Radiation, Global energy budget and Temperature

Sun Spots

spots of higher energy release on the sun

Sun Energy

• travels through space as Electromagnetic Radiation

• fuels power sources (solar panels)

• supports nearly all life on earth

Electromagnetic Radiation (EMR)

• travels at speed of light

• emitted in all directions

EMR radiation of objects

• warmer objects emit more

• warmer objects emit shorter wavelengths

Sun and EMR

UV-light, visible, infrared radiation (insolation or shortwave)

Earth and EMR

mainly thermal infrared radiation (longwave)

Transmission

radiation passes through a medium and there is no loss or change in intensity

Absorption

energy of radiation is converted to heat

Scattering

weaker radiation scattered in different directions

Reflection

radiation is reflected without losing intensity

Albedo

measure of surface reflectivity, or % of insolation reflected from a surface

Modes of energy transport

• radiation

• conduction

• convection

Radiation

transmission of energy by waves

Conduction

transfer by molecule contact from higher to lower energy

Convection

transfer by movement of fluid

Sensible heat

air/water of one temperature moves to a location of a different temperature

Latent heat

associated with the movement of water vapor (evapotranspiration, like sweat)

Top of the atmosphere

about 100 km above the earths surface

Why use “budget” in Global Energy Budget

the budget uses units to quantify EMR

Positive values

move towards surface (short waves)

Negative values

move away from surface (long waves)

Solar radiation latitudinal imbalance

there is an energy surplus in the equator, while there is an energy deficit in the poles

3 ways to restore balance

1. warm air transfer: sensible heat transfer

2. warm water transfer: sensible heat transfer

3. water vapor transfer: latent heat transfer

What are Temperature patters determined by?

• Latitude

• Proximity to large bodies of water

• Elevation

• Surface Cover

Temperature and Latitude

the higher in latitude the colder it becomes

Net Radiation

higher latitudes receive less net overall, and it varies more throughout the year

Bodies of water and Temperature

Large bodies of water (Lakes and oceans) are able to hold temperature better than land, therefore they are able to emit heat or cold temps in the opposing time of year

Elevation and Temperature

The higher in elevation the lower temperature because lower atmosphere is heated from earths surface

Ambient atmosphere

an amount of area of land that may, or may not, warm the atmosphere above it

Surface Cover and Temperature

some materials (concrete, etc.) in cities can absorb heat and emit it at night