geography paper 1

• asthenosphere

  semi molten layer

  on top of the mantle

  it flows due to convection currents moving the lithosphere above
• atmospheric circulation

  general movements of air around the earth due to pressure and temperature
• climate change

  distinct change in global patterns of climate

  for example temperature or rainfall
• conservative plate boundary

  where 2 plates move next to each other

  friction builds up over lots of years and moves with a sudden jolt

  causes tsunamis, earthquakes

  no volcanos
• convergent plate boundary

  where 2 plates move towards each other and 1 subducts

  causes earthquakes and explosive volcanos
• divergent plate boundary

  where 2 plates move away from each other and magma rises in the gap

  creates shield volcanos with runny lava
• continental crust

  thicker, less dense crust

  makes up the continents
• convection current

  movement of fluid caused by a difference in temperature or density
• Coriolis effect

  effect of the earths rotation on wind movements
• cyclone

  large spinning tropical storm

  forms in the tropics

  has low pressure due to warm air rising and creating areas of low pressure

  intense weather like thunderstorms, winds, rain

  spinning structure because of the spin on the earth
• cyclone formation

  warm air rises and moves from low pressure areas

  air cools and moist air condenses forming thunderclouds

  the storm develops an eye

  storm surges are caused where cyclones push water to land

  the storm loses energy at land so dissipates
• cyclone effects

  winds lift roofs and damage infrastructure

  rainfall causes flooding and contamination of fresh water

  storm surges cause high tides

  landslides happen due to over saturation
• cyclone conditions

  there must be a temperature of 26 C

  the water must be 50 metres deep

  winds must be present

  there must be areas of unstable air

  it must be around the equator but never on because there is no Coriolis effect so the storm would not spin
• eccentricity

  the changing of the orbit of the earth around the sun

  from a circular shape to an ellipse
• eye

  an area of a cyclone with low pressure and calm conditions
• eyewall

  area in a cyclone with the most intense winds, pressure and torrential rain
• ferrel cell

  around 60 degrees either side of the equator

  moist air rises and travels to lower latitudes
• hadley cell

  at the equator

  hot air rises and moves to higher latitudes where it sinks
• polar cell

  60 degrees north and south of the equator

  moist air rises and travels to the poles where it sinks
• fossil fuels

  fuels made of organic material

  for example oil coal and gas
• geological hazard

  hazard caused by processes on land
• greenhouse gases

  gases in the atmosphere that trap energy and heat in the earths systems
• axial tilt

  tilt of the earths axis

  changes from 21.5 and 24.5
• how do convection currents work

  energy heats the fluid asthenosphere

  hot liquid rises up and reaches the top where it cools and sinks

  it is heated again and the cycle continues

  plates are pulled and pushed due to this
• human causes of climate change

  farming increases the amount of methane which is a greenhouse gas

  deforestation cuts down trees which reduces the amount of CO2 being absorbed so there are high levels in the atmosphere

  greenhouse effect traps energy and heat which is then reradiated around the world
• natural causes of climate change

  asteroid collisions would create debris which would block the sun and decrease temperatures

  volcanic activity would create debris which would block the sun and decrease temperatures as well as emitting sulphurous gases which reflect solar radiation

  orbital changes would change the distance from the sun and affect the intensity of the rays
• earths structure

  inner core

  outer core

  lower mantle

  upper mantle -> asthenosphere

  lithosphere

  crust -> top of the lithosphere
• hazard risk

  probability that a natural hazard will negatively affect a population
• hotspot

  an area where hot magmas breaks through the middle of a plate creating a volcano

  not related to plate boundaries
• hurricane

  type of tropical cyclone
• ice cores

  cylinder of ice taken from a glacier

  used to analyse past environmental conditions

  the top of the core is the younger ice and the bottom of the core is the oldest ice

  air bubbles can be analysed for CO2 levels
• immediate responses

  actions that happen as soon as the hazard has happened

  hours, days and maybe even a week after
• inner core

  solid ball of iron at the centre of the earth

  radioactive decay in the core provides the earths internal energy
• inter-tropical convergence zone (ITCZ)

  area surround the equator where global winds converge

  create areas of low pressure and rainy conditions
• lithosphere

  solid rock that lies on the top of the asthenosphere

  the top is the lithosphere is broken into tectonic plates
• long term responses

  actions taken at a delayed response to the hazard

  weeks months and maybe even years
• magma

  molten lava under the earths surface
• mantle

  area underneath the crust

  largest layer

  mainly solid rock

  top layer is dense fluid
• Milankovitch cycle

  cylinder variations in the earths orbit
• ocean currents

  thinner denser crust that makes up the ocean floor