soar 2005 earth’s atmosphere and wind. origin of planets coalescence of matter in circumsolar...
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SOAR 2005SOAR 2005
Earth’s Atmosphere and WindEarth’s Atmosphere and Wind
Origin of PlanetsOrigin of Planets Coalescence of matter in circumsolar
cloud Many Craters Collisions heat! Molten interior Interior layered Denser materials sink to center
Core mostly Iron (Fe) & Nickle (Ni) Crust mostly rocky (CaCO3, SiO2, etc)
Coalescence of matter in circumsolar cloud
Many Craters Collisions heat! Molten interior Interior layered Denser materials sink to center
Core mostly Iron (Fe) & Nickle (Ni) Crust mostly rocky (CaCO3, SiO2, etc)
Planetary AtmospheresPlanetary Atmospheres Form from
Gases from planet’s interior (volcanoes) Gases from impacts (planets)
Terrestrial Planets Mercury – none Venus CO2 with H2SO4 clouds
Mars – CO2 with H2O clouds
Earth – N2 with O2
Jupiter & Saturn – H with NH3 clouds Galilean moons – traces Titan – N2 with CH4
Uranus & Neptune – H with CH4 clouds
Form from Gases from planet’s interior (volcanoes) Gases from impacts (planets)
Terrestrial Planets Mercury – none Venus CO2 with H2SO4 clouds
Mars – CO2 with H2O clouds
Earth – N2 with O2
Jupiter & Saturn – H with NH3 clouds Galilean moons – traces Titan – N2 with CH4
Uranus & Neptune – H with CH4 clouds
Planetary AtmospheresPlanetary Atmospheres
Escape Velocity
Molecular Speed & Temp
or
Escape Velocity
Molecular Speed & Temp
or
center from
planetescape R
2GMv
NAME Mass RadiusWeight
of 150 lb person
Escape Speed
(kg) (km) lb m/s1000 mph
SOL 2E+30 695990 4196 617439 1,381
MERCURY 3E+23 2440 57 4248 9.5
VENUS 5E+24 6052 136 10358 23
EARTH 6E+24 6378 150 11174 25
Luna 7E+22 1737 25 2376 5.3
MARS 6E+23 3397 57 5017 11
JUPITER 2E+27 71492 380 59524 133
Io 9E+22 1820 28 2557 5.7
Europa 5E+22 1570 20 2034 4.6
Ganymede 1E+23 2630 22 2749 6.1
Callisto 1E+23 2400 19 2450 5.5
SATURN 6E+26 60268 160 35473 79
Titan 1E+23 2670 19 2597 5.8
m
kTv
3
Constant sBoltzmann' 231038.1 KJk
kTmv2
3
2
1 2 avg
avg
Planetary AtmospheresPlanetary Atmospheres Presence & size due to combination of
Temperature = Distance from Sol Size of world = escape velocity
Large worlds Keep atmospheres even close to Sol
Small worlds Only have atmospheres far from Sol
Composition due to Size of world
Large worlds keep small molecules (H) Small worlds keep large molecules (N2, O2,
CO2)
Presence & size due to combination of Temperature = Distance from Sol Size of world = escape velocity
Large worlds Keep atmospheres even close to Sol
Small worlds Only have atmospheres far from Sol
Composition due to Size of world
Large worlds keep small molecules (H) Small worlds keep large molecules (N2, O2,
CO2)
kR3
2 molecule
world
worldEscape
mGMT
Inner PlanetsInner Planets Mercury
Small, hot no atmosphere stays Venus
Large, hot thick atmosphere NO WATER H2O H2 + O that binds with C, S, etc
CO2 + H2S04 Clouds Run-away greenhouse effect
Mars Small, cool thin atmosphere & thinning
Evidence of ancient oceans but water now present only as solid and gas
CO2 + H2O Clouds, fogs
Mercury Small, hot no atmosphere stays
Venus Large, hot thick atmosphere
NO WATER H2O H2 + O that binds with C, S, etc
CO2 + H2S04 Clouds Run-away greenhouse effect
Mars Small, cool thin atmosphere & thinning
Evidence of ancient oceans but water now present only as solid and gas
CO2 + H2O Clouds, fogs
Mars & VenusMars & Venus Both primarily CO2 but very different! Both primarily CO2 but very different!
Mars 95.3% CO2Mars 95.3% CO2
Venus 96.5% CO2Venus 96.5% CO2
250K – 273K = -23ºC = -10ºF
250K – 273K = -23ºC = -10ºF
750K – 273K = 477ºC = 890ºF
750K – 273K = 477ºC = 890ºF
Venus: Greenhouse gone wild!Venus: Greenhouse gone wild!
