OCR A Level ELSS - Entire Course 3

Question 1

Cryospheric processes

Answer 1

-ablation is loss of ice from snow, ice sheets and glaciers due to a combination of melting, evaporation and sublimation
-meltwater is an important component of river flow in high latitudes and mountain catchments in spring and summer
-rapid thawing of snow in winter is a common cause of flooding in adjacent lowlands

Question 2

physical (inorganic) pump?

Answer 2

-involves mixing of surface and deep ocean waters by vertical currents
-creates a more even distribution of carbon in oceans
-CO2 diffuses into the oceans from atmosphere
-surface currents transport dissolved CO2 polewards where it becomes dense and sinks (downwelling)
-individual carbon particles may remain deep in the ocean for many centuries
-eventually deep ocean currents transport carbon back up to the surface (upwelling)
-cold, carbon rich waters rise to the surface where CO2 diffuses back into the atmosphere

Question 3

biological (organic) pump?

Answer 3

-50% of carbon fixation happens by photosynthesis in oceans
-50GT of carbon is drawn from atmosphere by biological pump each year
-marine organisms (phytoplankton) drive the pump
-phytoplankton floating near surface combine sunlight, water and CO2 into organic material
-whether consumed in the food chain or through natural death, carbon locked in phytoplankton accumulates on the ocean floor or is decomposed and released as CO2. or is used by organisms for shells and skeletons
-most CO2 ends up in sediments such as chalk and limestone

Question 4

What is permafrost?

Answer 4

a thick subsurface layer of soil that remains frozen throughout the year, occurring chiefly in polar regions.

Question 5

what is the active layer?

Answer 5

-The top layer of permafrost.
-melts

Question 6

water cycle negative feedback loop

Answer 6

heavy rainfall = increased water infiltration = more water stored in aquifers = water table is raised = more water is returned to the surface as springs = water table returns to normal levels

Question 7

carbon cycle negative feedback loop

Answer 7

burning of fossil fuels = increased atmospheric CO2 = photosynthesis stimulated = more CO2 removed form the atmosphere = CO2 levels restored

Question 8

3 land use changes?

Answer 8

1. urbanisation
2. farming
3. forestry

Question 9

land use changes - urbanisation?

Answer 9

-farmland and woodland areas replaced by tarmac and brick
-artifical surfaces are impermeable and allow little water infiltration and provide minimal water storage capacity, giving rise to run off
-urban areas have drainage systems designed to remove water rapidly (gutters, pitched roofs) therefore water form precipitation flows quickly into streams and rivers, leading to a rapid rise in the water tables
-urbanisation also encroaches floodplains which are natural water stores
-overall, urbanisation reduces water storage capacity in drainage basins, increasing river flow and flood risks

Question 10

land use changes - farming and the carbon cycle?

Answer 10

-clearance of forest for farming reduces carbon storage in above and below ground biomass
-soil carbon storage is reduced by ploughing and exposure of organic material to oxidation
-harvesting of crops returns only a small amount of organic matter to the soil
-soil erosion by wind and soil is most severe when crops have been lifted and have little protective cover
-carbon exchanges through photosynthesis are lower due to a lack of biodiversity and a short growth cycle

Question 11

land use changes - farming and the water cycle?

Answer 11

-crop irrigation diverts surface water from rivers and groundwater to cultivated land
-interception of crops is less than of grasslands,
-evapotranspiration is reduced by crops
-ploughing increases evaporation and soil moisture loss
-heavy machinery compacts the soil which leads to more surface run off leading to peak flows higher in farmland ecosystems
-ploughing causes infiltration which means even more water is transferred to streams and rivers

Question 12

land use changes - forestry plantations and the water cycle?

Answer 12

-there is a higher rate of rainfall interception in natural plantations
-preferred plantation species in the uk are conifers with needle like structures, evergreen habit and high density
-increased evaporation form water stored on leaf surfaces
-reduced run off and stream discharge due to high interception and transpiration rates
-clear felling of harvest timber creates a sudden change in the water cycle, increasing run off, reducing evapotranspiration and increasing stream discharge

Question 13

land use changes - forestry plantations and the carbon cycle?

