Air pollution factors:

Prevailing winds: Winds can disperse pollutants across large areas, or concentrated it depending on topography. High concentrations in urban areas. Pollution made in LA get swept by the prevailing winds from the ocean east. Those winds carry the pollution to a mountain range, causing them to stay in LA.

Topography of landscape: The landscape determines whether pollutants are dispersed or concentrated in an area.

Temperature inversion: Normal conditions have air cool as it rises. In inverse conditions, air warms with elevation – warm layer acts as a lid à dense air below can’t rise – traps pollutants. Occurrence: radiative cooling on clear nights + cold air drainage

Clean air Act Regulated what industries could put in the atmosphere, which stopped power companies from emitting sulfur oxide into the atmosphere, leading to less acid deposition.

Atmospheric Energy:

Troposphere – lowest most layer in the atmosphere

Energy gets intercepted by lots of things: land, ocean, clouds, gases, dust, etc. There is an imbalance in energy receipt and distribution, with most of it being in the low latitudes (equator)

The atmosphere deals with shortwave radiation (from sun) differently from longwave radiation (earth’s surface)

Radiation from sun can: Reflect back to space, get absorbed from surface

Energy absorbed from the surface must be released by the surface eventually

Energy can be: Transmitted, Scattered, or Reflected

Transmitted energy is when the energy reaches the earths surface without hitting anything else. When it reaches the earth’s surface its Direct Radiation

Absorbed energy is the assimilation of radiation from one form of energy to another (ie: CO2 and water vapor absorb solar energy radiation)

Scattering is when light gets bounced around in the atmosphere without altering the wavelengths. When it reaches the earth’s surface its Diffuse Radiation.

The reason the sky is blue is because the gas molecules are very good at scattering the shorter visible wavelengths (purple, blue), so the human eye sees blue.

When the sky is polluted with dust and soot, they’re better at reflecting the longer wavelengths (red, orange), causing a red sky when something like a wildfire happens

Insolation drives the earth’s atmosphere system. Very high incoming solar radiation in deserts.

The reason its higher at deserts than the equator is clouds reflecting energy back to space. Higher cloud albedo in the equator. It rains a lot at equatorial rainforests causing high amount of rain and clouds. Intense heating at the equator causes a lot of evaporation.

Albedo – reflectivity of a surface; expressed as % of insolation reflected.

The color black has a much lower albedo and absorbs a higher percentage of radiation.

Earth’s avg. albedo: 31%. Equator: 19-38%. Polar regions: 80%.

Clouds can: 1) Help keep the early cooler from albedo (cloud albedo), or 2) Trap longwave radiation leaving the earth’s surface, slowing its departure (cloud greenhouse).

69% of incoming radiation is absorbed by the earth’s surface.  45% of that is absorbed by land or water. The other 24% is absorbed by the atmosphere (gases, dust, clouds, ozone).

How to move that 45% away from the surface

Latent Heat Transfer: Evaporation of water (removes 20 units of longwave energy)

Conduction:

Convection:

Radiative transfer: Deals with the energy leaving the surface and moving to the energy, greenhouse effect bounces the greenhouse energy back and forth until is escapes.

Greenhouse Effect: Energy is getting absorbed into the atmosphere but is getting trapped, with the atmosphere delaying transfer of heat from Earth to space.

Stratus clouds are darker and reflect most shortwave radiation. Has a cooling effect because little longwave radiation gets absorbed and reradiated.

Cirrus clouds are lighter and thicker, transmit a lot of shortwave radiation to the surface, and has a warming effect because it slows the release of longwave radiation.

Tropic – Tropic – Energy Surplus, more energy coming in than released

Poles – Energy Deficit, more energy released than coming in

Balanced at around 36 degrees

To equalize the imbalance, global circulation happens

The sun will be highest at solar noon. Incoming solar radiation is at its peak at solar noon.

The highest temperatures happen a few hours after solar moon. Although theres a deceleration in heat reaching the surface, it’s still high enough to cause a temperature increase for a few hours, even though its slowing.

The lowest temperature is the moment before sunrise because theres no radiation from the sun cooling in and the surface has been emitting radiation all night.

Simplified Surface Energy Budget

+SW: Insolation

-SW: Reflection

+LW: Infrared

-LW: Infrared

Latent Heat – Energy involved in changing the state of water (evaporation)

Sensible Heat – Heat that we feel and can sense. Ie: walking on sidewalk barefoot

Temperature – The measure of average kinetic energy of individual molecules in matter

Heat – Form of energy that flows along a gradient (only sensible can be felt)

Temperature controls:

Latitude – Temperatures are reduced as you move north or south of the equator

Altitude – Higher altitude has lower avg. temp than lower altitudes

Cloud Cover – Low thick clouds keep the earth surface warmer

Land-Water Heating Differences (next page)

Places near the equator have lower deviation in temperature because the suns always high in the sky. Places a little further from the equator might have higher highs but they get much lower than equator temps.

Being on the ocean decreases varying temperatures. Edinburgh has a higher latitude than Montreal, but Montreal has the higher deviation though because its not near the ocean.

Edinburgh is a maritime climate, Montreal is a continental climate.

Barrow Alaska: Temperatures go up a lot in summer because the sun doesn’t set. In the winter the sun is very low, meaning its very cold.

Land Water Heating Differences:

Evaporation is higher over water surface.

Transparency affects transmission of solar radiation.

Water has a higher specific heat than soil or rock, meaning it heats or cools slower.

Movement increasing mixing and reduces temp. difference in water.

Continental climates have much larger ranges of temperature from summer to Winter. Ie: Wichita, KS.

Maritime Climates have a much smaller range. San Francisco, CA.

Continental Climates warm and cool very quickly.

Maritime Climates warm and cool slowly.

January temperature map – Thermal Equator moves southward

July temperature map – Thermal Equator moves northward

The thermal equator drops/pulls a lot more over continents (like South America) because the land heats more

Air Temp & Human Body

Avg. body temp is 36.8 Celsius

Humidity, Wind Speed, and Air Temperature affects our comfort

Wind chill – Correlates cold and wind speed. Stronger wind, lower wind chill index, vice versa.

Heat Index – Correlates heat and humidity. Higher humidity, Higher heat index, vice versa.

Urban Heat Islands

Lots of cement, little water, and lots of people causes heat.

Highest temperatures usually located in the city core

Material – replace grass with cement, which absorbs energy very quickly. No water on landscape anymore. No evaporation.

Geometric Shape – No water still

Human Activity – Pollution and CO2

Impermeable Surface – Caused by cement, energy cant go through it

Pollution – Cars, Factories