climate Flashcards
yes (34 cards)
diff types of climates
Tropical equatorial climate
Tropical monsoon climate
Cool temperate climate
Tropical equatorial climate
Generally high temperatures all year round, about 27 degrees celsius
Small annual temperature range of about 2 degrees celsius to 3 degrees celsius
High annual precipitation of more than 2000mm
Precipitation falls evenly throughout the year (no distinct months where it is very dry or very wet)
Location: Between 10 N and 10 S of the equator
Examples:
Havana, Cuba
Singapore
Tropical monsoon climate
Generally high temperatures all year round, at about 25 degrees celsius
Small annual temperature range of about 3 to 4 degrees celsius
High annual precipitation of more than 1500mm
Distinct wet and dry seasons
Location: Between 5 to 30 N and 5 to 30 S of equator
Examples:
Chittagong, Bangladesh
Kochi, India
Cool temperate climate
Temperature varies as there are four distinct seasons of spring, summer, autumn and winter
Large annual temperature range of about 21 degrees celsius
Annual precipitation is between 300 to 900mm
Precipitation falls evenly throughout the year.
Location: Between 45 to 60 N and 45 to 60 S of equator
Examples:
London, UK
Paris, France
Latitude
Due to the Earth’s spherical shape, the angle at which the sun’s rays strike the Earth’s surface varies at different parts of the Earth. The higher the latitude (from the equator), the smaller the solar angle, therefore solar radiation is less direct and spread over a larger area. This means solar radiation is less concentrated, leading to lower temperatures.
Altitude
At higher altitudes, air is less dense and air pressure is lower. This means there are fewer air molecules at higher altitudes, which means lower average energy, leading to lower temperatures.
Air rarely absorbs light/radiation. Instead, ground surfaces absorb energy, which is transferred to the air through conduction and convection.
Type of surface
Dark surfaces generally absorb more light/radiation, resulting in higher temperatures. On the other hand, light-coloured surfaces generally reflect more light/radiation, resulting in lower temperatures.
Urban areas tend to thus have higher temperatures than the surrounding rural areas because:
Urban areas comprise larger areas of dark surfaces (e.g. roads) which absorb more solar radiation and radiate more heat compared to forests and water bodies.
Glass-covered skyscrapers reflect sunlight to the ground surface. This increases absorption of solar radiation and heat radiation by ground surfaces, leading to higher air temperatures.
Distance from the sea
Maritime effect = effect that large bodies of water such as oceans have on climate of coastal areas, which result in a smaller annual temperature range
Continental effect = effect that continental surfaces have on climate of inland areas, resulting in larger annual temperature range
Coastal areas (nearer to sea)
Due to the maritime effect, they experience cooler summers and warmer winters.
Lower annual temperature range
Sea heats up and cools down more slowly than land. Because of this, during the winter, the sea is warmer than land, warming the air along coastal areas. During summer, the sea is cooler than land, cooling the air along coastal areas.
Inland areas do not experience this moderating influence of the sea, and instead experience the continental effect.
Inland areas (further from sea)
Due to the continental effect, they experience warmer summers and cooler winters.
Higher annual temperature range
Sea heats up and cools down more slowly than land. Because of this, during the winter, the sea is warmer than land, warming the air along coastal areas. During summer, the sea is cooler than land, cooling the air along coastal areas.
Inland areas do not experience this moderating influence of the sea, and instead experience the continental effect.
Ocean Currents
In the interior of northern continents, large landmasses experience a continental effect due to the lower heat capacity of land. This means that land heats up faster in summer but also loses heat more rapidly in winter, resulting in a larger annual temperature range compared to the sea. Coastal locations, on the other hand, experience maritime effects because water has a higher heat capacity. This allows the ocean to heat up more slowly in summer and retain heat longer in winter, leading to cooler summers and warmer winters with a smaller annual temperature range.
Ocean currents, such as the Warm Gulf Stream, further moderate temperatures by transferring heat. These warm currents lower the annual temperature range, especially along the western coast of Europe. This effect is amplified when onshore winds carry the warmth from the ocean toward the coast, helping to regulate temperatures in nearby coastal regions.
Cloud Cover
Cloud cover is the extent to which the sky is covered with clouds. During the day, clouds reflect a large portion of the sun’s energy back to space, keeping the earth’s surface cool. Without clouds, large amounts of the sun’s energy can reach the earth, heating up the earth’s surface quickly and leading to higher air temperatures.
At night, clouds absorb more of the heat that is radiated from the earth’s surface and prevent it from escaping into space, which keeps the air warm at night. Without the presence of clouds, more of the heat radiated from the earth’s surface would escape into space, resulting in the air near the earth’s surface to be cooler.
Thus, it is evident that cloud cover influences the temperatures during day and night, and there will be a smaller difference between day and night temperatures when there is more cloud cover.
factors that affect natural variability of climate
Changes in the Earth’s orbit and angle of tilt
Sunspot occurrences
Large-scale volcanic eruptions
Changes in the Earth’s orbit and angle of tilt
Orbit shape
process: The Earth’s orbit stretches from circular to elliptical shape and back
cycle: 100,000 years
Impact: When the Earth’s orbit is elliptical shape, more radiation will reach the Earth at the planet’s closest approach to the sun than the farthest departure from the sun, stronger changes in season
Tilt
Process: The Earth’s axis varies back and forth between 21.5 degrees and 24.5 degrees
Cycle: 41,000 years
Impact: When tilt decreases, the hemispheres will lead further away from the sun, leading to warmer winters and cooler summers, enabling build up of large ice sheets in the higher latitudes, cooling down the Earth.