Answer 13

-in the uk a typical plantation contains 10x more carbon than grassland and 20x higher than heathland
-soil represents a large carbon pool - 500 tonnes/ha
-forest trees extract carbon for hundreds or years only after 100 years since planting
-balanced by litter inputs into the soil

Question 14

what were the CO2 levels in the atmosphere 800,000 years ago compared to today (2016)?

Answer 14

-260 ppm 800,000 years ago
-400.5 ppm 2016
-small changes over 800,000 years due to glacials and interglacials

Question 15

what were the CO2 levels in the atmosphere in 1700 compared to 2016?

Answer 15

-most people lived in rural areas in 1700
-1800 - the industrial revolution and CO2 levels rapidly increased due to coal use
-1910 - the first production line car
-1913 - coal extraction
-1960 - increase in car use and central heating fitted in homes
-1700 - 310 ppm
-2016 - 400.5 ppm

Question 16

changes in the CO2 levels in the past two years?

Answer 16

-400.5 ppm
-in spring and summer there is less CO2 in the atmosphere due to more vegetation therefore increased photosynthesis
-in winter there is increases in CO2 due to more use of heating inn homes
-increased in 5 ppm in two years

Question 17

energy consumption overtime?

Answer 17

-oil (496 GT) and coal (673 GT) are the largest carbon emission sources
-coal has been used since the industrial revolution and oil has been used since 1920s
-since 1970s there has been an increase in use of nuclear and hydroelectric sources
-overall global energy consumption has increased rapidly since the 1960s with coal and oil being the main sources

Question 18

3 stages involved in CCS?

Answer 18

1. separate CO2 from power station emissions
2. CO2 is compressed and transported to storage areas
   3.injected into porous rock underground and stored permanently

Question 19

what is the impact and plans of CCS?

Answer 19

-plays an important role in reducing CO2 and other emissions
-in USA, 40% of all carbon emissions could be reduced by 80-90%
-in the UK a CCS project is underway in peterhead, north east Scotland which is going to capture 2 million tonnes of CO2
-plan for carbon to be transported by pipeline to the North Sea and stored in depleted gas resevoirs

Question 20

Why is the CCS limited?

Answer 20

-involves big capital costs
-uses large amounts of energy (compress and transport CO2)
-requires storage in specific geological locations

Question 21

in 2013 what percentage did fossil fuels account for the overall energy consumption?

Answer 21

87% fossil fuels

Question 22

what sources were used the most in 2013 for global energy consumption?

Answer 22

-oil (37%)
-natural gas (27%)
-coal (23%)

Question 23

where have most of our carbon emissions come from (1750 - 2012)?

Answer 23

-coal - 673GT
-land use - 590GT

Question 24

where have our carbon emissions gone (1750 - 2012)?

Answer 24

-atmosphere (879GT)
-ocean (590GT)
-land (528GT)

Question 25

how many tonnes of CO2 is released into the atmosphere annually?

Answer 25

-10 billion tonnes -increases the CO2 concentration over 1 ppm

Question 26

impact of anthropogenic carbon emissions in the atmosphere?

Answer 26

-since 1750, 879GT of anthropogenic co2 emissions have remained in the atmosphere, tasing co2 concentrations from 280 ppm - 400 ppm -co2 levels today have been the highest for 800,000 years

Question 27

what is the impact of anthropogenic carbon emissions?

Answer 27

-compromise only 10% of the natural influx of from the biosphere, oceans and atmosphere -however they impact significantly on carbon stores -despite international efforts used to reduce carbon emissions, between 2000 and 2009 they grew faster than in any other decade -without increased absorbtion of CO2 from oceans and biosphere, atmospheric concentrations would exceed 500 ppm

Question 28

groundwater

Answer 28

water stored underground in permeable and porous rocks know as aquifers

Question 29

aquifer

Answer 29

a water bearing band of porous or permeable rock

Question 30

artesian aquifer

Answer 30

a confined aquifer containing groundwater under pressure, which will rise to the surface under its own pressure

Question 31

artesian pressure

Answer 31

The hydrostatic pressure exerted on groundwater in a confined aquifer occupying a synclinal structure.

Question 32

abstraction

Answer 32

the extraction of water from rivers and boreholes for public demand

Question 33

impact of water extraction?

