Weather and Climate

Rain

Wind

Climate

Temperature

Humidity

Factors

Factors

Monsoon

Cool temperate

Equatorial

Climate Change

Factors

Man made (anthropogenic)

Natural

Impacts

Efforts to combat climate change

Variations in solar output

Volcanic eruptions

Deforestation

Sea Level Rise

More extreme weather events

Spread of infectious diseases

Convectional rain

  • The surrounding air is also heated, becomes unstable and less dense. The air then expands and rises
  • As the air rises, its temperature drops, allowing the relative humidity of the air to increase to 100%. The air has cooled to dew point temperature.
  • Condensation then occurs when the air is cooled below dew point temperature and there is condensation nuclei for water vapour in the air to condense on, forming tiny water droplets
  • The water droplets in the air merge with each other in a process called coalescence, resulting in the formation of clouds containing water droplets.
  • When water droplets grow large and heavy enough, they fall to the earth's surface as precipitation.

formed when air moves frrom an area of high air pressure to an area of low pressure

  • The earth's surface is heated up by the sun's energy

Relief Rain (Orographic)

  • Warm moist air carried by prevailing winds from the sea is forced to rise up the windward side of the mountain.
  • As the air rises, its temperature drops with altitude, allowing the relative humidity of the air to increase to 100%. The air has cooled to dew point temperature.
  • Condensation then occurs when the air is cooled below dew point temperature and there is condensation nuclei for water vapour in the air to condense on, forming tiny water droplets
  • The water droplets in the air merge with each other in a process called coalescence, resulting in the formation of clouds containing water droplets.
  • When water droplets grow large and heavy enough, they fall on the windward side of the mountain as precipitation.

Land and Sea Breezes

During the day

  • The land heats up faster than the sea as water has a higher specific heat capacity.
  • Air over the land surface becomes unstable and less dense due to heating, expands and rises, leaving behind an area of low pressure over the land
  • Air over the sea surface is denser compared to air over the land surface due to a less intense heating effect from the sea, and sinks, creating an area of high pressure over the sea.
  • As air pressure over the sea is higher than over the land, air moves from the sea to the land as a sea breeze.

Monsoon Winds

Southwest monsoon

  1. Time of Year
    From June to September

How to remember

  1. September ▶ SouthWest Monsoon
  2. SouthWest ▶ South Winter
  1. Season
    The northern hemisphere experiences summer while the southern hemisphere experiences winter
  1. Temperature + Pressure
    Air over Asia in the northern hemisphere is warmer and less dense due to the greater heating effect caused by lower specific heat capacities of land masses. It rises up, leaving behind a low pressure area in Asia.
    Air over Australia in the southern hemisphere is cooler and denser due to less intense heating effect caused by land masses with lower specific heat capacities.
    It sinks, creating a high pressure area in Australia
  1. Wind Direction
    As air pressure over 💙: Australia💙 is higher than ❤Asia❤,
    air from 💙Australia💙 moves to the ❤Asia❤
  1. Eventual Wind Direction
    The winds then become the southwest monsoon winds

Latitude

Altitude

Distance from the sea

Cloud Cover

Continental effect

  • The Earth is tilted at 23.5 on its own axis.
  • As a result, the solar angle at higher latitudes is smaller. This means the solar energy in the sun's rays are spread out over a wider area and less concentrated.
    However, at lower latitudes the solar angle is greater. The solar energy in the sun is concentrated over a small area.
  • At higher latitudes, sun rays have to pass through more atmosphere so more heat energy is reflected or absorbed by the atmosphere and less heat is received by the Earth's surface
    At lower latitudes, sun rays have to pass through less atmosphere so less heat energy is reflected or absorbed and more heat is received by the Earth's surface.

With clouds

During the day 🌄, clouds reflect a large portion of the sun's shortwave radiation back to space, so the Earth's surface absorbs less heat and temperatures are lower during the day.


During the night 🌃, clouds reflect some of the longwave radiation emitted by the Earth's surface back to the Earth, preventing it from escaping into space and temperatures are higher during the night.

Without clouds

During the day 🌄, absence of clouds allows the sun's shortwave radiation** to reach the Earth's surface, allowing the Earth's surface to absorb more heat.


During the night 🌃, absence of clouds allows the longwave radiation emitted by the Earth's surface to escape into space, so the Earth's surface is cooler at night.

The Earth absorbs shortwave radiation from the sun, is heated up and then emits longwave radiation.

Higher altitudes mean greater distance from the source of longwave radiation and less heating by the processes of conduction and convection

Furthermore, air at higher altitudes is less dense and less able to absorb heat from longwave radiation so temperatures are lower

Maritime effect

  • During ☀, large ocean bodies heat up at a slower rate than land, the air over the sea is cooler than the air over land.
  • Cooler air over the sea lowers the temperature of coastal areas
  • During 🎄:, air over the sea cools down at a slower rate than land so the air over the sea is warmer than the air over land.
  • Warmer air over the sea increases the temperature of coastal areas

Smaller annual temperature range

Annual Temperature Range

Mean Annual Temperatures

Annual Temperature Range
Mean Annual Temperatures

Diurnal Temperature Range

Large annual temperature range of 21ºC

Evenly distributed rainfall but low total annual rainfall at 300mm

Vancouver, Canada

High mean annual temperature but lower than equatorial climates

Small annual temperature range of 3 to 4ºC

High total annual rainfall of over 2000mm, with no distinct wet or dry seasons

Distinct wet and dry seasons

Small annual temperature range of 2ºC

High mean annual temperatures of about 27ºC

Temperature

Annual temperature range

Mean annual temperature

Mean monthly temperature

Diurnal temperature range

Mean daily temperature

Rainfall

Total annual precipitation

Monthly precipitation

Even/Uneven Distribution

Bangladesh

Singapore

  • During periods of intense solar magnetic activity on the ☀, the number of sunspots increases
  • Sunspots are cooler regions on the Sun's surface that appear as dark spots. Areas around the sunspots radiate more heat energy.
  • Hence, increase in sunspots results in higher global temp.
  • During 🌋 eruptions, large volumes of sulphur dioxide, dust and ash are released into the atmosphere.

