Energy-Balance Essentials

Question 1

How dose earths energy budget work?

Answer 1

A budget in terms of energy is a balance sheet of energy income and expenditure. For Earth, energy income is insolation, and energy expenditure is radiation to space, with an overall balance maintained between the two.

Our Earth–atmosphere energy budget comprises shortwave radiation inputs (ultraviolet light, visible light, and near-infrared wavelengths) and longwave radiation outputs (thermal infrared wavelengths) that pass through the atmosphere by transmission.

Question 2

What is Transmission?

Answer 2

Transmission refers to the uninterrupted passage of shortwave and longwave energy through either the atmosphere or water.

Question 3

What is the definition of energy (For the purpose of studying earths energy)

Answer 3

For the purpose of studying Earth’s energy budget, energy can be defined as the capacity to do work, or move matter. (Matter is mass that assumes a physical shape and occupies space.)

Question 4

What is kinetic energy

Answer 4

Kinetic energy is the energy of motion, produced when you run, walk, or ride a bicycle, and produced by the vibrational energy of molecules that we measure as temperature

Question 5

What is potential energy?

Answer 5

Potential energy is stored energy (stored either due to composition or position) that has the capacity to do work under the right conditions. Petroleum has potential energy that is released when gasoline is burned in a car’s engine. The water in the reservoir above a hydropower dam has potential energy that is released when the pull of gravity impels it through the turbines and into the river downstream. (Potential energy is converted into kinetic energy in both these examples.)

Question 6

What is Heat

Answer 6

heat is the flow of kinetic energy between molecules and from one body or substance to another resulting from a temperature difference between them. Heat always flows from an area of higher temperature into an area of lower temperature

Question 7

What is Sensible heat

Answer 7

Heat that can be measured with a thermometer; a measure of the concentration of kinetic energy from molecular motion. Sensible heat can be “sensed” by humans as temperature, because it comes from the kinetic energy of molecular motion

Question 8

What is latent heat?

Answer 8

Latent heat (“hidden” heat) is the energy gained or lost when a substance changes from one state to another, such as from water vapour to liquid water (gas to liquid) or from water to ice (liquid to solid). Latent heat transfer differs from sensible heat transfer in that as long as a physical change in state is taking place, the substance itself does not change temperature

Question 9

What is Radiation heat?

Answer 9

Heat energy can be transferred in a number of ways throughout Earth’s atmosphere, land, and water bodies. Radiation is the transfer of heat in electromagnetic waves, such as that from the Sun to Earth, discussed in Chapter 2, or as from a fire or a burner on the stove (Figure 4.2). The temperature of the object or substance determines the wavelength of radiation it emits (we saw this when comparing Sun and Earth in Chapter 2); the hotter an object, the shorter the wavelengths that are emitted (Wien’s Law). Waves of radiation do not need to travel through a medium, such as air or water, in order to transfer heat.

Question 10

Describe conduction heat

Answer 10

Conduction is the molecule-to-molecule transfer of heat energy as it diffuses through a substance. As molecules warm, their vibration increases, causing collisions that produce motion in neighbouring molecules, thus transferring heat from warmer to cooler material. An example is energy conducted through the handle of a pan on a kitchen stove. Different materials (gases, liquids, and solids) conduct sensible heat directionally from areas of higher temperature to those of lower temperature. This heat flow transfers energy through matter at varying rates, depending on the conductivity of the material—Earth’s land surface is a better conductor than air; moist air is a slightly better conductor than dry air.

Question 11

Describe convection

Answer 11

Gases and liquids also transfer energy by convection, the transfer of heat by mixing or circulation. An example is a convection oven, in which a fan circulates heated air to uniformly cook food, or the movement of boiling water on a stove. In the atmosphere or in bodies of water, warmer (less dense) masses tend to rise and cooler (denser) masses tend to sink, establishing patterns of convection. This physical mixing usually involves a strong vertical motion. When horizontal motion dominates, the term advection applies.

Question 12

What is Advection

Answer 12

Horizontal movement of air or water from one place to another.

Question 13

How do Radiation and Conduction pertain to energy budgets?

Answer 13

Radiation and conduction pertain to surface energy budgets, temperature differences between land and water bodies and between darker and lighter surfaces, and temperature variation in Earth materials such as soils

Question 14

What is convections role in energy budgets?

Answer 14

convection is important in atmospheric and oceanic circulation, air mass movements and weather systems, internal motions deep within Earth, and movements in Earth’s crust;

Question 15

How dose advection relate to energy budgets?

Answer 15

Advection relates to the horizontal movement of winds from land to sea and sea to land, the formation and movement of fog, and air mass movements from source regions.

Question 16

How are insolation (incoming solar radiation) values different wound the world?

