geog, things to remember

name all the different things that make up the upper course of a river (valley shape, erosion, features found and gradient)

valley shape - v shaped valley

erosion type - verticle (downwards erosion)

features found there - waterfalls, interlocking spurs, rapids and gorges, steep gradient

name all the different things that make up the middle course of a river - valley shape, erosion, features found there and gradient

valley - wide and flat

erosion - lateral (sideways)

features found - meanders, oxbow lakes and slip-off slopes (bends found in the inner bend of a river)

gradient - less steep

name all the things that make up the lower course of a river - erosion, features found there and gradient

no valley shape - at the mouth of the river

erosion - lower energy lateral

features found - deltas (flat, trinagle shaped piece of land created by deposition), oxbow lakes, floodplains, levees

deposition is dominant here

what is a valley?

an area of land that a river flows through

describe the formation of a oxbow lake

• Meander in the river forms with erosion on the outer bend and deposition on the inner bend.

• Neck of the meander becomes narrower due to erosion.

• During high flow, the river cuts through the neck, creating a new, straighter channel.

• The old meander is cut off, forming a crescent-shaped oxbow lake

describe the formation of floodplain

• A floodplain forms in the lower course of the river, where it has a wide valley.

• During floods, the river overflows its banks and deposits sediment

• The deposited sediment builds up over time, creating a flat, fertile area on both sides of the river

describe the formation of a waterfall

• A waterfall forms where there is a hard rock layer over a softer rock layer.

• Erosion of the soft rock by the river causes a vertical drop.

• The force of water erodes the base, creating a plunge pool.

• Over time, the waterfall retreats upstream, leaving behind a gorge

what are the 5 factors that affect climate?

altitude - higher altitude means lower air pressure, meaning thinner which holds less heat

latitude - closer the the equator = more direct sunlight and warmer climates, closer to the poles = less direct sunlight and cooler climate

proximity to water - area close to water will have milder climates as water takes longer to warm and cool than land

topography (landform) - mountains can block or alter weather patterns - windward = more rainfall and cooler climate - leeward = dryer and warmer climates, form rain shadows (dry area)

wind and ocean currents = winds can be hot/cold depending from where they come from (hot = gulf stream)

what are the 4 main air masses that effect the Uk’s climate?

polar maritime - north west - cold and wet

tropical maritime - south west - moist and warm

polar continental - north east - cold,warm and dry

tropical continental - south east - hot and dry

what happens at the ITCZ (inter-tropical convergence zone)

since it is found near the equator - direct sunlight hits the land, which heats the air surrounding it, causing it to rise

then that air condenses and cools as it rises, creating clouds and heavy (convectional) rainfall

the rising air means there is less air at the surface, which is why the ITCZ is low pressure

when does the ITCZ shift?

june/july - northward

dec/jan - southward

how do low pressure systems (depressions) form?

• Warm air rises- When air is heated, it becomes less dense and rises.

• Rising air creates low pressure-As the air rises, there’s less air pressing down at the surface = low pressure.

• Air rushes in to replace it- Surrounding air moves in (often from high pressure areas) → this causes winds.

• Condensation and clouds form-Rising air cools, condenses and forms clouds and precipitation (rain, snow, etc.)

how are high pressure systems formed?

• In a high pressure system, cold or cool air sinks toward the Earth’s surface.

• Sinking air means the air molecules are pushed closer together, increasing air pressure at ground level.

• Because air is sinking, it doesn’t rise and cool, so condensation doesn’t happen.

• That means fewer clouds or even clear skies.

• Winds are usually light and weather is settled.

• High pressure systems are often slow-moving and can stay over an area for days or even weeks

are anticyclones high pressure, give the case study and its effects for an anticyclones

yes, they can cause hot, dry weather and heatwaves, for example the summer 2018 anticyclone which caused increased wildfire risk, hosepipe bans and drought warnings

how do tropicals storms form? low pressure system

Sea surface temperatures of 27°C or more cause water to evaporate.

This creates a low pressure zone at the surface.

• Air continues rising & condenses

  forming thick clouds and releasing latent heat, which fuels the storm.

• More air is drawn in

  This creates a cycle: more air is pulled in, rises, condenses, and releases energy.

• Storm starts spinning (Coriolis effect)

  The Earth's rotation causes the system to rotate (anticlockwise in the Northern Hemisphere, clockwise in the Southern Hemisphere).

• Develops into a tropical cyclone

  If wind speeds reach 74 mph (119 km/h), it's officially a tropical cyclone (or hurricane/typhoon

explain the main points for the impacts of climate change on the tuvalu islands

1. Rising Sea Levels

• Caused by melting polar ice and thermal expansion (as oceans warm, they expand)

• Leads to:

  • Coastal erosion

  • Flooding of homes and farmland

  • Contamination of freshwater supplies by saltwater

  • Some parts of Tuvalu are now uninhabitable

2. Increased Storms and Extreme Weather

• Climate change causes stronger and more frequent cyclones

• Tuvalu faces:

  • Storm surges

  • Flooding

  • Damage to homes, crops, and infrastructure

3. Threat to Food and Water Security

• Saltwater intrusion ruins soil used to grow food (e.g. taro and coconuts)

• Groundwater sources are becoming salty, reducing drinking water supply

4. Climate Refugees

• Some residents have already migrated to places like New Zealand due to worsening conditions

5. Environmental & Cultural Loss

• Sea level rise threatens coral reefs, biodiversity, and cultural identity

what is the formation of headlands and bays?

• Soft rock erodes faster than hard rock.

• Soft rock gets worn away, forming a bay.

• Hard rock sticks out as a headland

what is the formation of a cave, to an arch, stack and stump?

• Cave: Cracks in a headland are made bigger by erosion (like hydraulic action).

• Arch: The cave gets deeper and breaks through the headland.

• Stack: The roof of the arch collapses, leaving a tall column.

• Stump: The stack gets worn down by waves until it’s short and stubby

what is the formation of a wave cut notch and platform?

• Waves erode the bottom of a cliff, making a notch.

• The cliff above collapses.

• The cliff moves back, and a flat rock area is left – the platform

what is the formation of a spit?

• Longshore drift moves material along the coast.

• At a bend in the coastline, the material is deposited.

• A spit forms that sticks out into the sea.

• The end may curve due to wind or waves.

• Sometimes a salt marsh forms behind it

what is the formation of a bar?

• Like a spit, but it joins two headlands across a bay.

• It blocks off a bay and can create a lagoon behind it