Number of sunspots rises and falls with an approiximate 11 year cycle.

  • Sulphur dioxide reacts with water to form sulphur-based particles in the atmosphere
  • The sulphur-based particles, together with dust and ash particles reflect solar energy from the Sun back into space.

Eruption of Mount Pinatubo 🌋 in 1991


  • 17 million tonnes of sulphur dioxide released into the atmosphere
  • Lowered temperatures in the ❤northern hemisphere❤ by as much as 0.6ºC

Effects are not long term
Human activities more impactful

Forests absorb greenhouse gases during photosynthesis, taking in a significant amount of global greenhouse gas emissions.

When trees are cut down, less trees are around to absorb carbon dioxide. Process of deforestation and land clearance also releases carbon dioxide.

Soil is a large carbon source as decay of organic matter causes carbon to accumulate in the soil. Deforestation exposes the soil to sunlight, which increases soil temperature and speeds up the rate of carbon oxidation in the soil, whereby carbon reacts with oxygen to produce carbon dioxide

Fossil Fuel carbon emissions

Meet energy demands of agriculture, industries and urbanising society

Agriculture

Global carbon emissions 🏭 totalled 30.6 billion tonnes in 2010 an 5.6% increase from 2009

Cows 🐄 release methane, a greenhouse gas as a waste product

Tractors run on fossil fuels which release carbon dioxide into the atmosphere

Inorganic fertilisers increases nitrous oxide in the soil, which is released when soil is toiled or when rain pours.

Industries

Manufacturing is an industrial activity that releases carbon dioxide as a by-product .

Maunfacturing a mobile phone: 60kg of carbon dioxide
Maunfacturing a computer: 275kg of carbon dioxide

Urbanisation

Fossil fuels are burnt to provide energy for household activities 🏘 in urban areas, such as cooking, heating and cooling.

Exhaust fumes released by high concentrations of transportation 🚃 in urban areas also contain greenhouse gases

Mosquitoes thrive, which results in the spread of dengue fever and malaria, infectious-insect-borne diseases. Regions with moderate temperatures such as Europe and North America now deal with diseases thought to only exist in the tropics.

Climate change can increase temperatures and rainfall around the world, which allow insects to thrive.

Causes significant economic losses and loss of lives

Eg. In August 2003, Europe experienced a heat wave that killed over 70000 people

Higher temperatures have resulted in greater amounts of water vapour and latent heat energy in the atmosphere.

Higher temperatures cause glaciers in Greenland and Antarctica to melt. Meltwater then causes a rise in the sea level

Higher temperatures cause water in the seas to expand in volume and causes sea level to increase

Causes loss of land and homes, especially at low-lying areas and islands

Eg. Over 600 million people worldwide live in areas less than 10 metres above sea level.

Majuro Atoll in the Pacific Ocean will lose 80% of its land if the sea level rises by half a metre

Changing growing seasons of crops

Higher temperatures in certain regions can result in longer growing seasons for some countries while causing a shorter growing season in other countries

More crops, such as blackberries 🍇 and maize 🌽 can be cultivated in the United Kingdom.

Production of fruits like apples and cherries, as well as nuts such as almonds and walnuts have decreased in the Yunnan province of China

International Agreements

Kyoto Protocol

Came into force on 16 February 2005

Placed responsibility to reduce greenhouse gas emissions on 37 developed countries, to reduce their combined greenhouse emissions by at least 5% below their 1990 levels

Successes

Many countries met and exceeded the carbon emission targets set by the protocol, such as Finland, Ireland and Greece

Encouraged sustainable development

The Clean Development Mechanism (CDM) used Certified Emission Reduction (CER) credits as incentives for developed countries to carry out emission-reduction projects in less-developed countries. One CER credit permits the country to release one tonne of carbon dioxide. This allowed less developed countries to benefit greatly

Limitations

Countries like Spain, Austria and Denmark did not meet their emission targets

Countries like the USA and China, two of the largest contributors to global warming did not sign the Protocol and continue to release large amounts of greenhouse gas in the atmosphere.

National Responses

Singapore Green Plan 2012

Launched by the Ministry of the Environment to shift Singapore energy source from fossil fuels to natural gas, aiming for 60% of Singapore's energy demands to be met by natural gas by 2012

Success

79% of Singapore's electricity was being generated by natural gas by as early as 2010

Limitations

Requires complex treatment plants to process the natural gas

Pipelines required to transport natural gas

Require expensive maintainence because they are laid underground and need to be inspected regularly for leaks

Plant-A-Tree programme

Launched by the Garden City Fund and the Singapore Environment Council to encourage citizens to donate money to buy trees or participate in monthly tree planting events around Singapore

Success

60000 trees are planted annually around Singapore by the National Parks Board (NParks)

Trees take many years to fully mature. Even fast-growing trees like angsana, rain trees and yellow flames take around 25 years to reach their full height

Greenhouse emissions have risen by 35% since 1997

Temperature decreases by 6.5ºC for every 1000m increase in altitude

  1. Coriolis Effect
    The Coriolis effect deflects the monsoon winds to the left in the southern hemisphere, forming the southeast monsoon winds
  1. Coriolis Effect
    After winds cross the Equator, the Coriolis effect deflects the monsoon winds to the right in the northern hemisphere