Answer 16

Consistent daylength and high Sun altitude produce fairly consistent insolation values (about 180–220 watts per square metre; W · m−2) throughout the equatorial and tropical latitudes. Insolation decreases toward the poles, from about 25° latitude in both the Northern and the Southern Hemispheres. In general, greater insolation at the surface (about 240–280 W · m−2) occurs in low-latitude deserts worldwide because of frequently cloudless skies.

Question 17

What is Scattering?

Answer 17

Deflection and redirection of insolation by atmospheric gases, dust, ice, and water vapour; the shorter the wavelength, the greater the scattering; thus, skies in the lower atmosphere are blue

Question 18

What is Diffuse radiation

Answer 18

The downward component of scattered incoming insolation from clouds and the atmosphere. Incoming energy that reaches Earth’s surface after scattering occurs is diffuse radiation. This weaker, dispersed radiation is composed of waves traveling in different directions, and thus casts shadowless light on the ground.

Question 19

What is direct radiation

Answer 19

Direct radiation travels in a straight line to Earth’s surface without being scattered or otherwise affected by materials in the

Question 20

Why is the sky blue and sunsets often red?

Answer 20

A principle known as Rayleigh scattering (named for English physicist Lord Rayleigh, 1881). This principle applies to radiation scattered by small gas molecules and relates the amount of scattering in the atmosphere to wavelengths of light—shorter wavelengths are scattered more, longer wavelengths are scattered less.

We see that blues and violets are the shorter wavelengths of visible light. According to the Rayleigh scattering principle, these wavelengths are scattered more than longer wavelengths such as orange or red. When we look at the sky with the sun overhead, we see the wavelengths that are scattered the most throughout the atmosphere. Although both blues and violets are scattered, our human eye perceives this colour mix as blue, resulting in the common observation of a blue sky.

Question 21

What is refraction?

Answer 21

The bending effect on electromagnetic waves that occurs when insolation enters the atmosphere or another medium; the same process disperses the component colours of the light passing through a crystal or prism.

Question 22

How are rainbows made?

Answer 22

In the same way, a crystal or prism refracts light passing through it, bending different wavelengths to different angles, separating the light into its component colours to display the spectrum. A rainbow is created when visible light passes through myriad raindrops and is refracted and reflected toward the observer at a precise angle

Question 23

What is a mirage?

Answer 23

A type of refraction. Mirage, an image that appears near the horizon when light waves are refracted by layers of air at different temperatures (and consequently of different densities). The atmospheric distortion of the setting Sun in Figure 4.5 is also a product of refraction. When the Sun is low in the sky, light must penetrate more air than when the Sun is high; thus light is refracted through air layers of different densities on its way to the observer

Question 24

Describe reflection

Answer 24

The portion of arriving insolation that is returned directly to space without being absorbed and converted into heat and without performing any work. (See Albedo.)

Question 25

Describe Albedo

Answer 25

The reflective quality of a surface, expressed as the percentage of reflected insolation to incoming insolation; a function of surface colour, angle of incidence, and surface texture.

Question 26

Discrive absorbtion

Answer 26

“Assimilation and conversion of radiation from one form to another in a medium. In the process, the temperature of the absorbing surface is raised, thereby affecting the rate and wavelength of radiation from that surface”

insolation, both direct and diffuse, that is not part of the 31% reflected from Earth’s surface and atmosphere is absorbed, either in the atmosphere or by Earth’s surface. Absorption is the assimilation of radiation by mole-cules of matter, converting the radiation from one form of energy to another. Solar energy is absorbed by land and water surfaces (about 45% of incoming insolation), as well as by atmospheric gases, dust, clouds, and stratospheric ozone (together about 24% of incoming insolation). It is converted into either longwave radiation or chemical energy (the latter by plants, in photosynthesis). The process of absorption raises the temperature of the absorbing surface.

Question 27

How can clouds and aerosols affect the tropospheric energy budget?

Answer 27

Clouds and aerosols are unpredictable factors in the tropospheric energy budget. The presence or absence of clouds may make a 75% difference in the amount of energy that reaches the surface. Clouds reflect shortwave insolation, so that less insolation reaches Earth’s surface, and they absorb longwave radiation leaving Earth (Figure 4.7). Longwave radiation trapped by an insulating cloud layer can create a warming of Earth’s atmosphere called the greenhouse effect

Question 28

What is Global dimming?

Answer 28

“The decline in sunlight reaching Earth’s surface due to pollution, aerosols, and clouds.”

Global dimming is the general term describing the pollution-related decline in insolation to Earth’s surface. This process is difficult to incorporate into climate models, although evidence shows that it is causing an underestimation of the actual amount of warming happening in Earth’s lower atmosphere. One recent study estimates that aerosols reduced surface insolation by 20% during the first decade of this century.