Answer 33

-rates of extraction have exceeded rates of discharge -lower flows have reduced flood risk and temporary areas of standing water on floodplains -lower groundwater levels ave caused springs to dry up and reduce the instance of saturated overground flow on chalk

Question 34

the water table?

Answer 34

-the level below which the ground is saturated with water.

Question 35

changes that occur in the water table levels?

Answer 35

-water table heights fluctuate seasonally by periods of lots of rainfall, drought and abstraction -in normal years in southern England, the water table falls between march and September due to rising temperatures and increased evapotranspiration -recharge resumes in late autumn

Question 36

artesian basins

Answer 36

-when sedimentary rock forms a syncline, a downloaded basin like geological structure -confined between layers of impermeable rock (clay) -may contain groundwater under artesian pressure -when groundwater is tapped by a well or borehole water will flow to its surface under its own pressure

Question 37

what is remote sensing?

Answer 37

the scanning of the earth by satellite or high-flying aircraft in order to obtain information about it.

Question 38

what is GIS?

Answer 38

-Geographic Information System. -A computer that can capture, store, query, analyze, and display geographic data. -analyses layers, spacial location and identifies any anomalies and trends

Question 39

what are diurnal changes?

Answer 39

-significant changes that occur within a 24 hour period -lower temperatures at night reduce evaporation and transpiration -during the day convectional precipitation is dependent on direct heating of ground surface by the sun -flows of carbon are reversed at night compared to day

Question 40

what are seasonal changes?

Answer 40

-seasons are controlled by the variations in solar radiation -in uk, solar radiation peaks in mid June (800 w/m2) in southern england -compared to input of (150 w/m2) in December -80% of precipitation is lost to evaporation in driest parts of lowland England, which exhausts soil moisture and river flows are lowest in late summer

Question 41

how are seasonal changes reflected in the carbon cycle?

Answer 41

-month-month changes in the net primary productivity (NPP) -in middle and high latitudes day length of photoperiod drive seasonal changes in NPP -similar variations occur in tropics, but there main cause is water availability

Question 42

carbon dioxide flows in the summer?

Answer 42

-net flow of CO2 from atmosphere to biosphere -causes CO2 levels to fall by 2ppm -at end of summer flow is reversed by natural decomposition releasing CO2 back to atmosphere

Question 43

what are seasonal fluctuations in global CO2 flux explained by?

Answer 43

-concentration of continental land masses in the northern hemisphere -during growing season, ecosystems such as boreal and forests extract huge amounts of CO2 from atmosphere which has a huge global impact

Question 44

what happens during seasonal changes to phytoplankton in the oceans?

Answer 44

-in oceans phytoplankton are stimulated to photosynthesise by rising water temperatures, more intense sunlight and the lengthening photoperiod -in northern Atlantic, ever year there is an explosion of microscopic ocean activity, resulting in algal blooms which peak in mid summer

Question 45

impact of long term changes - how many major glacial cycles in the last 400,000 years?

Answer 45

-4 major glacial cycles in the last 400,000 years -each last around 100,000 Years -followed by warmer interglacials

Question 46

temperatures at the height of the last glacial?

Answer 46

-20,000 years ago -temperatures on average 5 degrees lower than they are today at the peak of the last glacial

Question 47

what happened during the last glacial to most of the UK?

Answer 47

-scotland, Wales and Northern Ireland were submerged in ice up to 1km thick

Question 48

impact on water cycle during glacial periods (sea level and sea ice)?

Answer 48

-in glacials sea level falls by 100-130m -ice sheets expand over one third of the continental land mass -ice sheets destroy forests and grasslands as they expand towards the equator -lower rates of evapotranspiration reduces flows of water in the cycle -overall water cycle decreases

Question 49

impact on carbon cycle during glacial periods (temperature and CO2 concentration, oceans and phytoplankton ) ?

Answer 49

-dramatic reduction in CO2 in atmposphere -glacial maxima concentrations fall to 180 ppm -warmer interglacials they were 100 ppm higher -close correlation between temperature and CO2 concentration -more CO2 dissolves in oceans at lower SST as lower temperatures make the sea more soluble -ocean circulation brings nutrients to the surface and stimulates phytoplankton growth -overall a slowing carbon flux and smaller amounts of CO2 returned to atmosphere by decomposition

Question 50

how are carbon and water cycles linked by the atmosphere?