Interaction with SunlightInteraction with Sunlight Sky is blue because blue scatters, red
doesn’t Sky is blue because blue scatters, red
doesn’t
EarthEarth Complex atmospheric evolution
Primordial Atmosphere Lost to space H & He very light molecules, escape easily
Initially like Venus & Mars: mostly CO2
THEN Water condensed into oceans Oceans absorbed CO2
Locked it into rocks (CaCO3 = limestone)
Life flourished in oceans Released free oxygen
Sedimentary rocks turned red Ozone layer formed
Complex atmospheric evolution Primordial Atmosphere Lost to space
H & He very light molecules, escape easily
Initially like Venus & Mars: mostly CO2
THEN Water condensed into oceans Oceans absorbed CO2
Locked it into rocks (CaCO3 = limestone)
Life flourished in oceans Released free oxygen
Sedimentary rocks turned red Ozone layer formed
Evolution of Earth’s Atmosphere
Evolution of Earth’s Atmosphere
Oxygen content created,
maintained by life.
Oxygen content created,
maintained by life.
Atmospheric Structure
Atmospheric Structure
Layers (from surface) due to
Density (Pressure) Radiation Environment Temperature
Layers (from surface) due to
Density (Pressure) Radiation Environment Temperature
Atmospheric Structure
Atmospheric Structure
Layers (from surface)
Troposphere – sphere of weather
Stratosphere – sphere of ozone (O3)
Mesosphere Ionosphere – sphere of ions
Layers (from surface)
Troposphere – sphere of weather
Stratosphere – sphere of ozone (O3)
Mesosphere Ionosphere – sphere of ions
Atmospheric StructureAtmospheric Structure Layers By Temperature Layers By Temperature
Troposphere (“mixing” sphere) 0 – 8 km at poles, 0 – 18 km equator
90% of total mass of atmosphere
Temperature decreases with altitude
Troposphere (“mixing” sphere) 0 – 8 km at poles, 0 – 18 km equator
90% of total mass of atmosphere
Temperature decreases with altitude
Atmospheric StructureAtmospheric Structure Layers By Temperature Layers By Temperature
Stratosphere (tropopause – 50 km) Stratosphere (tropopause – 50 km) Temperature
increases with altitude to Ozone layer
Temperature increases with altitude to Ozone layer
Mesosphere (50-80 km) Coldest part of
atmosphere (<T> = -90°C)
Mesosphere (50-80 km) Coldest part of
atmosphere (<T> = -90°C)
Atmospheric StructureAtmospheric Structure Layers By Temperature Layers By Temperature
Thermosphere (80km outward)“heat” sphere due to particle energies
From insolation (UV – X-ray!)
Thermosphere (80km outward)“heat” sphere due to particle energies
From insolation (UV – X-ray!)
Atmospheric StructureAtmospheric Structure Layers By Function
Ionosphere Thermosphere & Mesosphere Ionized particles (UV + atoms ions + e- +
energy Absorbs -rays, x-rays, UV, cosmic rays Reflects AM radio waves
Layers By Function Ionosphere
Thermosphere & Mesosphere Ionized particles (UV + atoms ions + e- +
energy Absorbs -rays, x-rays, UV, cosmic rays Reflects AM radio waves
Atmospheric Structure
Atmospheric Structure
Layers By Function Ozonosphere (O3 layer)
Upper portion of Stratosphere
Absorbs UV (0.1-0.3 nm), radiates IR
Warmest layer in atmosphere
Harmed by CFC’s Cl + 2O3 Cl + 3O2
… and Cl is free to kill again!
Layers By Function Ozonosphere (O3 layer)
Upper portion of Stratosphere
Absorbs UV (0.1-0.3 nm), radiates IR
Warmest layer in atmosphere
Harmed by CFC’s Cl + 2O3 Cl + 3O2
… and Cl is free to kill again!
Ozone constantly created & destroyed by UV, CFC’s
increase destruction
Ozone constantly created & destroyed by UV, CFC’s
increase destruction
Hole in the ozone layer over AntarcticaHole in the ozone layer over Antarctica
Importance of WindImportance of Wind Arises due to differences in pressure
Distributes heat moisture dust pollutants microscopic life
Arises due to differences in pressure
Distributes heat moisture dust pollutants microscopic life
PaPaPascalPascalmetermeter
NewtonsNewtons
AreaAreaForceForce
PP 22
Air PressureAir Pressure Pressure is force/area = weight of air
column 1 in2 column
weight = 14.7 lb
1 m2 column weight = 10 tonnes
1 tonne = 1000 kg = 2204 lb
Why doesn’t the air pressure crush you when you lie down?
