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What you should know by the end of this lesson:
What you should know by the end of this lesson:
What the Global heat budget is
Have a good understanding of the effects on the solar insolation
What is the Global Heat Budget?
What is the Global Heat Budget?
The amount of heat that the earth absorbs and the amount of heat that escapes (as radiation) is exactly the same. This is known as the Global Heat Budget.
The Albedo Affect
The Albedo Affect
The composition or make-up of the atmosphere does vary from place to place and at different times of the year. However, the 4 main gasses tend to remain fairly stable throughout the atmosphere.
Digital Workbook and Paper Jotter
Take a copy of the Definition of Albedo
Copy and complete the table - fill in the blanks with a guess of what you think the albedo of the surface would be.
Check your answers in the drop-down box.
Albedo: a measure of how much light hits a surface is reflected without being absorbed.
Albedo is measured on a scale of 0 to 1:
0 showing no reflectivity and 1 showing that all light energy is reflected.
The Albedo Affect
The Albedo Affect
You may have already come across the albedo effect. It refers to the properties of dark surfaces to absorb more energy and light surfaces to reflect more light.
Check your answers
Check your answers
Cumulonimbus Clouds - 0.9
Dark Soil - 0.1
Fresh Snow - 0.85
The average albedo for Earth is 0.31
A quick reminder...
A quick reminder...
Greenhouse Effect – Reminder!!!
Greenhouse gases interfere mainly with longwave radiation given off by the earth.
Examples include:
Water Vapour (H2O)
Carbon Dioxide (CO2)
Methane (CH4)
Nitrous Oxide (N2O)
Ozone (O3)
Without them, the earth would be 33oc colder.
The Global Heat Budget?
The Global Heat Budget?
The earth receives incoming energy from the sun (insolation). Only 51% of this is absorbed by the land & ocean surfaces. The Global Heat budget explains what happens to all of the solar insolation.
You can watch me discuss this diagram in full in the YouTube Video above.
Digital Workbook and Paper Jotter
Create your own copy of the Global Heat Budget Diagram
Add Annotations for extra explanation to each section
Extra
A common question in Higher is:
Explain why the Earth’s surface absorbs only 51% of the solar energy received at the edge of the atmosphere.
You should refer to both conditions in the Earth’s atmosphere and at the Earth’s surface. (8)
Assess your answer to see if it would be good enough to be an 8 mark answer
Question Answer
Question Answer
The albedo effect is a measure of how much light is reflected or absorbed by the surface of an object (1). The reflection and scattering of solar radiation and reduces the amount of solar energy absorbed by the surface of the earth by about 49% (1)
Approximately 20% is reflected by clouds (1), and 6% is scattered by gas particles in the air (1).
Lighter surfaces reflect more of the incoming radiation (1)—this accounts for approximately 4% reflected from the Earth’s surface (1).
Reflection varies dependent on cloud cover, more cloud cover will mean more cloud reflection (1) and also the covering at the earth’s surface, as darker equatorial forest surfaces absorb more incoming radiation than polar ice caps (1)
Absorption by the atmosphere reduces the solar energy by 20% - through clouds (3%) (1) and by dust, water vapour and other gases (approx. 17%) (1).
Check your Learning
Check your Learning
Lesson Complete
Lesson Complete
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