Flashcards in Weather And Climate Deck (69):
Different areas of the earth receives different amounts of solar radiation: there is a surplus of heat energy at the equator and a deficit at the poles. Three circulation cells in each hemisphere redistribute heat
What are the 3 circulation cells that redistribute heat?
At the equator, warmed air rises to 15 KM, causing low pressure. The air current divides, cools and moves north and south to form Hadley cells. The cooled air sinks at 30 degrees north and south of the Equator, leading to high pressure.
Some of the cooled air moved back towards the equator as trade winds. The rest travels towards the poles, forming the lower part of Ferrel cells
At 60 degrees north and south, the warmer air of the Ferrel cells meet colder polar air. The warmer air rises to form polar cells. This air travels to the poles, where it cools and sinks, forming areas of high pressure
Ocean currents also transfer heat energy from areas of surplus (Equator) to areas of deficit (poles). Wind-driven surface currents move warm water towards the poles and colder water towards the Equator. In the Arctic and Antarctic, water gets very cold and dense so it sinks. Warmer water from the Equator replaces this surface water, creating ocean currents, such as the Gulf Stream. Cooled water flows back towards the equator, forming cold currents, such as the Humboldt current
The average climatic conditions of the earth change naturally over time, what does this create?
Both warmer and colder periods
What is the Quaternary period?
The Quaternary period covers the last 2.6 million years, when there have been: more than 60 cold periods of ice advances lasting about 100 000 years, warmer interglacial periods lasting about 15 000 years
Explain recent temperature changes
In the last 250 years the earths temperature has risen significantly compared to before. Average temperature in the middle of the last ice age was about 5 degrees below today's average temperature
What are the milankovitch cycles?
These are long term changes to the earths orbit and position, changing how much solar radiation the earth receives - resulting in changes in climate
What is the eccentricity cycle?
The earths orbit changes approximately every 100 000 years. More circular orbit ➡️ cooler periods; more elliptical orbit ➡️ warmer periods
What is the Axial tilt cycle?
Roughly every 40 000 years the tilt of the a Earths axis varies. Greater angle of tilt ➡️ hotter summer and colder winter
What is the presses ion cycle?
The earth 'wobbles' on its axis roughly every 24000 years, changing the direction the axis if facing. This can affect the direction the axis is facing. This can affect the differences between seasons
What are other natural causes of climate change?
Solar radiation levels may vary, lower solar radiation makes glacial periods more likely; higher solar radiation leads to interglacial periods.
A large scale volcanic eruption can eject ash and dust into the atmosphere. This acts as a blanket over the earth, blocking out solar radiation, causing temperature changes to fall for a time
What is the evidence if climate change?
Historical sources, such as diaries
Ice cores trap volcanic ash, microbes, air bubbles. These reveal information on climate when ice is formed
Preserved pollen provides evidence on warm and cold growing conditions
What is a key contributer to global warming?
Rising greenhouse gases, which are released by human activities including industry, transport, energy production and farming
What is the enhanced greenhouse affect?
Human activity releases increasing levels of CO2 and other greenhouse gases into the atmosphere, increasing the greenhouse affect - more warming
How is heat trapped in the atmosphere?
Heat energy from the sun passes through the atmosphere and heats up the earth
Much of this heat energy is radiated back into space
Greenhouse gases in the atmosphere, such as CO2, trap some of the heat
How does industry impact climate change?
Rising demand for consumer goods increases production, burning more fossil fuels, which relate greenhouse gases
How does energy impact climate change?
New technologies and population growth increase demand for electricity produced growth increase demand for electricity produced from coal, oil and natural gas, which all produce greenhouse gases
How doe farming impact greenhouse gases?
Global population growth increases demand for food. Mechanisation burns more fuel, and the demand for meat for western-style diets increases methane levels
How does transport impact climate change?
Rising affluence increases car ownership and air travel p, releasing more greenhouse gases into the atmosphere
What a re the negative impacts of climate change in the environment?
Melting ice sheets and retreating glaciers add water to oceans, making sea levels rise. Arctic melting could cause the Gulf Stream to move further south leading to colder temperatures in Western Europe.
Rising sea levels will cause coastal flooding. Soils will become contaminated with salt causing plants to dies
What are the impacts of climate changes in people?
Changes in climates near the equator, such as Africa's Sahel, could mean longer periods of less rainfall, so lower crop yields
Many low-lying islands like the Maldives face greater flood risk from rising sea levels. There will be more coastal flooding, loss of beaches and loss of coral reefs. Some islands will have to be evacuated
Explain past climate changes
The climate has been very different in the past. During the medieval warm period (950-1100) higher temperatures meant greater crop yields and a growing population. This was due to solar radiation
During the little ice age (1600-1685) temperatures were low enough to freeze the Thames, due to increases volcanic activity and decreased solar radiation.