Pressure is force/area = weight of air
column 1 in2 column
weight = 14.7 lb
1 m2 column weight = 10 tonnes
1 tonne = 1000 kg = 2204 lb
Why doesn’t the air pressure crush you when you lie down?
Air PressureAir Pressure Standard Atmosphere
760 mm Hg 29.92 in Hg 33.9 ft. H2O 1013 millibars (mb)
1013 hPa hectopascals
Standard Atmosphere 760 mm Hg 29.92 in Hg 33.9 ft. H2O 1013 millibars (mb)
1013 hPa hectopascals
Weight of column of Hg
Weight of Hg = Weight of Air
Weight of column of air
Hg(tube area)(column height)
= (air presure)(bowl area)
Air PressureAir Pressure Varies with
altitude (in Pa, H in m)
air motion rising air = low pressure subsiding air = high
pressure moving air is at lower
pressure than still (or slower moving air … wind pulls curtains against window screen & airplane wings up!
Varies with altitude (in Pa, H in m)
air motion rising air = low pressure subsiding air = high
pressure moving air is at lower
pressure than still (or slower moving air … wind pulls curtains against window screen & airplane wings up!
155001550055loglog1010
HHPP
WindWind Horizontal motion of air across Earth’s
surface (advection) Updrafts – upward motion of air Downdrafts – downward motion of air Measured by anemometers
1 knot = 1 nautical mile/hour = (1 minute of latitude)/hour = 1.852 kph = 1.15 mph
Speed and Direction recorded
Horizontal motion of air across Earth’s surface (advection)
Updrafts – upward motion of air Downdrafts – downward motion of air Measured by anemometers
1 knot = 1 nautical mile/hour = (1 minute of latitude)/hour = 1.852 kph = 1.15 mph
Speed and Direction recorded
Driving ForcesDriving Forces Gravitational Force
Earth’s gravity holds atmosphere
Pressure Gradient force isobar = line of constant pressure Pressure Gradient force acts perpendicular
Gravitational Force Earth’s gravity holds atmosphere
Pressure Gradient force isobar = line of constant pressure Pressure Gradient force acts perpendicular
kR3
2 molecule
world
worldEscape
mGMT
Driving ForcesDriving Forces Pressure
Gradient force Pressure
Gradient force
Indicated by density of
isobars
Indicated by density of
isobars
Driving ForcesDriving Forces Pressure
Gradient force Pressure
Gradient force
Indicated by density of
isobars
Indicated by density of
isobarsNorth America & Greenland, February 6, 18Z (1 pm EST)
18 hPa across ~400
km
Driving forcesDriving forces Pressure Gradient force
from high pressure to low pressure
Pressure Gradient force from high pressure to low pressure
Driving ForcesDriving Forces Coriolis Force
Acts ONLY ON MOVING objects proportional to velocity ( ) perpendicular to velocity acts over large distances
Does not determine direction water spins down a drain!
Coriolis Force Acts ONLY ON MOVING objects
proportional to velocity ( ) perpendicular to velocity acts over large distances
Does not determine direction water spins down a drain!
The rolling ball follows a straight path seen from above, a curved path seen from the rotating reference frame (riding on the merry-go-round).
The rolling ball follows a straight path seen from above, a curved path seen from the rotating reference frame (riding on the merry-go-round).
velocityvelocity
forceforcevvFF
Coriolis ForceCoriolis ForceDifferent latitudes
“orbit” axis at different
speeds.
Projectile carries small speed, falls
behind high speed equator.
Projectile carries small speed, falls
behind high speed equator.
Coriolis ForceCoriolis Force All moving objects are deflected
to their right in northern hemisphere to their left in southern hemisphere
All moving objects are deflected to their right in northern hemisphere to their left in southern hemisphere
Coriolis force deflects velocity no matter what
the original direction of the
velocity!
Coriolis force deflects velocity no matter what
the original direction of the
velocity!
Coriolis Force:Coriolis Force: All moving objects are deflected
All moving objects are deflected
to their right in
northern hemisphere
to their right in
northern hemisphere
to their left in southern hemisphere
to their left in southern hemisphere
Tropical Cyclone OlyviaTropical Cyclone Olyvia
Hurricane IsabelHurricane Isabel
Coriolis ForceCoriolis Force Northern
Hemisphere Moving objects
deflected to their own right.
Northern Hemisphere Moving objects
deflected to their own right.
Southern Hemisphere Moving objects
deflected to their own left.
Southern Hemisphere Moving objects
deflected to their own left.
