21. Insolation And Temperature

INSOLATION AND TEMPERATURE J.T. II Olivar, MAEd Faculty of Arts and Letters University of Santo Tomas

Outline of the Lecture  Insolation

and Temperature  [Processes of] Heating and Cooling the Atmosphere  Latent Heat  Spatial and Seasonal Variations in Heating and Cooling

Insolation  Infrared

Waves  [White] Light  Ultraviolet Waves

[Processes of] Heating and Cooling the Atmosphere 1. 2. 3. 4. 5. 6. 7. 8.

Conduction Convection Radiation Absorption Reflection Transmission Scattering Adiabatic cooling and warming

Conduction  The

movement of heat energy from one molecule to another without changes in their relative positions. – Moist air is slightly more efficient conductor than dry air.

Convection  Heat

is transferred from one point to another by moving liquid or gas. – In convection, the molecules physically move away from the heat source.

Radiation  The

process by which heat energy is emitted from a body. – A body that emits the maximum amount of radiation possible [at every wavelength] is called a blackbody.

Absorption  Heat

energy striking an object can be absorbed by the object like water into sponge. – Dark-colored surfaces are much more efficient absorbers in the visible portion of the spectrum than are light-colored surfaces.

Reflection  Is

the ability of an object to repel waves without altering either the objects or the waves. – An object that is good absorber is a poor reflector, and vice versa.

Transmission  Is

the process whereby a wave passes completely through a medium. – Transmission depends on the wavelength of the rays.

Scattering  Particulate

matter and gas molecules in the air sometimes deflect and redirect light waves. – Shorter waves are readily scattered than longer ones.

Adiabatic Cooling  Cooling

by expansion in rising air.

– The expansion that occurs in rising air is a cooling process even though no heat is taken away.

Adiabatic Warming  Warming

by compression in descending air. – The molecules draw closer together and collide more frequently thus resulting in a rise in temperature even though no heat is added from external sources.

Latent Heat  Latent

– lying hidden

– Latent – Latent

heat heat

of of

evaporation condensation

Spatial and Seasonal Variations in Heating and Cooling  Latitudinal

differences

– Angle of incidence – Day length – Atmospheric obstruction – Latitudinal radiation balance  Land

and water contrast

– Heating – Cooling

Heating  Water

has a higher specific heat than

land.  Sun rays penetrate water more deeply than they do on land.  Water is highly mobile and land is immobile.  The unlimited availability of moisture on a water surface.

Cooling  Northern

hemisphere

– Land hemisphere – 39% land  Southern

hemisphere

– Water hemisphere – 19% land