What is the uk's climate like today?
Today the uk has a temperate, wet climate. Extreme weather us rare, but the meeting of major masses makes frontal rainfall common
How does the uk's location impact climate change?
The U.K. Is located between 50-60 degrees north. This and other factors have an impact on climate.
(Impact of the uk's location) what is the maritime influence?
Most of the air reaching the uk contains losts of moisture as we are surrounded by sea leading to rainfall all year
(Impact of the uk's location) what are prevailing winds?
The main or prevailing wind for the uk comes from the south west. This air travels long distances over the Atlantic Ocean bringing moisture leading to more rainfall
(Impact of the UKs location? What is the North Atlantic drift?q
This ocean current brings warm water north to the uk. In the winter this makes the uk climate milder than would be expected for its latitude
(Impact of the uk's location) what is atmospheric circulation?
The U.K. In near the 'boundary' between the northern Ferrel and Polar circulation cells. This is where warmer air from the south and cooler air from the north meet, causing unsettled weather
(Impact of the uk's location) what is altitude?
The higher an area is, the cooler and wetter it is, so areas in the uk vary
What are tropical cyclones also a know as?
Hurricanes and typhoons
What is the earths atmosphere constantly doing?
It's in constant motion, transferring heat around the earth
What sources do there need to be to form a tropical cyclone?
Tropical cyclones need a source of warm, moist air and warm ocean temperatures (27 degrees C plus)
What 3 steps make a tropical cyclone?
Rising air causes thunderstorms, which group together, making a strong flow
An area of very low pressure forms at the centre of the converged storms
The storms rotate, accelerating in and up, forming a tropical cyclone
Where do tropical cyclones form and how are they created?
Tropical cyclones form in tropical areas where a rotation force, created by the Coriolis effect, forms parts of the global circulation of the atmosphere. The rotation is due to deflection of winds moving north and south of the equator
What are the characteristics of a tropical cyclone?
Very low pressure
Form a cylinder of rising, spiralling air surrounding an eye of defending, high-pressure air
Cloud banks Calle dryer eye wall surround the eye
Often 400 Km wide and 10 Km high
What is the frequency of tropical cyclones?
Tropical cyclones are more likely to happen: June - November in the northern tropics and November - April in the southern tropics
They are more likely to happen in cooler years, but numbers are hard to predict
Tropical cyclone movement
Cyclone movement is determined by the prevailing winds and ocean currents
The cyclones track in influenced by how far it travels over the ocean: it will collect moisture, increasing its strength
Tropical cyclones can travel 600 km a day at 40 km/h
Cyclone movement can be forecast using satellite images
How are storm surges in a tropical cyclones hazards?
Tropical cyclones can cause a large mass of water to hit land, causing damage to beaches and coastal habitats
How are high winds in tropical cyclones hazards?
Winds as high as 240 km/h can uproot trees and buildings, potentially causing injuries and loss of life
In tropical cyclones how is intense rainfall a hazard?
Heavy persistent rainfall can lead to flooding, damaging property and leaving people stranded
In tropical cyclones how are landslides a hazard?
Intense rainfall causes the soil to be saturated and become heavy. This saturated soil then slides downhill
In tropical cyclones how is coastal flooding a hazard?
Damage to property and lives is increased due to flooding
What is the saffir Simpson scale?
This scale classifies tropical cyclones into 5 categories
Go to page 36 and look at the
Saffir Simpson scale
What are the key facts of hurricane sandy?
The hurricane travelled across the Caribbean Sea, affecting the island nations of Jamaica, Cuba and Haiti, before moving north to reach USA
It reached New Jersey on 29 October 2012
By the time the hurricane reached land, wind speeds of 129 km/h were recorded
The storm surges caused most of the damage to the east coast states
The use of social media such as Twitter and photos uploaded to Flickr with damage assessment
What were the social impacts if hurricane sandy?
Death toll of at least 150 people
Many areas left without electricity
Homes and businesses damaged
Schools closed for days
What were the economic impacts of hurricane sandy?
Estimated property damage: US$65 billion
Government had to pay for petrol to be brought in as supplies ran out
Income from tourism affected by cancellation of New York marathon
What were the environmental impacts if hurricane sandy?
Storm surge caused significant damage to coastal nature reserves like the prime hook national wildlife refuge in Delaware
Raw sewage leaked into the waters around New York and New Jersey, damaging habitats
What the response to hurricane sandy?
Individuals - the concert for sandy relief with artists such as Bon jovi
Organisations - the American Red Cross helped by providing relief to victims
Government - billions of dollars were voted through legislation to help with rebuilding and supporting victims. New York set up a new local government office to support the rebuilding
What are the key facts of typhoon Haiyan?
