The Sun and The Earth’s Climate System
Feb 23, 2016
The Sun and The Earth’s Climate
System
The Global Climate System
Consists of:1. Water2. Air (Atmosphere)3. Land4. Living Things
How the Sun Affects Global Climate
SystemSolar Energy: the Earth's climate is powered by energy from the sun. different regions on Earth receive different amounts of
solar energyFactors that affect the amount of solar radiation: Latitude - closer to the equator receives direct solar
energy and as you move toward the poles the solar energy becomes more spread out
Earth's tilt - on an angle such that part of one hemisphere is a further distance from the sun than another at one time
Latitude & Solar Energy
Since the Sun hits higher latitudes at an angle, the radiation must pass through more of the atmosphere.
Thus, more energy is absorbed and reflected by the atmosphere, and less will reach the ground.
= lower temperatures
Solar Energy: Absorbed & Reflected
When solar radiation enters our atmosphere three things can happen, it can be absorbed, reflected or transmitted
What happens to the solar energy?
30% reflected back to space by clouds and particles in the atmosphere
70% transmitted and absorbed by the Earth's surface and clouds
the energy that is absorbed is either used by plants for photosynthesis or absorbed by rocks, soil and water causing them to heat up and heat the air around them
Energy absorbed by Earth and atmosphere
Energy radiated back again by Earth and atmosphere
=
As a result of this balance of energy, Earth’s global temperature stays fairly constant.
The Climate SystemBalance is maintained by:4 Main Components
1. Water (Hydrosphere)2. Air (Atmosphere)3. Land (Lithosphere)4. Living Things (Biosphere)
Atmosphere The layers of gases surrounding Earth Near Earth’s surface, the atmosphere consists
mainly of nitrogen (78%), oxygen (21%), and small amounts of other gases, such as argon, carbon dioxide, and water vapour.
Acts like a blanket conserving thermal energy Also protects Earth from dangerous radiation The atmosphere consists of several layers,
each with distinct properties:
Layers of the Atmosphere
1. Troposphere contains 75% of all the air in the atmosphere, and almost all of the water vapour (which forms clouds and rain). - Weather occurs in this layer
2. Stratosphere referred to as the “ozone layer”. Ozone protects us by absorbing the harmful ultraviolet (UV) radiation from the Sun.
3. Mesosphere, the middle layer. This layer contains the lowest density of gases and temperature.
4. Thermosphere is the hottest layer Produces a beautiful light called the aurora – more commonly referred to as the Northern and Southern Lights.
5. Exosphere is the beginning of “space”.
Ozone in the Stratosphere
Ozone prevents most of the harmful energy from reaching us It absorbs high-energy UV radiation from the sun UV radiation damages plants and causes cancer in animals and people In 1970’s the ozone layer was thinning over Antarctica In 1990’s an ‘hole’ began to form over the Arctic region Ozone depletion is causes by man-made chlorofluorocarbons (CFCs)
which were used in pressurized spray cans, refrigerators and air conditioners.
When released, they can travel up to the stratosphere, react with the ozone and destroy it
In 1987, the use and production of CFCs was banned (Montreal Protocol) Ozone layer is starting to recover, but will take about 50 years to get
back to its original thickness
Ozone in the Troposphere
UV radiation from Sun and exhaust from cars combine to produce ground level ozone
This toxic mixture of gases and particles is called photochemical smog
Photochemical smog harms human health, damages buildings and affects plants and animals
Ontario has introduced the Drive Clean program to reduce smog-causing emissions produced by cars
The Hydrosphere The hydrosphere includes all of Earth’s
water, both fresh and salt, liquid and ice. It makes up around 70% of Earth’s surface.
THE WATER CYCLE Our weather systems depend greatly on
water in its three states: solid, liquid, and gas or vapour.
Evaporation absorbs energy and cools the surroundings; condensation gives off energy and warms the surroundings.
Water & Climate Zones
Water absorbs and stores more thermal energy than land
Water heats up and cools down more slowly than land
Regions near large bodies of water tend to be cooler in summer and warmer in winter than inland regions
Regions downwind tend to get more snowfall, because air passing over the water absorbs more water vapour, which condenses to form snow when it reaches the colder land
Ice & Climate System 2% of Earth’s water is frozen, most located at the poles Sea ice (pack ice) is relatively thin ice formed from
frozen sea water, floats in the water Ice sheets are areas of permanent ice spread out
overland and are several kilometres thick Permanent ice is also found in glaciers, on
mountaintops and the permafrost Icebergs are large pieces of glaciers that have broken
off and float in the ocean Ice and snow reflect more radiant energy than rocks
and vegetation
Ice - Albedo Affect
Albedo is a measure of the reflectivity of a surface. The albedo effect when applied to the Earth is a measure of how much of the Sun's energy is reflected back into space. Overall, the Earth's albedo has a cooling effect.
Albedo Affect -Altered
Low level clouds are often thick and reflect much of the incoming shortwave radiation. Because of their low altitude they emit large amounts of longwave radiation into space. High clouds tend to have a net warming effect as they because of their high altitude and resulting low temperature only emit little longwave radiation towards space and reflect little of the incoming shortwave radiation.
Lithosphere Is the earth’s crust Includes solid rock, soil and minerals on
land under the oceans It absorbs higher-energy radiation from
the Sun and converts it into thermal energy, then emits the energy back as lower-energy (Infrared radiation)
Land Formations & Climate Zones
Mountains force air to rise up on the windward side resulting in precipitation as it rises, then on the leeward side there is little rain
This process is called the rain shadow effect At high altitudes, atmospheric pressure is
lower because there is less air pushing down Air is cooler at higher altitudes forming an
‘alpine climate’, which greatly affects the ecosystems located there
Living Things - Biosphere
Plants and animals are involved in change of gases in the atmosphere
Plants undergo photosynthesis Plants and animals undergo cellular respiration Some animals (cows, sheep) and termites produce
methane gas Carbon dioxide and methane absorb infrared
radiation emitted by Earth, the amount of these gases will affect the amount of radiation the atmosphere can absorb; which can affect the Earth’s climate