Weather and climate Flashcards
What affects our weather and climate?
Jet streams : form at the boundaries of the main circulation cells where there is a temp difference
- These streams affect the movement of weather systems and can change the weather for different areas.
Oceanic circulation : surface ocean currents driven by wind movement distribute energy
- warm currents flow away from the equator while cold currents flow towards
Natural causes of climate change
Eccentricity : every 100,000 years, the earth changes from a spherical (glacial) to an elliptical shape (interglacial).
Volcanism : ash and dust into the atmosphere blocking out the sun (volcanic winter) disrupts climate globally.
Evidence of climate change
Dendrochronology : Trees produce growth rings as they grow
Wide growth rings - warm, wet climate
Thin growth rings - Cold, dry climate
Ice Cores - Snow compresses into ice which captures information about the climate during the formation
Drilling into ice sheets to find pollen & ash
Significance of the UK’s location - Altitude
Altitude - temp reduced by 1°C for every 100m above sea level
Air cooled over highlands which moisture condenses and precipitates over the West (relief rainfall)
Less cooling / condensing on the East as air meets the west first.
Significance of the UK’s location - maritime influence
Warm, moisturised air from SW prevailing winds
North Atlantic Drift means warm water from Gulf of Mexico and the equator.
-> high rainfall in the west
Surrounded by the ocean so consistent rainfall.
Formation of cyclones
High temperature leads to air rising away from ocean surface, resulting in thunderstorms.
Storms group together creating warm rapidly rising air, producing an area of extremely low pressure.
Hurricane Sandy impacts on New York
Social:
9 million homes power cuts and 650,000 homes damaged
New York streets and subway flooded.
Economic:
$1.1 billion in water pipes & sewage reparation
$19 billion damage costs
Hurricane Sandy responses to New York
Individuals:
Use of builders to rebuild homes.
People moving in with relatives and using shelters.
Government:
$60 billion to victims in aid
Agriculture Department promised $6 million for emergency food assistance and repairing farmlands
Hurricane sandy impacts on Cuba
Social:
17000 homes destroyed
No electricity or fresh water
Economic:
Airport roads blocked - no tourism revenue
$2 billion in losses
Hurricane Sandy responses to Cuba
Individuals:
Moved in with friends / relatives or holding homes
Materials provided by the government to rebuild homes - no insurance
Governments:
Electrician teams within hours of disaster sent from Santiago Province
Military teams to remove rubble and 6 million M^3 of trees
Natural causes of drought
Meteorological refers to the dryness of an area eg. Less precipitation than normal
Hydrological refers to the impact of low precipitation on a hydrological system eg. Loss of soil moisture means river water is difficult to access leading to over-reliance on groundwater and reservoirs.
Human causes of drought
Dams act as flood defences to create reservoirs as stores of water.
Restrict flow of water leading to a drop in water levels downstream,
Deforestation as without trees intercepting rainfall to the atmosphere, local rain cycle is disrupted creating areas of high pressure and less rainfall.
Impacts of drought in California
Water became scarcer due to subsidence - As surface water flow decreases, water is increasingly extracted from groundwater and aquifers to maintain supplies.
This can change the structure of the land causing it to settle to a lower level, damaging buildings and infrastructure such as San Joaquin Valley.
Responses to drought in California
Various government departments such as the Department of Water resources and the SWRCB introduced measures to deal with the drought:
- Information and education programmes to use as little water as possible eg. gardens
- Warning some areas that they will be given limits on how much water they will recieve
- Limiting flows during winter months to try build reserves for later in the year when demand is higher
Impacts of drought in Ethiopia
For farmers, unreliable rainfall makes planning difficult - It’s harder for them to know when to plant their crops and which crops to plant as crops they have used for generations may no longer do well.
For livestock farmers, when land becomes too dry to support vegetation, there is less food and water for their plants and animals.
Reduced food supply leads to increases in prices, affecting the poor and marginal people, causing widespread malnutrition and hunger which has led to famine.