Formed on 2 November 2023 in the South Pacific Ocean , close to the Federated states of Micronesia
When the typhoon reached land, wind speeds of over 300 km/h were recorded
Most of the damage caused by the typhoon was on the islands of Samar and Leyte
Flooding and landslides were reported across the Philippines
What were the social impacts of typhoon Haiyan?
An estimated 6000 people killed and many more missing
Significant loss of power
An estimated 600 000 people displaced from their homes
Many homes left were destroyed
What was the economic impact of typhoon Haiyan?
Estimated damage: US$2 Billion
Damage and disruption to infrastructure blocked transport across islands, making provision of aid and support difficult and expensive
What were the environmental impacts of typhoon Haiyan?
Mangroves damaged across the islands
Oil spills from a tanker caused sea pollution
What was the response to typhoon Haiyan?
Individuals - people in countries such as the UK and Canada gave money towards the relief efforts
Organisations- the world health organization coordinated the international response to help the Philippine government meet the acutely need for health care services
Governments - in order to direct funds to help support the aftermath, the Philippines were put in a 'state of national calamity'. Aid in the form of loans and grants was provided by countries like the uk, which gave £10 million package including emergency shelter, water and household items
What are arid areas like?
In arid areas, the normal climate is dry, because they normally have high pressure, leading to low precipitation
the key factors in whether an area is likely to suffer from drought are:
How it gets precipitation- at any time or in a rainy season
When precipitation occurs - during winter when soil can absorb rain more easily, or in summer
What are arid environments like?
Permanent low precipitation. The Sahara is arid; the kalahari is semi-arid
10-250 mm precipitation a year
High pressure conditions, no cloud cover
Mostly located in the tropics (between 23.5 degrees north and 23.5 degrees south of the equator)
What are drought conditions like?
Temporary low precipitation conditions
In the UK, drought is 15 consecutive days without rainfall
High pressure conditions, no cloud cover
Located anywhere globally
What are the natural causes of drought?
Meteorology - this is where an area receives less than average precipitation. In the UK, high pressure ( blocking anticyclone) forces away the low pressure systems that bring rain around it. This means no rain falls over all or part of the UK for weeks.
Hydrological - this is where the hydrological cycle receives less rainfall than normal. Less precipitation means groundwater supplies and reservoirs are not refilled, leading to drought conditions
Global circulation and drought
Global circulation and drought makes some locations more vunrable to drought. Where the Hadley and Ferrel circulation cells are, such as Africa's Sahel, descending dry air means there is little precipitation. Rainfall occurs during a wet season; if the rains do not come, the areas has drought conditions
Explain California drought, 2012 to present
In January 2014, California was experiencing its third year of drought and a state of emergency was declared. Lower than normal rainfall and snowfall on the west coast and dependence on the overused Colorado river,mad caused water supplies to drop
What were the main hazards in the California drought?
Subsidence as groundwater levels dropped, causing land to settle at a lower level
Contamination of land and drinking water by seawater, drawn inland by a lack of pressure
Wildfires which started and spread quickly, as vegetation was so dry
How have the Californians responded to the drought?
Government - ran public education campaigns, eg save our water,
Brought in state laws requiring a 25% cut in water use in California
Organisations - university of California erase arch project for effectively managing groundwater
Individuals - farmers encouraged to use water-efficient irrigation, such as drip irrigation, homeowners encouraged to check for water leaks, protesters campaigned against companies selling bottled local water
What are the impacts on ecosystems in California?
Water diverted, so wetlands and rivers get less, impacts on natural environment and wildlife e.g.rivers to low for salmon to breed
Warm and windy weather led to wildfires, environmental damage, air pollution, destroys wildfire and habitats
What are the impacts on people in California?
Costing California US$2.7 billion a year, less state money to spend on services for people
Increased extraction from groundwater/aquifer casing subsidence, infrastructure and buildings damaged
Warm and windy weather led to wildfires, risk to people lives, property
542 000 acres taken out of crop production, loss of food and income
Explain Ethiopia 2015 drought
Ethiopia has suffered multiple droughts since the 1980s, when the short rainy season began to get shorter, and the long rainy season got later and less predictable.n85% of the people in Ethiopia live in rural areas and rely on agriculture, so low rainfall can be devastating. The 2015 drought was the worst in 30 years
What was the impact of Ethiopian drought on people?
Death of livestock causes a food crisis
Loss of crops means maize price rockets
People eat less, become weak from malnutrition and more vulnerable to disease
Girls have to walk further to get water so cannot go to school
Long grasses used for roofing cannot grow, so homes are unprotected
What is the impact on the ecosystem from the Ethiopian drought?
Loss of habitat for fish and wildlife due to low water levels in reservoirs, lakes and ponds e.g. Borkena wetland
Increases disease in wild animals, because of reduced food and water
Migration of wildlife
Loss of 200 000 hectares for forest every year due to forest fires
Extinction of done species e.g. Gravy zebras
Wind and water erosion of soil