The Greenhouse Effects

The sunlight that arrives at the top of the atmosphere is referred to as ________________________ by atmospheric scientists.

Insolation

Visible light’s wavelength

~380nm to ~740nm

Infared

Heat

UV Light

Sunburn

This type of radiation makes up the largest range of wavelengths in sunlight

Infared

True or False? Hot springs, geysers, and volcanic eruptions have a significant direct effect on the heat content of our atmosphere.

False

The highest intensity of solar radiation is reached in this range of wavelengths

Visible light

A beam of solar radiation moves through an atmospheric gas molecule completely unimpeded and hits the Earth's surface. The beam is said to have been ____________________

Transmitted

A beam of sunlight hits an atmospheric gas molecule and the radiation splits, sending some rays back to space, and others towards the surface. The beam of sunlight is said to have been__________________

Scattered

The following three gases make up 99.9% of the air in the Earth's atmosphere (click all that apply)

Nitrogen, oxygen, argon

Although some aerosols are able to absorb heat for short periods of time, the main role aerosols play in the greenhouse effect is as

Reflectors

In general, greenhouse gases are collectively most effective at absorbing which wavelengths?

Infared

Which greenhouse gas effectively absorbs the greatest range of sunlight's wavelengths?

Water vapor

Carbon dioxide effectively absorbs the following wavelengths?

wavelengths between approximately 14 and 19 microns

Wavelengths between 0.3 and 2.3 microns are collectively known as......

wavelengths that make up the "window of incoming solar radiation"

When it comes to insolation, three important numbers are 30%, 47%, and 23%. What do they measure?

30% of insolation is reflected 23% of insolation is absorbed by the atmosphere 47% of insolation is absorbed by the Earth's surface

On average, most reflection of insolation takes place....

at the top of the atmosphere

On average, most of insolation is___________________

transmitted through to the surface of the Earth

The albedo of a surface is a measure of its reflectivity. Which of the following surface has a low albedo and therefore ABSORBS most of the insolation.

Water

Asphalt and water share almost the same albedo (5-6%). In other words, they absorb roughly the same amount of insolation and reflect only very little insolation. Yet, after a day in the hot sun, asphalt gets really hot, whereas a similarly thick layer of water does not. Why?

asphalt has a lower heat capacity than water - its temperature rapidly rises with increased heat absorption, whereas that of water does not.

True or False? UV radiation that is absorbed by the Earth's surface is, in part, reradiated back to the atmosphere as UV radiation.

False

Insolation that is reflected by the surface of the Earth essentially travels out through the atmosphere back to space without being absorbed by the atmosphere. Why?

All insolation that reaches the Earth's surface has already been "stripped" of most of the wavelengths readily absorbed by atmmospheric gas molecules, so the outgoing reflected insolation is essentially invisible to gas molecules

Heat absorbed by water molecules causes them to turn into a gaseous phase and rise into atmosphere

Evaporation

Some of the Earth's absorbed heat is directly transferred to air molecules in contact with the surface

Conduction

Heat emitted from the Earth's surface in the form of wave energy

Radiation

Heat emitted by atmospheric gas molecules (after they absorbed it) is solely in the __________________ range of the spectrum

Infared

Historically, the atmosphere has lost the same amount of heat that it also gained at any moment in time. This is called heat equilibrium. Why then has the atmosphere not stayed freezing cold?

because after the last Ice Age, the Earth reached a certain stable level of greenhouse gases in its atmosphere. Until about 1750, these gases were at full heat capacity. Any heat added to them, would also immediately be lost to space, however, they always hold on to heat in the process.

The radiation absorbed by the Earth's heat is effectively converted into.......

longer wavelengths, notably long-wave infrared

The Earth of today gains on average around 0.87 Watts of heat per square meter MORE than it is losing back to space. This observable and measurable phenomenon is known as.....

Global warming

There are ____ major greenhouse gases, responsible for absorbing and trapping heat in our atmosphere.

6

What are the 6 major GHG?

Methane, nitrous oxide, oxygen, ozone, carbon dioxide, water vapor

Which of the following gases most effectively absorb incoming solar radiation in the UV range of the spectrum? (Look at the graph labelled "Absorption of Radiation by Atmospheric Gases" in your lecture slides)

ozone and oxygen

On average, most of insolation is___________________

transmitted through to the surface of the Earth

Which of the following gases most effectively absorb infrared wavelength of around 10 microns?

Oxygen and ozone