Midterm

Question 1

Why doesn’t gravity collapse the atmosphere?

Answer 1

Pressure Gradient Force

Question 2

How does PGF function?

Answer 2

Exerted upwards by atmosphere which balances gravity / air is directed from high pressure to low pressure

Question 3

How are molecules attracted to Earth’s surface?

Answer 3

Gravitational Force

Question 4

Force Equation

Answer 4

Mass x acceleration

Question 5

What is pressure?

Answer 5

Force over a given area

Question 6

How does the vertical profile of atmo behave?

Answer 6

Pressure decreases with altitude in the atmo.

Question 7

What is hydrostatic balance?

Answer 7

The balance between the downward gravitational force and the upward PGF

Question 8

Pressure equation

Answer 8

force/area

Question 9

What does isothermal atmosphere assumption mean?

Answer 9

constant temperature of entire atmosphere

Question 10

What is the solar luminosity value?

Answer 10

3.87 x 10^26

Question 11

What is the solar constant?

Answer 11

1368

Question 12

Solar luminosity definition

Answer 12

the total rate of energy released by the sun

Question 13

How do we find solar constant?

Answer 13

using mean distance between Earth and the sun, we get a constant solar irradiance value

Question 14

How do we use solar constant?

Answer 14

Represents the annual average solar irradiance value

Question 15

How does Earth maintain a constant temperature?

Answer 15

Energy In = Energy out

Question 16

If the energies do no equal what happens?

Answer 16

Earth’s temperature changes

Question 17

What does disk Earth do?

Answer 17

receives solar radiation over the area of the disk

Question 18

What does sphere Earth do?

Answer 18

Emits radiation over the surface area of a sphere

Question 19

What is the emission temperature of Earth?

Answer 19

255K

Question 20

How is most of radiation emitted?

Answer 20

Most are emitted to space via the atmosphere, not the surface (to maintain energy balance)

Question 21

Zero dimensional energy balance model?

Answer 21

Transparent atmosphere, the surface temperature would equal the emission temperature

Question 22

Single-layer atmosphere model

Answer 22

Assuming that the atmo is completely transparent to incoming radiation and completely opaque to outgoing radiation

Question 23

What does the single-layer atmo model show?

Answer 23

The surface temp increases by a factor of 2 and 1/4 times the emission temperature.

Question 24

What are “Atmospheric Windows”?

Answer 24

Places where energy passes through to space

Question 25

What is Planck's Law of blackbody emission?

Answer 25

Emission from a blackbody has a characteristic frequency distribution that depends on the object's temperature.

Question 26

What kind of wavelength does the Earth emit?

Answer 26

Longwave

Question 27

What kind of wavelength does the Sun emit?

Answer 27

Shortwave, can pass through the atmosphere without being absorbed (scattered)

Question 28

Why is a greenhouse gas a greenhouse gas?

Answer 28

Dipole molecular makeup

Question 29

How are they able to absorb?

Answer 29

By rotating and vibrating

Question 30

How do greenhouse gases interact with electromagnetic radiation?

Answer 30

molecular vibration and rotation

Question 31

How does the molecule vibrate?

Answer 31

Dipole moment, causes it to vibrate and then absorb the radiation as kinetic energy

Question 32

Why is is CO2 still able to be a greenhouse gas?

Answer 32

Even though it is not a dipole, the double polar bonds can cause it to become asymmetric and then vibrate.

Question 33

Can CO2 absorb via rotation?

Answer 33

No, rotation does not induce a dipole moment

Question 34

What does the blue jagged line on MODTRAN show?

Answer 34

The intensity of radiation at different wavelengths coming from the Earth/atmosphere that reaches the satellite

Question 35

Why does the blue line not follow theoretical black body curve?

Answer 35

atmosphere emits energy at different frequencies, lower intensity because the atmosphere is colder

Question 36

What are absorption bands?

Answer 36

when energy is remitted at a colder temperature (example CO2 window)

Question 37

Why do gases absorb different wavelengths of infared energy?

Answer 37

Each gas molecule has different vibrational and rotational frequencies

Question 38

What does a temperature profile tell us about IR radiation absoption?

Answer 38

radiation at wavelenghts is emitted to space from the top of the troposphere due to the cold temperatures

Question 39

What is band saturation?

Answer 39

complete absoption of radiation at a specific wavelength band

Question 40

When adding CO2, why does the window widen?

Answer 40

Broadening

Question 41

Doppler broadening

Answer 41

Movement of molecules relative to photons allows a broader range of frequencies of radiation to interact with the molecule

Question 42

Pressure broadening

Answer 42

Collisions between molecules transfer energy during radiative transitions, allowing photons with a broader range of frequencies to interact with the molecule

Question 43

Where is pressure broadening most important?

Answer 43

Lower atmosphere

Question 44

How does the greenhouse effect flow?

Answer 44

Logarithmically

Question 45

Shortwave via clouds

Answer 45

Cloud impacts on incoming solar radiation

Question 46

Longwave via clouds

Answer 46

Cloud impacts on outgoing longwave radiation

Question 47

Which cloud warms the climate?

Answer 47

High clouds

Question 48

Low Cloud emission temperature?

Answer 48

High

Question 49

High cloud emission temperature?

Answer 49

low

Question 50

Why does the low cloud have a high emission temperature?

Answer 50

it is closer to the surface, so the outgoing radiation from the surface versus the cloud will be similar