Climate Lecture 2- Global Energy Cascade

Question 1

What is the energy source for the global climate system?

Answer 1

sun

Question 2

What is solar energy equal to?

Answer 2

1 trillion 1 megaton Atomic bombs per second

Question 3

How far away is sun from earth?

Answer 3

around 150 million km

Question 4

What is energy flux density?

Answer 4

Energy flux density is amount of energy received over an area
1 w/m2
Where flux = flow and flux density = flow per unit area

Question 5

How is solar energy distributed?

Answer 5

Right angles to solar beam
Outside atmosphere

Question 6

What is flux density?

Answer 6

1370 wm-2 (or w/m2)

Question 7

What is the rate sun send energy at?

Answer 7

2.9 x 10 (26) w

Question 8

Name 3 types of shortwave radiation?

Answer 8

Gamma rays
x-rays
ultra violet

Question 9

Name 3 types of longwave radiation?

Answer 9

Infrared
Microwave
Radio

Question 10

What is the Stefan-Boltzmann Law?

Answer 10

The Stefan–Boltzmann law, also known as Stefan’s law, states that the total energy radiated per unit surface area of a black body per unit time (also known as the black-body irradiance or emissive power), E*, is directly proportional to the fourth power of the black body’s thermodynamic temperature
T (also called absolute temperature)

Question 11

Discuss infrared radiation.

Answer 11

Long wave, everything emits it

Question 12

Discuss ultraviolet radiation.

Answer 12

Try to avoid as can cause damage
shortwave

Question 13

What is wavelength associated with?

Answer 13

Temperature of the emitting object

Question 14

Is sun short or long wave?

Answer 14

Short as temp is 6000 degrees

Question 15

Is earth short or long wave?

Answer 15

Long

Question 16

What is Wein’s Law?

Answer 16

Wein’s Law describes the relationship between temperature (K) and the wavelength (m) associated with maximum energy output from a blackbody

Question 17

What is the constant in Wein’s Law equal to?

Answer 17

2897

Question 18

Discuss Wein’s Law in practie.

Answer 18

As Temperature (of blackbody) increases,
overall radiated energy increases
peak of radiation curve moves to shorter
wavelengths

Question 19

Can orbit influence radiation distribution?

Answer 19

Yes

Question 20

Is the maximum wavelength of the sun emitted in the visible range?

Answer 20

Yes

Question 21

What axis is Earth on?

Answer 21

23.5 degrees

Question 22

What influences seasons?

Answer 22

Tilt of the Earth

Question 23

When do the Solstice and equinoxes occur?

Answer 23

Autumnal equinox- Sept 22-23
Winter solstice- Dec 21-22
Vernal equinox- Mar 20-21
Summer solstice- Jun 20-22

Question 24

During an equinox does the Earth’s axis tilt towards or away from the sun?

Answer 24

No

Question 25

What is the sub-polar point?

Answer 25

The point of Earth's surface at right angles to the sun In the summer for NH this is in the Tropic of Cancer

Question 26

Is all daylight the same during an equinox?

Answer 26

Yes

Question 27

What are the three types of milankovitch cycle?

Answer 27

Precession (19, 22 and 24 kyr) Obliquity (41 kyr) Eccentricity (95, 125 and 400 kyr)

Question 28

Does a higher / low (closer to pole) have a greater or lesser day length?

Answer 28

Greater

Question 29

Does a higher / low (closer to pole) have a greater or lesser variation in insolation?

Answer 29

Greater

Question 30

Does sun angle affect intensity?

Answer 30

Yes, e.g. 45 degrees has 40% greater area but 30% less intensity than 90 degrees.

Question 31

What can happen to insolation?

Answer 31

Scattering, longwave emission or reflection

Question 32

Discuss what could happen with incoming longwave radiation.

Answer 32

100 units of incoming radiation- 6 units is reflected by atmosphere, 19 absorbed by atmosphere and clouds and 51 absorbed at surface, 20 reflected from clouds and 4 reflected from surface.

