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ATOC 181 Study Guide - Midterm Guide: Oxygen, Turbopause, Stratopause


Department
Atmospheric & Oceanic Sciences
Course Code
ATOC 181
Professor
Gerard Szejwach
Study Guide
Midterm

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Atmospheric sciences Study of atmosphere, processes, interaction with other system
(Physics, dynamics, demistry, climatology)
Meteorology State of the atmosphere at a given time and location and day-to-
day change measures (T, air P, RH, wind, cloudiness, rainfall and
sunshine)
Rapid, sometimes unpredictable change
Science that deals with the atmosphere and its phenomena and
especially with weather (forecasting)
Climatology Combination of all these elements at a particular place, over a
longer time period (30 years).
Slow variation
Consideration of extremes/seasons
Science that deals with climates and their phenomena
Physical meteorology,
atmospheric physics
Meteorology concerned with atmospheric structure and
composition, transfer of electromagnetic radiation and acoustic
waves, physical processes (formation of clouds and
precipitation), atmospheric electricity.
Synoptic meteorology Description, analysis, and forecasting of large scale atmospheric
motions
Dynamic meteorology Atmospheric motions and their time evolution
Uses analytical approaches (fluid dynamics)
Atmospheric chemistry Study of the chemistry of the atmosphere, composition of
atmosphere (acid rain, ozone depletion, photochemical smog,
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greenhouse gases, global warming)
Physical climatology
(~ meteorology)
Concerned with underlying causes of climate and change
Climatography Formulation and presentation of climatic statistics on the global,
regional, local and micro-scales
Applied climatology Application of climatic statistics to the solution of practical
problems
Main measured parameters Pressure, temperature, min-mas temperatures, humidity, wind
direction and speed, visibility, rain/snowfall amount
Upper air observation
instrument
Radiosonde
Kinds of observations Upper air, marine, aircraft, satellite
First meteorological satellite TIROS-I (slow scan television cameras)
Capability and practicality of observing Earth’s cloud cover
from space (altitude: 600 km – incline 48° to equator)
Earth’s temperature 15°C (-85° to 50°)
Thin layer of atmosphere 100 km (not fixed limit)
“Useful” atmosphere 99% below 30km
50% below 5km
Surface density 1.2 kg/m3
Composition of atmosphere
(near the ground)
Permanent gases:
Nitrogen (78%), oxygen (21%), argon (0.93%)
Variable gases:
Water vapour, CO2, CH4
Water vapour Decreases from the equator towards the poles
Decreases with height (practically no water vapour above 10km
in height)
Major greenhouse gas
Important  change of phases, clouds, precipitations, oceans,
vegetation/life
Water cycle
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Carbon dioxide cycle Large increase since industrial revolution – human activities
Oceans = reservoir of CO2 (~ half is absorbed by ocean)
Ozone (O3) Near surface: less than 1 ppm pollution (smog), health hazard
In stratosphere: 5-12 ppm (97% between 10-30 km)  protection
(UV)
Variability: ozone hole
How trace gases destroy
ozone
Chlorofluorocarbons (CFCs)
UV strikes CFC  chloride break away  chloride collides with
ozone molecule  steals an oxygen atom free oxygen collides
with chlorine monoxide  O2 is released from chlorine dioxide
Methane Greenhouse gas effect
Atmospheric aerosols Liquid or solid particles in suspension
Can reduce the amount of solar energy reaching the surface
Important in formation of clouds/precipitation
Sources of atmospheric
aerosols
Oceans (sea salt), wind erosion (dust), fires, volcanoes, human
activities
Sand storms
Density Mass (kg) per units of volume (m3)
Air density near surface = 1.2 kg/m3
Decrease with elevation
Pressure Force (N) exerted over a unit area (m2)
Unit: Pa (pascal)
Surface pressure = 1000 hPa
Decrease with elevation (first 4 km: -100hPa/km) – expon.
At a given height, depends on mass of atmosphere above
Mass of atmosphere Half of the mass of the atmosphere is below 5.5 km
99% of mass of atmosphere is below 30 km
Composition of atmosphere Higher  no heavy compounds
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