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What is Albedo

• The ability to reflect solar energy is referred to as albedo.

• Rough textured, irregular, and dark-colored materials have a low albedo, making them good absorbers of solar radiation.

• Uniform and light-colored materials such as snow, water at low sun angles, and sandy soils have a higher albedo and reflect more solar radiation, thus absorbing less energy.


Which surfaces will have the highest albedo values?


How does sun affect temperatures at different latitudes?.

Effect of axial tilt on incoming solar radiation

Sun angle determines the intensity of energy.


What Determines Seasons?


What is the atmosphere?

The atmosphere is divided into five major layers.

The Earth is different than the other planets in our solar system because it has an atmosphere that can support life.

The atmosphere is an envelope of different gases (air) surrounding Earth.

These layers are divided based on temperature.

troposphere

stratosphere

mesosphere

thermosphere

exosphere


What is the atmosphere made of?

The gases that make up the atmosphere are:

about 78% is nitrogen

about 21% is oxygen

the remaining 1% is mostly argon (0.93%) with some carbon dioxide (0.035%), varying amounts of water vapor and

trace amounts

of other gases


Why is the atmosphere important?

Although each layer of the atmosphere has unique properties, all layers are necessary to sustain life on Earth.

The atmosphere protects our planet’s surface from harmful radiation. It also retains some of the Sun’s heat, keeping Earth warm enough for life to exist.


Air pressure and the troposphere

80% of atmospheric gases are in the troposphere: the 15 km of the atmosphere closest to Earth. This is a very thin layer compared to the Earth’s diameter, which is 12,756 kilometers.

Atmospheric gases are made up of tiny particles, each of which exerts pressure in all directions. Higher up in the atmosphere, there are fewer particles, which causes a decrease in air pressure.

Nearly all weather takes place in the troposphere.


Name the layer of the atmosphere that matches each description:

• commercial jets fly here

• weather occurs here

• extends to a height of about 10 km (6.2 miles)

• two layers with steadily increasing temperatures

• contains a layer of ozone to absorb ultraviolet radiation

• meteors are typically burned up in this layer


Name the layer of the atmosphere that matches each description:

– begins about 500 km (310 miles) above Earth – meteors occur here– satellites are found here and converge into interplanetary space– extends for 10 to 45 km (28 miles) above Earth’s

surface– in these two layers, the temperature decrease steadily

with increasing altitude

-- layer with the lowest air pressure

-- layer with the highest air pressure

-- aurora occurs here


What is heat transfer?

Heat is transferred by three main processes:

conduction

convection

radiation

Energy reaching Earth drives global interaction between the atmosphere and the surface, creating wind and influencing ocean currents.

The Sun is the external source of energy for Earth.


Conduction, convection and radiation

Convection is the transfer of heat energy by the movement of matter. For example, in a saucepan on the stove there is a steady flow between the warm and cool sections of a fluid. This is a convection current.

Conduction is the transfer of heat energy by direct contact, or from particle to particle. For example, a spoon in a bowl of soup becomes warmer because the heat from the soup is conducted along the spoon.

Radiation is the transfer of heat energy by electromagnetic radiation. For example, energy from the Sun travels to Earth by electromagnetic waves.


Identifying heat transfer


Differential heating

Radiation from the Sun does not hit Earth everywhere at the same time and in equal amounts.

Many factors, such as altitude and latitude, affect the amount of radiation reaching an area.

This means that some places receive more heat while others receive less heat. This is known as differential heating.


Wind currents


Coriolis effect


Global wind currents

The global pattern of wind currents can be shown by the three cell model of air circulation. This shows:

convection cells (formed due to differences in high and low pressure)

deflected winds (due to the Coriolis effect)

This forms three main wind patterns in each hemisphere.

polar easterlies

westerlies

trade winds

westerlies

polar easterlies


Climate zones

Wind circulation patterns, along with other factors, contribute to the location of different climate zones.

Convection cells at the equator, called Hadley cells, create areas of high and low pressure associated with the trade winds. Low pressure at the equator results in high rainfall – forming Africa’s equatorial rainforests.

High pressure areas occur around 30° north and 30° south latitudes. These areas see very low annual rainfall – forming the arid land of the Sahara and Kalahari deserts.

equator


True or false?


Microclimates


What Creates Microclimates?

• Topographya. mountains

b. different amounts of solar radiation

north vs. south, east vs. west

c. vegetation

1. takes up and releases water

2. changes the movement of wind near the

ground

3. cast shadows ( open land vs. forest)


• Cities– Building materials absorb and hold heat– Building block wind flow– Motor vehicles and air conditioners release

heat and pollutants


Rain Shadow Effect


surface currents

deep currents

Ocean currents

Heating of the Earth's surface and atmosphere by the Sun also drives convection within the oceans, producing ocean currents.

surface currents – this occurs in the upper part of the ocean. This involves just the top 10% of the water in the ocean.

There are two circulation systems in the ocean:

deep currents – this occurs below 400 meter depth.

400 m


Surface circulation


Ocean water density

The density of ocean water varies due to differences in temperature and salinity. The dark blue areas show the regions of higher density.


Thermohaline circulation

Water at the poles is very cold and ice formation causes the water to become salty. This dense water sinks, starting a deep current that moves water throughout the world’s oceans.

This is often called the global ocean conveyor belt.


How much do you know?


Surface Ocean Currents

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