Answer 50

-atmospheric CO2 has a greenhouse effect -CO2 plays role in photosynthesis for plants and phytoplankton -plants extract water from soil and transpire it to the atmosphere -water is evaporated from the oceans to the atmosphere which causes CO2 to be transferred between both stores

Question 51

how are carbon and water cycles linked by the ocean?

Answer 51

-ocean acidity increases when CO2 stores are unbalanced -solubility of CO2 increases with lower SST -CO2 levels influence SST, thermal expansion, air temperatures, melting of ice and sea level

Question 52

how are carbon and water cycles linked by vegetation and soils?

Answer 52

-water availability influences photosynthesis, NPP, inputs of organic material and transpiration -increased inputs of organic material to the soil increases the soils water storing capacity -temperatures and rainfall affects decomposition and release of CO2

Question 53

how are carbon and water cycles linked by cryosphere?

Answer 53

-CO2 levels determine the intensity of the greenhouse effect and melting of ice sheets, glacials and sea ice -melting of ice exposes land which increases the absorption of solar radiation which increases temperatures -melting of permafrost exposes dead organic material to decomposition and oxidation -run off, river flow and evaporation respond to temperature change

Question 54

what 4 anthropogenic factors have impacted the water and carbon cycles?

Answer 54

-urbanisation -rapid population change -deforestation -economic change =they have changed the size of stores and impacted most at local and regional scales

Question 55

what has created shortages in the water cycle?

Answer 55

-rising demand for water for agriculture, irrigation and public supply -human impact most evident on rivers and aquifers

Question 56

what effect do anthropogenic factors have on the water cycle?

Answer 56

-decrease through flow -lower water tables -increase run off -reduce evaporation and precipitation

Question 57

where have human activities had a detrimental impact on the water cycle - examples?

Answer 57

-colorado basin, southwest USA -surface supplies diminished as more water extracted from rivers -huge amount evaporated from reservoirs in Lake mead and Powell -bangladesh -excessive water pumping of aquifers led to inclursions of salt water which makes the water unfit for drinking and irrigation

Question 58

what are the impacts of deforestation?

Answer 58

-impact areas like Amazonia as forest trees play a huge role in the water cycle -deforestation has decreased evapotranspiration therefore precipitation, breaking the cycle in some places which stops forest regeneration

Question 59

how is human actives impacting the carbon cycle? (3)

Answer 59

-extracted billions of tonnes of carbon from the geological store -the world relies on fossil fuels for 87% of the worlds total energy consumption -land use changes, deforestation transfers 1 billion tonnes of carbon to atmosphere annually -more CO2 absorbed by oceans due to more CO2 in atmosphere -increases ocean acidity which kills phytoplankton -soil degraded by erosion caused by deforestation and agricultural mismanagement

Question 60

why has exploitations of coal, oil and gas stores increased rapidly recently?

Answer 60

exploitations of coal, oil and gas has increased rapidly due to the increasing industrialisation in India and china

Question 61

Carbon cycle: burning fossil fuels transfers ____________________ of carbon to the atmosphere

Answer 61

8 billion tonnes

Question 62

Carbon cycle: land use changes (deforestation) transfers ____________________ carbon to the atmosphere

Answer 62

1 billion tonnes

Question 63

Carbon cycle: ocean acidification

Answer 63

-Ocean acidity increases when exchanges of CO2 aren't in balance -more CO2 dissolves into oceans when more co2 is in the atmosphere -acidification kills phytoplankton

Question 64

Carbon cycle: soil is degraded by erosion caused by what? (2)

Answer 64

deforestation and agricultural mismanagement

Question 65

Carbon cycle: why are carbon stores in wetlands depleted?

Answer 65

When the wetlands are drained for cultivation and urban development they dry out and are oxidised

Question 66

global warming leads to increased ----- in the atmosphere?

Answer 66

leads to increased water vapour in the atmosphere

Question 67

impact of long term changes on the water cycle?

Answer 67

-more water vapour in the atmosphere is a natural GHG -vapour releases heat when it evaporates, cools and condenses which increases frequency of tropical storms -global warming also accelerates melting of glaciers which transfers water from cryosphere to oceans + atmosphere

Question 68

What does water release as it evaporates, cools and condenses?