Sunspot occurrences
Higher sunspot activity = higher amounts of solar radiation from the sun
Sunspots have lower temperature -> areas around the sunspots will have more solar radiation from the sun -> higher temperatures on Earth
High sunspot activity -> high annual surface temperatures
Cycles every 11 years
Between 2000-2008, solar radiation decreased but Earth’s temperature increased -> human activities play a larger role in influencing the Earth’s temperature
Large-scale volcanic eruptions
Global temperatures decrease after a large volcanic eruption
- Volcanic ash reflects more solar radiation back into the atmosphere
- Less radiation reaches Earth, cooling Earth down
- CO2, H2O, SO2, dust, and ash absorb and reflect solar energy back into space,
offsetting the greenhouse effect
Burning of fossil fuels
Fossil fuels have high carbon content
The burning of fossil fuels such as coal, oil and natural gas produces large amoun ts of carbon dioxide and other greenhouse gases which contribute to the enhanced greenhouse effect
Fossil fuels are burned to create energy for human activities such as agriculture, industries and urbanisation
The use of fossil fuels increased steeply since the start of the industrial revolution in the 1880s, contributing to more than 35 billion tonnes of carbon dioxide emissions each year
Changing land use
Changing land use for agriculture, industries and urbanisation may involve large scale deforestation which contributes to the enhanced greenhouse effect
The large-scale removal of forests occur due to the need for resources and land
Deforestation results in increased levels of carbon dioxide because it reduces the number of trees that absorb carbon through photosynthesis, releasing their stored carbon to the atmosphere
Clearing of trees also exposes the soil beneath to sunlight, which increases soil temperature and the rate of carbon oxidation
Globally, tropical deforestation contributes to about 20% of annual greenhouse gas emissions
effects of climate change list them down
Rise in atmospheric and global sea surface temperatures.
Changes to ocean circulations.
Changes in precipitation.
Rise in atmospheric and global sea surface temperatures.
The Earth’s atmospheric temperature has been increasing due to the emission of large amounts of greenhouse gases. Most of the excess heat trapped by these gases has been absorbed by the world’s oceans, causing their temperatures to increase. Average temperatures of oceans have been increasing as over the last century, the sea surface has warmed by slightly over 1 degree celsius. However, this increase is uneven with some parts of the ocean warming faster whilst other parts will be cooler.
Changes to ocean circulations.
Normally, warm surface water moves from the equator to the poles due to winds. The water then cools, becomes denser and sinks. This cold water then spreads along the bottom of the ocean, forming cool subsurface flows, and eventually rises back towards the surface of the ocean.
However, climate change is expected to slow down this global circulation of water. This is because water at the surface gains heat due to rising atmospheric temperatures. The water therefore becomes less dense. This reduces the sinking of water at the poles, and thereby slows down the flow of water.
Example: Ocean current in the Atlantic Ocean has slowed by about 15%.
Changes in precipitation.
Impact of excessive rainfall on terrestrial ecosystems.
Climate change is causing an increase in excessive rainfall in wet areas.
The warmer air results in increased water vapour in the atmosphere, especially in areas where surface water such as rivers, lakes and seas are present. This is due to warmer air being able to hold more water vapour and due to increased evaporation. As such, in these areas, total precipitation and the occurrences of excessive rainfall are expected to increase.
Example: The Poles, parts of Southeast Asia and central Africa
Impact of droughts on terrestrial ecosystems
Climate change will result in dry areas becoming even drier, and may increase the occurrences of droughts in these areas. The warmer atmospheric temperatures increase evaporation, which reduces surface water and dries out soil and vegetation. This makes dry seasons in these areas even drier, resulting in droughts. The lack of moisture can further reduce the occurrence of rain.
Example: Southwest USA and parts of the Sahel region in Africa
Disruption of marine food webs
The slowing down of ocean circulation can disrupt marine food webs. Ocean circulation transports heat from the tropics to the poles and allows for the exchange of nutrients and oxygen between the surface and deep waters. However, as the sinking of water is reduced at the poles, warm surface waters mix less with cooler, deeper water. With reduced mixing of deep and surface waters, aquatic organisms living near surface waters, especially phytoplanktons, would not get their supply of nutrients from the deep ocean. As phytoplanktons form the base of the food web, the species higher up in the food chain, such as fish and whales, will decrease due to a lack of food. The entire ecosystem will be affected.
Example: Phytoplankton levels in the North Atlantic have dropped by 10% since the 1800s.
Threats to coral reefs
Corals are highly fragile ecosystems and vulnerable to coral bleaching. Increasing ocean temperatures cause algae that lives in corals to leave them. Since algae is the coral’s primary food source, they will turn white without algae and become vulnerable to diseases, which may lead to death.
