// lecture 05 Flashcards

1
Q

factors that influence climate at a given place:

A

sunshine (and latitude), topography/mountains, proximity to oceans and large lakes, ocean currents, presence of trees/vegetation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

energy from the sun is

A

electromagnetic radiation. goes through space at the speed of light. either absorbed or reflected once it gets to earth.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

radiation with shorter wavelengths are

A

more energetic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

shortest wavelength to longest wavelength:

A

gamma rays, x-rays, ultraviolet (UV) radiation, visible light, infrared radiation, microwaves, and radiowaves.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

the sun emits:

A
  • visible light.
  • near infrared radiation (infrared with very short wavelength, but longer than visible).
  • small, but dangerous, amount of ultraviolet radiation.

these three bands together are called “shortwave radiation” or “solar radiation.”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

insolation

A

the amount of solar radiation energy coming in.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

by the time it gets to the top of the atmosphere, the sun shines at a strength of

A

1360 watts per square meter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

1360 W/m^2 is roughly what’s experienced in the

A

tropics when the sun is directly overhead.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

if the area is perpendicular to the solar beam,

A

then the solar energy per unit area is maximized.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

solar x exposure area

A

sweat x skin area.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

the average incoming solar radiation is

A

340 W/m^2, which is exactly 1/4 of 1,360 W/m^2.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

high latitudes get less

A

direct radiation, which spreads out more.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

shadow area of a sphere (a circle) is

A

1/4 of the surface area of a sphere 4pir^2. shadow area = pir^2.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

only ___ of solar radiation gets absorbed in the ____

A

20%, atmosphere; 50%, surface; and 30%, reflected back to space.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

albedo

A

fraction of incident light that’s reflected away. ranges from 0 (no reflection) to 1 (all gets reflected).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

human eye sensitivity is most to

A

wavelengths around 550 nanometers. when light levels are low, it shifts to around 500 nanometers.

17
Q

solar emission peaks in the

A

blue region of visible radiation, which is a big part of the solar emission.

18
Q

near infrared also constitues an

A

important energy flux.

19
Q

albedo values for earth:

A
  • cloud albedo varies from 0.2 to 0.7. thicker clouds have higher albedo.
  • snow albedo ranges from 0.4 - 0.9 (depends on age) and ice is about 0.4.
  • ocean is < 0.1, forests are 0.15, and deserts are 0.3.
20
Q

30% of incoming solar radiation is reflected away by:

A

15% from clouds, 8% from the surface, and 7% by the atmosphere (things like dust from deserts and air pollution are key).

21
Q

Earth Radiation Budget Experiment

A

measured Earth’s albedo from a system of orbiting satellites.

22
Q

total absorbed solar radiation is

A

70% of the incoming solar radiation because 30% is reflected away. 70% of 340 W/m^2 = 240 W/m^2.

23
Q

earth loses energy through

A

infrared radiation (longwave radiation)

24
Q

everything emits radiation, which depends

A

partly on the substance, but mostly on temperature.

25
thermal night vision technology
detects longwave radiation.
26
higher temperature =
more radiation and more energetic radiation (shorter wavelength).
27
the earth is heated by tje
sun (shortwave radiation) and it loses energy by longwave radiation (out to space).
28
if the energy (solar radiation) into a system (Earth) is greater than
the energy out (outgoing longwave radiation), the temperature will increase, which results in an increase of energy out (longwave radiation). this will happen until E in = E out (energy balance).
29
global warming...
upsets the energy balance of the planet.
30
if there was no atmosphere for energy balance to occur,
the mean temperature of the earth would be -18 C.
31
greenhouse effect:
all longwave radiation doesn't escape directly to space.
32
Stefan-Boltzmann law
- a body emits as the fourth power of its temperature in Kelvins. - Kelvin is the absolute temperature scale 0 C = 273 K. - the hotter an object, the more radiation it emits: blackbody emission = sigma T^4 where sigma = 5.67 x 10^-8 W m^-2 K^-4. - the basic way earth stabilizes its temperature is by getting hotter and emitting more energy to space.
33
the temperature of a black body that emits the same amount of longwave radiation that the earth needs to emit to balance its absorbed solar radiation
absorbed solar radiation = emitted longwave radiation 5/4(1 - albedo) = sigma T^4.
34
greenhouse gases block longwave radiation from
escaping directly back to space. these gases re-radiate both upward and downward. the extra radiation causes additional warming of the surface.
35
greenhouses gases cause the
outgoing radiation to happen at higher levels (no longer at the surface). air gets colder as you go upward, so the radiation space is much less (colder -> less emission).
36
atmosphere and surface are black bodies for
terrestrial. atmosphere is transparent to solar.