Answer 68

heat

Question 69

What could global warming increase the prevalence of and why?

Answer 69

hurricanes as they rely on warmer water

Question 70

long term impacts of climate change on the carbon cycle - What does global warming lead to?

Answer 70

-higher temperatures increases rate of decomposition -therefore accelerates flows of carbon from biosphere to atmosphere -carbon stored in permafrost released to atmosphere -acidification of oceans due to excess co2 in atmosphere kills phytoplankton, reducing rate of photosynthesis which limits oceans capacity of storing carbon

Question 71

what changes occurs in stores of carbon due to long term impacts of climate change?

Answer 71

-less carbon stored in biosphere and ocean stores -more carbon stored in the atmosphere

Question 72

why is more carbon released to the atmosphere because of global warming? (2)

Answer 72

-higher decomposition rates -melting of permafrost

Question 73

Negative Feedback

Answer 73

A cycle that returns a system back to its normal (equilibrium) state

Question 74

Positive Feedback

Answer 74

A 'runaway' system loop where the system moves further and further from equilibrium

Question 75

Dynamic Equilibrium

Answer 75

The steady, balanced state of a system

Question 76

Aquifer

Answer 76

Underground rock which can store and transmit water in sufficient quantities to extract for our benefits

Question 77

Artesian Basin

Answer 77

Pressurised groundwater found where permeable rock is overlain by impermeable rock, trapping water below, which entered at higher elevation

Question 78

Diurnal

Answer 78

Changes in the temperature between day and night - warmer during the day, and coolest during the night.

Question 79

Seasonal Change

Answer 79

Alteration of the weather, temperature and precipitation throughout the year, as a result of the Earth's tilt.

Question 80

Long Term

Answer 80

Time period spanning millions of years, for example.

Question 81

Cryosphere

Answer 81

The ice which exists upon Earth

Question 82

Vegetation

Answer 82

Plant life at the Earth's surface

Question 83

Climate Change

Answer 83

Alteration to long-term weather patterns, e.g. increased temperature and rainfall shifts occur naturally, but can be influenced by human activity

Question 84

Atmosphere

Answer 84

The gaseous part of the Earth - ranging from the troposphere at ground level, to the exosphere, as far as 10,000km away.

Question 85

Regulation

Answer 85

Keeping a natural system in check - for example, trees and oceans absorb carbon from the atmosphere, reducing the degree of warming to the planet.

Question 86

Management Strategy

Answer 86

Set of rules and regulations governing the use of and protection of the natural world

Question 87

Wetland Restoration

Answer 87

The reprovision of aquatic habitats - for example, in areas that were drained centuries ago for farming.

Question 88

Carbon Trading

Answer 88

Countries are allocated rights to emit certain gases - if they produce too much, they can buy credits from countries producing less than their quotas.

Question 89

International Agreements

Answer 89

Legally binding or voluntary set of rules that countries ratify across the globe, such as the Kyoto Protocol, or the Copenhagen Accord.

Question 90

Drainage Basin Planning

Answer 90

Overarching control and strategies which oversee a catchment - to reduce flooding and ensure a variety of habitats, for example.

Question 91

photosynthesis

Answer 91

process by which green plants convert water and CO₂ into starch and sugar in the presence of sunlight

Question 92

respiration

Answer 92

the process in living organisms where the intake of oxygen oxidises organic substances to produce energy and release CO₂

Question 93

transpiration

Answer 93

the evaporation of moisture from the pores on the leaf surfaces of plants

Question 94

atmosphere

Answer 94

the thin envelope of gasses (mainly Nitrogen and Oxygen) that surrounds the earth

Question 95

biosphere

Answer 95

the space at the Earth's surface and within the atmosphere occupied by living organisms

Question 96

precipitation

Answer 96

moisture (rain, snow, hail) falling from clouds towards the ground

Question 97

evapotranspiration

Answer 97

combined loss of water at the surface through evaporation and transpiration by plants

Question 98

run-off

Answer 98

the movement of water across the land surface

Question 99

groundwater flow

Answer 99

the horizontal movement of water within aquifers

Question 100

closed system

Answer 100

a system with inputs and outputs of energy, but without any movements of materials across system boundaries

