Exam #2 Weather and Climate

Variable Gases are also known as

Greenhouse gases

Atmospheric Origins

Earth formed from particles in solar wind coming together. It was hot and steamy, there was a lot of out gasing(hot gasing being belt out). Precipitation would eventually steam away, now it falls. Contained very little oxygen at first. The oxygen comes from the process of photosynthesis, bacteria formed in oceans, plants.

Thermal structure of the atmosphere

Red line represents temperature. Boundary layers are pause layers which are named for the layer below it and transition from it to above.

Troposphere/tropopause

Troposphere is the weather producing part of the planet. Tropopause is the boundary for the troposphere which is too strong for weather to get through.

Stratosphere

Ozone layer, below ozone the temperature tends to go steady/not change much, ozone and above temperature increases due to UV radiation

Locations of parts of the stratosphere

8-15 miles bottom stratosphere, 30 miles top stratosphere, max ozone lower middle of stratosphere temperature increases to middle to upper part of stratosphere

What follows the stratosphere

Mesosphere, thermosphere

Other atmospheric layers

Layers by composition, chemical composition, layers by electrical properties

Heterosphere

our atmosphere to 55-60 miles up

Homosphere

We live here, chemicals layer up based on atomic weight

Electrical properties-ionosphere

Electrified region of the atmosphere, 45-50 miles & up. D & E highly absorent to AM radio waves, F layer extremely reflective with radio waves

The Earth and the Sun

Earth only receives 2 billionths of the sun’s energy, represents 99.4% of the energy that heats the earth’s surface

Rotation

day & night

Revolution of Earth

Seasons, closest to sun during winter and farthest during summer

Altitude of the sun(angle of the sun above horizon)

At horizon-MOST INDIRECT RAYS, 90 degrees overhead-MOST DIRECT RAYS. Sun is never directly overhead, always in the southern sky

Tropic of Cancer

23.5°N Latitude

Tropic of Capricorn

23.5°S Latitude

“Atmospheres”(unit of measure)

Rays are traversing 1 atmosphere(90 degrees overhead which wouldn’t happen and would be more than 1). Sun 30 degrees above horizon for 2 atmospheres. Watching the sunset is traversing 11 atmospheres

Summer solstice

Most overhead June 21st, overhead tropic of cancer, hottest day mid august

Winter solstice

Overhead tropic of capricorn, December 21st

Earth’s seasons

Sun placement does not equal temperature change→lagger mark(Earth temp has to catch up to sun placement

Circle of illumination

Bondary separating light places & dark places, sunrise/sunset

Heat Budget

• 5% of the sun absorbed by earth's surface

• 20% scattered & reflected by clouds 

• 51% absorbed by earth

• 19% absorbed by atmosphere & clouds

• 51% absorbed by earth 

• 6% scattered from atmosphere

• 4% reflected by surface

Land surfaces react differently and clouds react differently. Budget-what goes in has to equal what comes out

Conduction

Transfer of energy through direct contact(hotter to colder object). There are good conductors and bad conductors

Convection

Vertical transfer of heat energy in our atmosphere

Advection

Horizontal transfer of air properties in our atmosphere, FRONTS

Radiation

Sun to earth, hot to cold,

Short wave-solar radiation

Colder the lower beneath the surface

Terrestrial radiation-long wave radiation

Scattering

Nonreflective

Rayleigh scattering-gas molecules in outer part of Earth’s atmosphere

Mie scattering-haze, pollution

Albedo

How much energy gets reflected away from a given surface

Depends on sun ray angles

Mid-High Albedos

• Old dirty snow: 50-60%

• Thick/rain clouds: 70-80%

• Freshly fallen snow average planetary albedo—> 80-85% 

Low albedos

• Water and sun directly overhead: 3-5%

• Heavily forested areas: 5-10%

• Wet dirt: 10%

• Green grass: 20-25%

• Sand surfaces: 20-30%

• Earth’s average planetary albedo: 30%

• Thin clouds: 25-50%

Earth’s average planetary albedo

30%

Albedo notes

Increase the number more reflective back out, decrease more absorbed

If you have water albedo is low

Poles-reflected away

Atmospheric “Greenhouse” Effect

• greenhouse—> trap heat

• Relatively easy transition of short wave radiation from the atmosphere coupled with the selective absorption of long wave radiation

