considerable vertical development, with flat bases and form when air is heated locally through contact with the earth, and this causes air to rise by convection, expand due to fall in pressure and the cool to it’s dew point where condensation occurs and clouds form

Question 20

How do stratiform clouds form?

Answer 20

Layer clouds, they form as air moves over a cooler surface, often ocean, together with some mixing and turbulance this process is known as advection

Question 21

Why do wispy cirrus clouds very limited impact on the water cycle?

Answer 21

They form at higher altitudes and don’t produce precipitation, so have a limited impact on the water cycle

Question 22

Condesation at or near the surface produces…

Answer 22

Dew or fog, this deposits lots of moisture onto the surface and vegetation

Question 23

What are lapse rates?

Answer 23

They describe the vertical distribution of temperature in the lower atmosphere and the temperature changes that occur in an air parcel as it rises vertically from the ground

Question 24

What is environmental lapse rate?

Answer 24

vertical temperature profile of the lower atmosphere at any given time on average it drops by 6.5C every 1km of height gained

Question 25

What is dry adiabatic lapse rate?

Answer 25

Rate at which a dry parcel of air (with no condensation happening) cools, cooling caused by adiabetic expansion is approx 10C/km

Question 26

What is saturated adiabatic lapse rate?

Answer 26

Rate at which a saturated parcel of air (one with condensation happening cools), cooling is 7C/km, lower than DALR because some energy is released as latent heat

Question 27

How is precipitation produced?

Answer 27

Develops as tiny water droplets formed by condensation in saturated air grow until they are heavy enough to fall by any moving current s beneath

Question 28

Catchment hydrology: What is evaporation and why dose it allow huge quantities of heat to be transferred globally?

Answer 28

Change from liquid to gas, main pathway by which water enters the atmosphere, the energy is used to break molecular bonds in water rather than cause a rise in temperature, instead it’s absorbed as latent heat and then released during condensation, this allows huge quantities of heat energy to be transferred globally

Question 29

Catchment hydrology: Describe the process of interception

Answer 29

1. Significant proportion of precipitation is intercepted by vegetation
2. Any moisture evaporating from leaves is known as interception loss
3. Rainfall briefly intercepted before falling to the ground is known as through fall
4. During periods of prolonged rainfall, intercepted rainwater may flow to the ground along branches as stemflow

Question 30

Describe the 4 factors affecting interception

Answer 30

1. Interception storage capacity- beofre rainfall, veg surfaces are often dry, and their abilty to reatain water is at maximum, but as they become more saturated output of water through stemflow and throughfall increases
2. Wind speed
3. Vegetation type
4. Tree species

Question 31

Describe the 4 factors affecting interception

Answer 31

1. Interception storage capacity- before rainfall, veg surfaces are often dry, and their ability to retain water is at maximum, but as they become more saturated output of water through stemflow and through fall increases
2. Wind speed- evaporation rises with wind speed, turbulence also increases leading to more through fall
3. Vegetation type-interception loss greater from grasses than crops, also higher for crops with greater surface are and aerodynamic roughness also have greater loss
4. Tree species- interception loss greater from evergreen conifers than deciduous, this is because conifers have leaves all year round with conifer needles where water can adhere to, so more evaporation

Question 32

Rainfall that doesn’t fall directly into rivers follow which other paths to streams and rivers

Answer 32

1. Infiltration by gravity into soil and then throughflow into rivers
2. over land flow across the surface

Question 33

What are 2 conflicting ideas about overland flow and when it occurs?

Answer 33

1. When intensity of rain exceeds the infiltration capacity, rain moves rapidly overland
2. This states that regardless of intensity, rain always infiltrates the soil and only flows as overland flow if the soil becomes saturated and water table rises to the surface

Question 34

What type of flow occurs where you can find permeable rock below the soil?

Answer 34

water percolates the permeable rock pores and joints, it migrates as groundwater flow and can eventually emerge as springs and seepages

Question 35

What is the pattern of groundwater levels on chalk in southern England across the year?

Answer 35

By October, levels rise due to fall in transpiration and temperatures, with recharge until late January and then it steadily declines as it reaches its lowest in early autumn

Question 36

What is ablation? Cryosphere processes

Answer 36

Loss of ice from snow, glaciers due to combo of melting, evaporation and sublimation

Question 37

Why is ablation a problem across upland britain?

Answer 37

Meltwater is a key component of river flow from snow being thawed, this can lead to flooding in adjacent lowlands of upland Britain e.g. Pennines