Water & Carbon Flashcards
(32 cards)
1.1 SYSTEMS IN PHYSICAL GEOGRAPHY
What is a system?
A system is all the components in an ecosystem/area and the relationships or links (flows/tranfers) between them
1.1 SYSTEMS IN PHYSICAL GEOGRAPHY
What is an input, output, transfer/flow, store/sink in a system?
input: material/energy moving into the system from outside
output: material or energy moving from the system to the outside
transfer/flow: the links/relationships between the components
store/sink: the individual elements/parts of a system
1.1 SYSTEMS IN PHYSICAL GEOGRAPHY
What is meant by the concept of dynamic equilibrium? Give an example
a state of balance within a constantly changing system (often equal rates of inputs and outputs)
e.g.) remote and unaffected drainage basin/woodland where there has been no significant natural or hyman impacts, or one that has had time to adjust to change
1.1 SYSTEMS IN PHYSICAL GEOGRAPHY
What is an open system? Give an example
a system with inputs and outputs to other systems
e.g.) drainage basin or a forest
1.1 SYSTEMS IN PHYSICAL GEOGRAPHY
What is a closed system? Give an example
a system wih no inputs or outputs
e.g.) the global water system or the global carbon system
1.1 SYSTEMS IN PHYSICAL GEOGRAPHY
How does the water cycle operate as both an open and closed system at different scales?
at a local scale, a drainage basin operates as an open system
- precipitation as an input and runoff to the oceans as an output.
- stores: trees, built-up areas and soils
- flows and transfers: throughflow and groundwater flow
at a global scale, the global water cycle is a closed system
- water is not lost to or gained from space
1.1 SYSTEMS IN PHYSICAL GEOGRAPHY
What is positive feedback?
a cyclical sequence of events that amplifies or increases change. positive feedback loops exacerbate the outputs of a system, driving it in one direction and promoting envronmental instability (i.e. pushes it further away from a state of dynamic equilibrium)
1.1 SYSTEMS IN PHYSICAL GEOGRAPHY
What is negative feedback?
a cyclical sequence of events that damps down or neutralises the effects of a system, promoting stability and a state of dynamic equilibrium
1.1 SYSTEMS IN PHYSICAL GEOGRAPHY
Give an example of positive feedback in the water cycle
deforestation > fewer trees to intercept precipitation > less evapotranspiration and infiltration > less water in atmosphere to be condensed into clouds > fewer clouds > less precipitation > system brought further from its state of dynamic equlibrium
1.1 SYSTEMS IN PHYSICAL GEOGRAPHY
Give an example of negative feedback in the water cycle
Earth warms > increased evaporation from the oceans > more water vapour in atmosphere > more cloud formation > white clouds reflect sun’s energy as they have a high albedo > temps reduce > Earth cools
1.2 THE GLOBAL WATER CYCLE
What is the water cycle? Outline the 4 main stores of the global water cycle
water cycle: the path that all water follows as it moves around the earth system in different states
lithosphere - all the rock on earth
hydrosphere - all the water on earth
cryosphere - all the ice on earth
atmosphere - the air
1.2 THE GLOBAL WATER CYCLE
What proportion of water is in each of the major stores?
2.5% of the earth’s water is freshwater
70% of the earth’s freshwater is stored in the cryosphere (glaciers, ice caps, ice sheets), 30% in groundwater
1.2 THE GLOBAL WATER CYCLE
What are ground aquifers? Give an example of a major aquifer system
Aquifer: a body of rock and/or sediment that holds groundwater
e.g.) NW Sahara aquifer system and the Nubian sandstone aquifer system (both in northern Africa)
1.3 CHANGES IN THE MAGNITUDE OF THE WATER CYCLE STORES
What are the typical residence times of water in each one of the main stores?
Soil water: 1-2 months
Rivers: 2-6 months
Seasonal snow cover: 2-6 months
Glaciers: 20-100yrs
Lakes: 50-100yrs
Shallow groundwater: 100-200yrs
Deep groundwater: 10,000 yrs
1.3 CHANGES IN THE MAGNITUDE OF THE WATER CYCLE STORES
What are the 10 main processes of change (transfers) in the water cycle?
