Mar 27, 2015
Size of Earth’s Atmosphere
Air
•invisible, odorless, colorless and tasteless
• extends out 10,000 km (6000 miles)
•98% is within 26km (16 miles) of sea level
• held by gravitational force
• makes life possible (oxygen for animals, carbon dioxide for plants)
• maintains water supply
• insulates us against extreme temperatures
•shields us from ultraviolet radiation
Atmospheric Gases
Composition of the Atmosphere
Composition of the AtmosphereGases
Nitrogen 78 %
Oxygen 21 %
Argon 0.9 %
Neon HeliumKryptonHydrogen } Total < 0.09 %
Important variable amount gases
Water vapor (H2O)Carbon dioxide (CO2)Carbon monoxide (CO)Methane (CH4)Ozone (O3)Sulfur dioxide (SO2)Nitrogen dioxide (NO2)
Composition of the Atmosphere
Atmospheric Particulates
More particulates: smoke from wild fires, meteorite debris, pollen grains, oceanic salt spray, volcanic ash, industrial emissions, dust storms, etc.
Composition of the Atmosphere
Natural
Human-induced
Atmospheric Pressure
Vertical Structure of the Atmosphere
Thermal Layers of the Atmosphere
Meanings
Exosphere = outer
Thermosphere = heat
Mesosphere = middle
Stratosphere = layers
Troposphere = mixing
Each warm zone has a specific source of heat:
Thermosphere - atoms and molecules absorbing UV and being split
Stratosphere - ozone layer absorbs UV
Visible light - absorbed by surface and lowest layer of troposphere
TroposphereTroposphere:•Layer where weather occurs
•Extends 8-18 km (5-11 mi) outwards from the surface
•Deeper in summer and at tropics
Stratosphere - where the Ozone Layer is found
Atmospheric Composition
•Heterosphere: beyond 80 km (50 mi) the gases are layered according to molecular masses
•heterogenous composition
•Homosphere: throughout lowest 80 km (50 mi) the gases are distributed uniformly
•homogenous composition
Division of the Atmosphere
Based on chemical
composition
Based on temperature
(thermal layers)
Based on function
Homosphere (0-50 miles)
Heterosphere (beyond 50 miles)
Troposphere: to 11 miles Stratosphere: 11-30 miles
Mesophere:30-50 miles
Thermosphere: 50 miles out, turning into exosphere
Ozonosphere (9-30 miles)
Ionosphere (40-250 miles)
Ozone absorbs UV radiation, protecting us from the sun
Deep layer of electrically charged molecules and atoms (ions) important in long-distance communications (radio waves) and for aurora displays
Natural Ozone Formation
Human-Induced Atmospheric Change
Ozone Destruction by CFCs
Ozone hole over Antarctica
Human-Induced Atmospheric Change
Consequences:1. the “hole” in the ozone layer (UV-B, UV-C)
2. acid rain and smog (airborne pollution)
3. Ventura County’s worst offenders = particulate matter and ozone pollution
Associated health problems:
respiratory diseases
skin cancers
Depletion of Ozone Layer video
Human-Induced Atmospheric Change
Ozone Loss over the PolesCFCs originate in Northern Hemisphere
redirected by winds (toward poles)
stratospherehigh, thin cloud cover
cold temperatures
Chlorine atoms freed at high rates (poles)
“hole” over Antarctica larger than Arctic
Mid-lats also experiencing ozone thinning
UV passes to Earth’s surface
Definitions
Weather: short-term atmospheric conditions that exist in a specific location during a specific time
Climate: long-term atmospheric conditions that exist in a location, localized or broad, during a prolonged period of time
Weather/climate and the troposphere
Weather and Climate
Elements of Weather and Climate
Weather and Climate
Controls of Weather and Climate
Weather and Climate
Latitude
General Circulation of the Atmosphere
General Circulation of the Oceans
Elevation/Altitude
Topographic Barriers
Storms
Coriolis Effect
Coriolis effect: the apparent horizontal deflection of free-moving objects in response to the rotation of the Earth •Northern Hemisphere: to the right
•Southern Hemisphere: to the left
•deflection is strongest at the poles
•deflection is zero at the equator
•the faster the object, the more deflection
•direction of movement affected, not speed
Coriolis Effect video
Coriolis Effect
Homework1. Have syllabus & textbook?
ADD SLIPS – list/sign.
2. Read Chapter 3.
3. HW #1• Define the UV Index.
• Why is it important?
• Summarize, image, or alternative.
Note: All homework due… the
next week (or) before the midterm.Sub-tropical storm over Ventura County