Question 101

open system

Answer 101

a type of system whose boundaries are open to both inputs and outputs of energy and matter

Question 102

water reservoir

Answer 102

an area on the surface or within the ground where water is stored

Question 103

atmopspheric water store

Answer 103

the total water stored in the atmosphere

Question 104

land water store

Answer 104

the total water stored on land

Question 105

ocean water store

Answer 105

the total water stored in the oceans

Question 106

water flow

Answer 106

the movement of water between different stores

Question 107

oxidation

Answer 107

a chemical process that weathers certain types of rock and involes the absorption of oxygen from either the atmosphere or water by rock minerals.

Question 108

decomposition

Answer 108

the breakdown of a material into chemically altered forms

Question 109

combustion

Answer 109

A rapid reaction between oxygen and fuel that results in fire

Question 110

weathering

Answer 110

the decomposition or disintegration of material in situ

Question 111

system

Answer 111

A group of interacting, interrelated, or interdependent elements or parts that function together as a whole

Question 112

permeable rock

Answer 112

a type of rock that is penetrated by water, either through mineral pores (air spaces) or along joints, faults or fissures

Question 113

water cycle budget

Answer 113

the annual volume of movement of water by precipitation, evapotranspiration, run-off etc. between stores such as oceans, permeable rocks, ice sheets, vegetation, soil, etc.

Question 114

condensation

Answer 114

the phase change of water vapour (gas) to water (liquid)

Question 115

sublimation

Answer 115

the phase change of water from ice to vapour

Question 116

infiltration

Answer 116

the vertical movement of rainwater into and through the soil

Question 117

aquifer

Answer 117

a water-bearing band or porous or permeable rock

Question 118

groundwater

Answer 118

water stored underground in permeable and porous rocks known as aquifers

Question 119

sink

Answer 119

anything that absorbs more of a particular substance than it releases, e.g. the oceans act as a sink for CO₂

Question 120

carbonate rocks

Answer 120

rocks comprising carbonate materials (e.g. CaCO₃) such as limestone and chalk

Question 121

slow carbon cycle

Answer 121

the slow movement of carbon between the atmosphere and rocks, sea floor sediments and fossil fuels over millions of years. Accounts for between 10 and 100 million tonnes per year

Question 122

residence times

Answer 122

the length of time that a molecule of water or CO₂ etc. remains in natural storage (e.g. in the atmosphere or oceans)

Question 123

subducted

Answer 123

the tectonic process found at convergent plate marigins where an oceanic plate descends into the Earth's mantle and is destroyed

Question 124

upper mantle

Answer 124

the layer of the Earth's interior extending 75-200km below the surface (also known as the asthenosphere) The upper mantle is able to flow under pressure

Question 125

sedimentary rock

Answer 125

A type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together

Question 126

tectonic plate boundary

Answer 126

active area in which tectonic plate can be subducted into the upper mantle before being vented into the atmosphere via a volcano

Question 127

chemical weathering

Answer 127

the in situ breakdown (decomposition) of rocks by chemical processes such as oxidation, solution and hydrolysis

Question 128

carbonaceous rocks

Answer 128

rocks mainly comprising the fossilised remains of plants, e.g. coal, lignite.

Question 129

fast carbon cycle

Answer 129

the rapid movement of carbon between the atmosphere, oceans, biosphere and soils

Question 130

phytoplankton

Answer 130

tiny photosynthesising marine organisms in the surface waters of the oceans

Question 131

natural sequestration

Answer 131

natural process by which carbon is captured and stored

Question 132

Goldilocks zone

Answer 132

A place in the universe where conditions are right that liquid water can exist and humans could live.