Question 33

What is direct SW?

Answer 33

Shortwave radiation which passes uninterrupted through the atmosphere

Question 34

What is diffuse SW?

Answer 34

SW which is scattered or reflected downwards, that is, has a partly interrupted path to the surface but in the end makes it to the surface.

Question 35

What is the symbol for net radiation?

Answer 35

Q*

Question 36

What does K* stand for?

Answer 36

New SW

Question 37

What does L* stand for?

Answer 37

Net LW

Question 38

What happens to energy at Earth's surface?

Answer 38

Energy at Earth's surface is dissipated by latent heat transfer (state change/evaporation) and sensible heat (flow of energy along a temperature gradient, can be measured with a thermometer)

Question 39

What do albedo control?

Answer 39

Outgoing SW Determines incident shortwave radiation available at the surface.

Question 40

Discuss typical albedo values.

Answer 40

Clouds- 30-90 Fresh snow- 75-95 Grass- 10-30

Question 41

Where is albedo highest?

Answer 41

In the poles

Question 42

Which areas have a deficit of heat energy?

Answer 42

Higher latitudes but surplus in equatorial and tropical regions.

Question 43

What can redistribute heat energy to offset deficits?

Answer 43

Atmospheric and oceanic circulation

Question 44

What is the energy balance equation?

Answer 44

Q* = H + LE + G Net radiation = sensible heat + latent heat + subsurface heat

Question 45

What is Bowen ratio?

Answer 45

H/LE Sensible heat / latent heat

Question 46

Discuss different Bowen ratios?

Answer 46

Deserts >10.0 Tropical rainforests 0.1-0.3 London 6.0-7.0

Question 47

Why do desert locations have less LE transfer?

Answer 47

Reduced water

Question 48

Discuss energy partitioning for moist surface - day.

Answer 48

Most of Q* goes into LE (evaporation) with little sensible heating of the atmosphere. Some heat flow into the soil (G)

Question 49

Discuss energy partitioning for moist surface - night.

Answer 49

Night there is no SW so Q* is negative because of LW increase (no SW decrease). Atmosphere is warmer and moister than the surface so H and LE directed to the surface. Surface is cooler than subsurface so G is directed to the surface

Question 50

Discuss energy partitioning for dry surface - day.

Answer 50

Most of Q* goes into sensible heating (H) of the atmosphere because little moisture for evaporation (LE) to proceed). Some heat flow (G) into the soil.

Question 51

What is urban energy balance similar to?

Answer 51

'Dry day'

Question 52

What is rural energy balance similar to?

Answer 52

'moist day'

Question 53

Discuss energy transfers in tropical climate.

Answer 53

The annual variation of net radiation shows a typical pattern of Q* being at a maximum during the summer and minimum during the winter. Latent heat transfer (LE) is high at West Palm Beach because of the water availability near the ocean. Latent energy transfer into the air is greatest during the summer time which is the wettest period of the year, and when net radiation is the highest. Warmer summer time air can hold more moisture and hence there is a larger moisture gradient to drive latent heat transfer. The annual variation of sensible heat transfer is determined by the available net radiation and the temperature gradient between the air and surface, as well as use of energy for latent heat transfer. During the spring a larger temperature gradient exists between the surface and the air above. Ample rainfall occurs during the summer providing water for evaporation. During this time period, sensible heat transfer decreases as net radiation is allocated to evaporation and latent heat transfer.

Question 54

Discuss energy transfers in a dry desert climate.

Answer 54

A warm and dry location typical of the mid-latitude desert climate. The most noticeable characteristic of this place is the lack of latent heat transfer. Though ample radiation is available here, there is little water to evaporate. Nearly all net radiation is used for sensible heat transfer which explains the hot, dry conditions at Yuma.

Question 55

What is net radiation a result of?

Answer 55

The balance between all energy inputs and outputs