Evaporation
Transpiration
Condensation
Interception
Infiltration
Throughflow
Percolation
Groundwater flow
Surface runoff/overland flow
Channel flow (in rivers)
1.3 CHANGES IN THE MAGNITUDE OF THE WATER CYCLE STORES
What is meant by the infiltration rate in soil? Which stores does it connect?
infiltration rate: the rate in which water moves into the soil layer from the surface
–> connects surface storage with soil moisture storage
1.3 CHANGES IN THE MAGNITUDE OF THE WATER CYCLE STORES
What is the difference between infiltration and percolation?
infiltration: water moving into soil layer
percolation: water moving into rock layer
1.3 CHANGES IN THE MAGNITUDE OF THE WATER CYCLE STORES
What impact do glacial and inter-glacial periods have on the water cycle? 3 facts
- glaciers and ice sheets store nearly 70% of the world’s fresh water and would raise the sea level by 70m if they melted
- at the last glacial maximum (21,000yrs ago), glacial cover caused sea level to be 115-130m lower than at present
- Ice age: expansion of ice sheets > high albedo > more reflection of sun rays > cooler climate
1.3 CHANGES IN THE MAGNITUDE OF THE WATER CYCLE STORES
What is the inter-tropical convergence zone (ITCZ)? Where would you find it?
- band of low pressure around the earth, lies near the equator
- trade winds of northern and southern hemisphere come together here => development of frequent thunderstorms and heavy rain
1.3 CHANGES IN THE MAGNITUDE OF THE WATER CYCLE STORES
Which processes of change (transfers/flows/changes in storage) can happen in short timescales and which ones happen over longer timescales?
short - diurnal changes (day and night) in evaporation, interception after a rain storm
longer - glaciers/ice sheets can lock up ice for millions of years, percolation of water into aquifer systems can remain there for 1000s of years
1.3 CHANGES IN THE MAGNITUDE OF THE WATER CYCLE STORES
What are the 4 physical factors driving change in the water cycle?
CHECK LESSON NOTES ON THIS !!
storm events: large quantities of precipitation over a short period of time can lead to steep rising limb on storm hydrographs (e.g. Hurricane Sandy)
seasonal changes in rainfall patterns: most of UK sees higher rainfall totals in winter, however there are more intense storms in summer
seasonal floods (e.g. monsoon season in Odisha, India) and seasonal snowmelt (winter snowfall and spring snowmelt) provide more than 1/2 of the annual freshwater needs of around 700 million people in South Asia (Himalayas)
medium term variations: e.g.) El Nino: causes an area of warmer water to move from west to east Pacific, resulting in higher rainfall than usual in east Pacific (S America) region, and it’s therefore drier in west Pacific (Indonesia)
1.3 CHANGES IN THE MAGNITUDE OF THE WATER CYCLE STORES
What are the 3 human factors driving change in the water cycle?
Farming:
- seasonal variations of crop cover in UK => varying interception rates based on crop coverage
- e.g.) Exmoor peat bog drainage for farming, especially over last 200 years, now rewetting the bog
- e.g.) slash and burn to create farmland for palm oil plantations in Indonesia
Land use change:
- e.g.) deforestation in Indonesia and Amazon => impact on rainfall patterns
- e.g.) urbanisation of Solihull results in increased runoff and shorter lag times for the river Blythe
Water abstraction:
- e.g.) London uses an aquifer for its water supply, which is vulnerable to over-abstraction as the population (and therefore water usage) grows
- e.g.) Saharan aquifer used for agriculture (potato farming in Egypt)
1.3 CHANGES IN THE MAGNITUDE OF THE WATER CYCLE STORES
Give 3 examples of how farming can impact the water cycle.
- drainage ditches - drain water from farmland and so increases rate of overland flow, reduces rate of infiltration
- crop type - some crops have higher interception rates than others
- deforestation to clear land for farming - less trees means reduced rate of interception and infiltration and increased rate of overland flow
1.4 THE DRAINAGE BASIN SYSTEM
What is a drainage basin? Which one is Alderbrook School in?
- drainage basin - an area of land that gathers all the precipitation that drains into one river system
- ABK is part of the River Blythe drainage basin