Question 133

water balance

Answer 133

the relationship between precipitation, streamflow, evapotranspiration and soil moisture and groundwater storage in a drainage basin over a year

Question 134

dew point

Answer 134

the critical temperature at which condensation occurs

Question 135

catchment

Answer 135

the area drained by a river and it's tributaries i.e. a drainage basin

Question 136

intensity

Answer 136

the amount of rainfall which falls in a given time

Question 137

duration

Answer 137

the length of time something lasts

Question 138

channel precipitation

Answer 138

rain which falls directly into the river channel

Question 139

interception

Answer 139

the process by which water is stored temporarily on leaves stems and branches of vegetation

Question 140

stemflow

Answer 140

the flow of water along the branches and stems of trees and other plants to the ground

Question 141

overland flow

Answer 141

rainfall that runs off the ground surface either because the soil is saturated or the intensity of the rainfall exceeds the soil's infiltration capacity

Question 142

throughflow

Answer 142

water flowing horizontally through the soil to stream and river channels

Question 143

base flow

Answer 143

water input to streams and rivers from natural resevoirs such as aquifers, peat bogs and soils

Question 144

recharge

Answer 144

net input of water into an aquifer causing a rise in the water table

Question 145

percolation

Answer 145

the movement of surface and soil water into underlying permeable rocks

Question 146

capillary rise

Answer 146

The ability of a liquid to flow against gravity in narrow spaces, allowing water to transfer from groundwater up into soil moisture storage

Question 147

evaporation

Answer 147

the phase change of water from liquid to gas

Question 148

leakage

Answer 148

an output from groundwater stores within a drainage basin

Question 149

river discharge

Answer 149

The volume of water that flows past a point in a river per second measured in cumecs (cubic metres per second)

Question 150

cumuliform cloud

Answer 150

a cloud formed by convection with a rounded-top, lumpy appearance and flat base

Question 151

stratiform cloud

Answer 151

clouds lying in a level sheet

Question 152

advection

Answer 152

the horizontal movement of an air mass which often results in either heating or cooling

Question 153

cirrus cloud

Answer 153

a high altitude, feather-like cloud made of ice crystals

Question 154

dew

Answer 154

deposits of moisture on the ground and vegetation due to condensation caused by radiative cooling, most often at night

Question 155

fog

Answer 155

cloud at ground level caused by radiative cooling and advection

Question 156

adiabatic expansion

Answer 156

the expansion of a parcel of air due to a decrease in pressure. Expansion causes cooling

Question 157

convection

Answer 157

the motion of a gas or liquid which when warmed rises until eventually it cools and sinks in a continuous circulation

Question 158

lapse rate

Answer 158

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

Question 159

environmental lapse rate

Answer 159

the vertical temperature profile of the lower atmosphere at any given time. On average the temperature falls by 6.5°C for every km of height gained

Question 160

dry adiabatic lapse rate

Answer 160

the rate at which a parcel of dry air (i.e. less than 100% humidity so that condensation is not taking place) cools as it rises through the atmosphere. Approximately 10°C/km

Question 161

saturated adiabatic lapse rate

Answer 161

the rate at which a saturated parcel of air (i.e. one in which condensation is occuring) cools as it rises through the atmosphere. At around 7°C/km this is lower than the DALR

Question 162

latent heat

Answer 162

heat absorbed or radiated during a change of phase at a constant temperature and pressure

Question 163

atmospheric instability

Answer 163

the situation when air is at a different temperature to that around it resulting in air rising

Question 164

atmospheric stability

Answer 164

occurs at high altitude where air cannot rise any further as it is not warmer than its surroundings

Question 165

interception loss

Answer 165

rainwater stored temporarily on the leaves, stems and branches of vegetation which is evaporated and does not reach the ground surface

Question 166

throughfall

Answer 166

rainfall initially intercepted by vegetation, which drips to the ground

Question 167

infiltration capacity

Answer 167

the maximum rate at which water, under the pull of gravity, can soak into soil

Question 168

saturated overland flow

Answer 168

the movement of water across the ground, often as a thin film, when the ground is saturated

Question 169

ablation

Answer 169

the loss of ice and snow, especially from a glacier through melting, evaporation and sublimation

Question 170

flux

Answer 170

the rate of energy transfer per unit area

Question 171

anthropogenic

Answer 171

Human-induced changes on the natural environment

Question 172

carbonation

Answer 172

a chemical weathering process by which carbon dioxide dissolves in rainwater forming weak carbonic acid which leads to decomposition of rock

Question 173

freeze-thaw

Answer 173

a mechanical weathering process caused by water, confined in rock joints, expanding by 9% as it freezes, exerting 2,100 kg/cm² pressure, and as a result breaking rocks into smaller fragments