Chapter 17 page 474 The Atmosphere: Structure and Temperature

A. Atmosphere Characteristics 1. Introduction a.Earth has a unique atmosphere for life b.Weather 1)Specific time and place 2)Short term and constantly changing c.Climate 1)Long term 2)Based off observations of weather 3)Helps describe a place or region

2. Composition of the Atmosphere a. Major components 1) Nitrogen – 78% 2) Oxygen – 21% 3) Argon – 0.93% 4) Carbon dioxide a) 0.039% b) Helps warm the earth c) Needed for plant growth

3. Variable Components a. Water vapor 1) Source for clouds and precip 2) Absorbs heat from earth 3) Absorbs some solar radiation b. “Dust” 1) Sea salts from breaking waves 2) Fine soil 3) Smoke and soot 4) Pollen and microorganisms 5) Ash

c. Ozone 1) O 3 2) Formation a) O 2 absorbs UV light b) O 2 splits c) Single O and O 2 combine 3) Located in a thin layer 4) Blocks UV-b and UV-c 5) 3mm thick (hole is 1mm thick) 6) CFCs

Ozone and ultraviolet light All of C is absorbs Most of B is absorbed A little of A is absorbed

4. Height & Structure of Atmosphere a. No distinct line b/w space and atmosphere b. Atmosphere thins until there is no more gas detected

c. Atmospheric pressure 1) Weight of the air above you 2) Decreases as with altitude

d. Temperature change 1) Troposphere a) Bottom layer b) Temperature decreases with altitude c) Almost all weather d) Temp drops until tropopause e) 7.5 miles

2) Stratosphere a) Temperature increases with altitude b) Contains ozone c) Ozone heats up from absorbing UV d) Jets fly here

3) Mesosphere a) Temp decreases with altitude b) Approaches about -130˚F c) Meteors burn up 4) Thermosphere a) Upper layer with no defined limit b) Temp increases w/altitude c) O 2 and N 2 are absorbing solar radiation d) Northern lights (ionosphere)

5. Earth-sun Relationships a. Earth’s motions 1) Rotation a) Spinning on axis b) Spins once every 24hrs 2) Revolution a) Movement of earth in orbit b) 70,215 mph

b. Earth’s Orientation 1) Tilted 23.5˚ 2) Causes seasons 3) Pointed at Polaris

c. Seasons 1) Summer Solstice a) First day of summer b) Axis is leaning towards the sun c) June 21 or 22 d) Longest day 2) Winter Solstice a) First day of winter b) Axis leaning away from the sun c) December 21 or 22 d) Shortest day

3) Autumnal equinox a) September 22 or 23 b) Start of Fall c) Day and night are equal length d) Not tilted towards or away from the sun 4) Spring equinox a) March 21 or 22 b) Start of Spring c) Day and night are equal length d) Not tilted towards or away from the sun

B. Heating the Atmosphere 1. Energy transfer as heat a.Heat – energy transfer from one object to another b/c difference of temperatures b.Temperature – average amount of kinetic energy in individual atoms of a substance

c. Conduction 1) Heat transfer through matter by molecular activity 2) Transfers from high temp to low temp 3) Metals good conductors, air is not

d. Convection 1) Transfer of heat by mass movement or circulation within a substance 2) Oceans and air 3) Warm things expand and become less dense 4) Water rises, cooler water sinks

Convection currents in mantle

Sea and Land Breeze

e. Radiation 1) Only one to travel through a vacuum (doesn’t need a medium) 2) Hotter objects radiate more energy

2. What happens to solar radiation a. Energy is absorbed – converts energy to heat b. Transmitted 1) Energy is not transferred or converted 2) Air and water c. Energy bounces off – not absorbed or transmitted

d. Reflection and Scattering 1) Reflection – light bounces off an object 2) Scattering – produces larger number of rays that go in different directions

e. Absorption 1) Crust heats up and sends heat into air 2) Atmosphere traps this b/c it has longer wavelengths than from the sun 3) Greenhouse effect (H 2 O & CO 2 )

C. Temperature Controls 1. Why temperatures vary a.Land and Water 1)Land heats up and cools down faster 2)Land can reach hotter and colder temps compared to water 3)Temperature ranges are greater over land

LAND VS. WATER Both have the same latitude to control variables - Same length of day - Same angle of sun’s rays

b. Geographic Position 1) Windward – wind blows from ocean to shore 2) Leeward – wind blows from land to ocean

Spokane is cut off by Cascade Range ◦ Seattle has marine weather ◦ Spokane has continental weather

c. Altitude Figure 18 pg 491

d. Cloud Cover and Albedo 1) Albedo – how much radiation is reflected by a surface 2) Clouds have a high albedo 3) Cloudy days a) Cooler temperatures b) Block radiation 4) Cloudy nights a) Warmer temperatures b) Trap radiation/heat