Physical Geography Flashcards
What Is A Closed System
A closed system is one that has no input or output
What Is The Water Balance
The water balance is the balance between inputs, outputs, stores and flows
What Is The Symbol Equation For The Water Balance
P=E+Q(+-)S
What Is The Word Equation For The Water Balance
Precipitation = Evapotranspiration + Discharge (+-) Change to the stores
What Is Discharge Measured In
Cumecs
cu/m/ecs
cubic meters per second
What Is A Positive Water Balance
When there is more precipitation than evapotranspiration
What Is A Negative Water Balance
When there is more evapotranspiration than precipitation
What Is Deficient Water Moisture
When there is not enough moisture in the soil
What Is Recharging Water Moisture
When soil is gaining more water
What Is Utilisation Of Moisture
When water is being lost from the soil due to use or evaporation
What Is A Surplus Of Moisture
When there is too much moisture in the soil
What Is Discharge
Discharge is the volume of water in a river as it passes a particular point at a particular time
How Do You Measure Discharge
Cross sectional area x river’s mean velocity
What Do Flood Hydrographs Do
They let us examine the relationship between rainfall and discharge
What Is The Rising Limb On A Flood Hydrograph
The rising limb is the peak of the rainfall / discharge
What Is The Lowering Limb On A Flood Hydrograph
The process of discharge decreasing
What Is Lag Time
The time between when the peak rainfall and peak discharge
What Is Lag Time
The time between when the rain stops and the peak discharge
How Does Deforestation Affect Flood Risk
Deforestation causes high risk of flooding as there is less storage, reduced interception and evapotranspiration which increases run-off
How Does Agriculture Affect Flood Risk
Over grazing of cattle can lead to less vegetation and compact soil, increasing run off.
Drainage systems, ditches, and plough all reduce the risk of flooding
How Can Coastal Influences Affect Flood Risks
High seasonal tides affect areas close to the sea. Insufficient planning control allowing high density buildings alone the coast line. Storm surges and tropical cyclones can result in high water levels in rivers and low lying areas
How Does Climatology Affect Flood Risks
Sudden increases in temperature can cause snow to melt, and decrease in temperatures cause snow to form permafrost; both can increase flood risks
How Does Urbanisation Affect Flood Risk
Highly impermeable surfaces like concrete are everywhere. River straightening can lead to a faster delivery of water downstream
Why Are Dams Created
Dams are created to hold water back from as a reservoir or to prevent water from entering downstream too fast
What Are Levy’s
Levy’s are added embankments to make the sides of a river higher
Define Flash Floods
Heavy rainfall falls onto saturated grounds and cannot be absorbed. This causes rapid flooding
Water Vapor Statistic
Globally, water vapor concentration in the lower atmosphere has increased by 3-4% since 1970
Northumberland Flood : Case Study
Key Facts
- 80mm of rainfall in 6 hours
- The river was geomorphicaly changing, the sides of the river valley were unstable
- The unstable valley debris caused natural dams in the river
- When the dam broke it caused a flash flood
Convective Storms
Sever local storms associated with thunder, lightning, heavy rain, hail, strong winds and sudden changes in temperature. They mostly occur during the warm summer months. They occur when heat provides enough energy to the atmosphere, driving evapotranspiration and convection current which forms the storm.
Thinhope Burn : Case Study
Key Facts
17th of July 2007 a flash flood in the river valley of Thinhope Burn caused the river levels to rise from 2m to 55m in less than 2 hours. It was a local storm as no other areas flooded, but the river channel (which was only a few meters wide and very stable) could not hold all the water. Peak rainfall was 42mm p/h and a total of 82mm fell in 6 hours
Explain Positive Feedback
Positive feedback is a change that generates further change. The initial change gets worse and worse because of the knock on effects
What Is Another Name For Positive Feedback
The Albedo effect
Give An Example Of The Albedo Effect
The rainforest is dark and absorbs a lot of solar radiation. the solar radiation heat the atmosphere around the forest, the heat then draws in a low pressure system from the Atlantic which creates a rainy climate over the Amazon. if the trees were to be cut down to create pastures, the ground would be light and reflect the radiation which cools the local atmosphere and creates a high pressure system which produces less rain and so there are less trees and the cycle continues
What Are The Four Components Of A System
Inputs
Outputs
Flows
Stores
What Does A Low Albedo Do
Absorb a lot of solar radiation
Components Of A System Before Deforestation
High inputs = high precipitation
High outputs = high evapotranspiration
Flows = channel flow, stem flow, infiltration
Stores = ground water, soil, vegetation, interception
Components Of A System After Deforestation
Low inputs = less precipitation
Low outputs = Less evapotranspiration
Flows = no flows
Stores = only in river
What Is High Drainage Density
Lots of rivers going to the same place
What Is Water Abstraction
Water abstraction the the process of removing water from the ground for use
Why Were Ground Water Levels Low After The Industrial Revolution
Because we over abstracted the water to use in the industrial revolution
What Happens If Ground Water Is Not Abstracted
Potentially, the water levels can get to high and cause flooding in underground structures as it did in the London Underground
Explain Why Chalk Is A Good Place To Abstract Water
Because the acid in the water create ponds of water in the chalk which can be easily abstracted. Chalk is a porous rock
Pickering Case Study Facts
- Surrounded by the North Yorkshire Moors
- Moors store a lot of water and carbon
- Pickering cannot use hard engineering as it would increase the flood risk downstream
- Planting forests is a natural flood defense
- Diverting rivers into flood plains can reduce flood risks
Measurements Of Carbon
Carbon is measured in petagrams. One petagram is equal to a gigaton. A gigaton is equal to 1 million metric tons
What Type Of System Is The Carbon System
It is a closed system, no inputs or outputs
The Biggest Store Of Carbon Is In The …
Lithosphere
The Definition Of The Carbon Cycle
The carbon cycle is a closed system meaning no inputs or outputs. It has 6 main stores: plants, soil, fossil fuels, oceans, the earths crust and the atmosphere. The 5 ways carbon is placed into stores are; litter fall, rivers, burial to sediment, ocean uptake and photosynthesis
What Is Net Carbon Sink
More carbon entering than leaving
Net Carbon Source
Less carbon entering than leaving
Flows Of Carbon: What Are Fossil Fuels
Energy stored in substances such as oil, gas and coal
Flows Of Carbon: Peat
Peat is undecayed dead organic matter
Flows Of Carbon: Photosynthesis
The process of plants turning CO2 and water into glucose and oxygen
Flows Of Carbon: Respiration
The conversion of oxygen into CO2
Flows Of Carbon: Anthropogenic
Things to do with humans and people
Flows Of Carbon: Oceanic Carbon Pump
The release of carbon from the ocean at the equator due to convection current
Flows Of Carbon: Volcanic Activity
Is the movement of magma in the earths mantel but also the eruption are replenishment of volcanoes
What Is The Carbon Budget
The carbon budget is a goal to not raise global temperatures above 1.5 degrees above the average temperature before industrial revolution
How Can We See The Long Term Carbon Levels / Climate Change
We can see long term carbon levels by reviewing ice core data to analyze trapped gasses
How Can We See The Medium Term Carbon Levels / Climate Change
Pollen extracted from peat bogs and lake bed cores to check carbon levels, as well as tree rings to see the average temp for the year level
How Can We See The Short Term Carbon Levels / Climate Change
The IPCC, it is virtually certain that humans are to blame for unequivocal global warming
What Is Our Best Option To Change Climate Change
Mitigation