Absorption and Emission

• Absorbs more than emits — warm

• Emits more than absorbs — cold

Black body object

• perfect absorber and/or perfect emitter

• Since sun and earth both absorb/emit with almost 100% efficiency—> black body objects

Radiative equilibrium temperature of earth

0°F, -18°C

Energy

Property of a system that enables it to do work

Temperature

hotness or coldness of an object or substance, dependent upon molecular motion

Heat

form of energy transferred between objects by the virtue of the temperature difference

Heat capacity

ratio of heat absorbed or released by a system compared to the corresponding temperature rise and fall

water has greater heat capacity than land

Latent heat

Heat energy that is required for the change of state

latent heat is absorbed and released

Very important source of atmospheric energy

latent heat that is released

Deposition, freezing, condensation

latent heat that is absorbed

sublimation, melting, evaporation

Energy surplus

at latitudes between 36°N and 36°S receive more short wave than we give

Energy deficit

above 36°N and below 36°S, gives more than we receive

Latitudinal heat balance facts

• US most likely to see tornadoes climatology wise—zone of conflict

• 30° to 50°  N&S conflict

Lagger Mark

Takes a while for atmosphere to respond

Temperature Measurement History

• mercury in glass tube-banned in federal buildings-based upon molecular motion 

• Thermometer

• Digital thermometer

• Thermograph-has tracking pen using bimetallic sensory plot temp.

Thermometer shelter/exposure

• remember…thermometers are much better energy absorbers than air is

• Colton religion shelter(CRS)

• Thermometer radiation shield(TRS)

Rules for measuring temperature

• no direct sunlight on thermometer temp sensory at any time 

• Well ventilated

• Thermometer should be shielded from radiated surfaces

• Measure 5 ft. Off the surface

• Depending on environment measured over an area naturally vegetated from that area

• More inconvenient the better, more siting, away from where you live

Fahrenheit Scale

• only used in US

• Based upon a liquid in glass thermometer

• ZERO POINT: 32°F

• 98.6°F: Human body temp

• 212°F: boiling point at sea level

Celsius Scale

• widely used around the world minus the US 

• Devised using decimal scale & a “zero point”

• Zero point: 0°C

• Human body temp: 37°C

• Boiling and steaming point at sea level 100°C

• Worldwide aviation uses celsius

Kelvin scale

• used in scientific applications 

• Zero point-stopping of any molecular motion-0

  • 0°K

• No negative numbers

• 273°K: freezing point and melting 

• 373°K: boiling point 

• degree size is the same

Fahrenheit to Celsius

(°F-32) / 1.8 = °C

Celsius to Fahrenheit

°C x 1.8 + 32 = °F

Air temp control

• The primary and other four controls

  • primary- the sun

  • Differential heating of land and water

  • Ocean currents

    • West coast-cold currents

  • Elevation

  • Latitude and geographic

Air temp data/uses

Temp data is gathered at 1000s of stations worldwide on an hourly basis

Heating/cooling degree days

• A unit (“HDD/CDD day”) of measure

• Developed in the early 20th century → heating and cooling engineers

CDD season

January 1 through December 31 

HDD season

July 1 through June 30

Math for CDD and HDD

• Based upon assumption if average temperature outside 65°F would require no energy to heat the building 

• Higher - cooling, lower - heating

  • Math: avg high and low, subtract or add 65

Biometeorological application 

• Heat stress index - increase relative humidity, increase atmosphere saturation 

• Wind chill index-polar regions

• WGBT-wet bulb globe temp

Intro to Atmospheric Pressure

1. Urbanization

2. Limestone layers

Humidity

• Absolute humidity 

• Specific humidity

• mixing ratio