L
Storms rotate counterclockwise
Storms rotate counterclockwise
L
Storms rotate clockwise
Storms rotate clockwise
Cyclones & AnticyclonesCyclones & Anticyclones Cyclone – circulation around low pressure
CCW in northern hemisphere CW in southern hemispere
Anticyclone – circ. around high pressure CW in northern hemisphere CCW in southern hemisphere
Cyclone – circulation around low pressure CCW in northern hemisphere CW in southern hemispere
Anticyclone – circ. around high pressure CW in northern hemisphere CCW in southern hemisphere
http://www.usatoday.com/weather/tg/whighlow/whighlow.htm
Driving ForcesDriving Forces Friction
Friction with ground slows wind Extends upward ~ 500 m Varies with surface, time
Friction Friction with ground slows wind Extends upward ~ 500 m Varies with surface, time
Friction with ground slows wind
Surface air slows air aloft
Geostrophic WindsGeostrophic Winds Pressure Gradient Force
creates wind ⊥ to isobars Coriolis Force
deflects motion to right in N. hemisphere
⇒ deflects Coriolis force!
Pressure Gradient Force creates wind ⊥ to isobars
Coriolis Force deflects motion to right in N.
hemisphere ⇒ deflects Coriolis force!
wind velocitywind velocity
Coriolis forceCoriolis force
Pressure Gradient force
Pressure Gradient force
IsobarsIsobarsForces
BalanceForces
Balance
wind along isobarwind along isobar
Wind deflects due to Coriolis force
Wind deflects due to Coriolis force
Coriolis force acts perpendicular to
new wind direction
Coriolis force acts perpendicular to
new wind direction
Geostrophic WindsGeostrophic Winds Pressure Gradient Force
creates wind ⊥ to isobars Coriolis Force
deflects motion to its right in N. hemisphere to its left in S. hemisphere
aligns wind with isobars
Pressure Gradient Force creates wind ⊥ to isobars
Coriolis Force deflects motion
to its right in N. hemisphere to its left in S. hemisphere
aligns wind with isobars
Surface Winds: Not GeostrophicSurface Winds: Not Geostrophic Friction slows winds at surface
Reduces Coriolis force Pressure Gradient force dominates
Friction slows winds at surface Reduces Coriolis force Pressure Gradient force dominates
Importance of WindImportance of Wind Arises due to differences in pressure
Distributes heat moisture dust pollutants microscopic life
Arises due to differences in pressure
Distributes heat moisture dust pollutants microscopic life
PaPaPascalPascalmetermeter
NewtonsNewtons
AreaAreaForceForce
PP 22
Temperature ControlsTemperature Controls
Sunlight heats land, water, air Land warms, heats air Air circulates
Convection cells warms -> expands -> rises cools -> contracts -> sinks
Water circulates Currents driven by wind & Earth rotation Water temperature increases SLOWLY
Large energy change needed for small temp. change
Sunlight heats land, water, air Land warms, heats air Air circulates
Convection cells warms -> expands -> rises cools -> contracts -> sinks
Water circulates Currents driven by wind & Earth rotation Water temperature increases SLOWLY
Large energy change needed for small temp. change
Convection CellsConvection Cells Hot surface heats air Air expands,
becomes less dense than surroundings rises, spreads out at top
Air aloft cools, becomes more dense than surroundings sinks, spreads out on surface
Hot surface heats air Air expands,
becomes less dense than surroundings rises, spreads out at top
Air aloft cools, becomes more dense than surroundings sinks, spreads out on surface
Atmospheric CirculatonAtmospheric Circulaton Rising Air
Cools Water vapor condenses (usually) results in clouds Lowers surface pressure
Rising Air Cools Water vapor condenses (usually) results in clouds Lowers surface pressure
Atmospheric CirculatonAtmospheric Circulaton Falling Air
Warms DRY (lost mosture rising) Increases surface pressure
Falling Air Warms DRY (lost mosture rising) Increases surface pressure
Atmospheric CirculationAtmospheric Circulation Sunlight heats ground Ground heats air , drives convection
from subsolar latitude
Sunlight heats ground Ground heats air , drives convection
from subsolar latitude
Maximum Insolation
Subsolar latitude is 23.5º
N/S on the solstices
Subsolar latitude is 23.5º
N/S on the solstices
Subsolar latitude is 0º on the equinoxes
Subsolar latitude is 0º on the equinoxes
Atmospheric Circulaton Atmospheric Circulaton
Air rises from
subsolar latitude,
clouds form &
precipitate, air aloft
moves N & S, cools,
dries & sinks at about 30º
N & S
Air rises from
subsolar latitude,
clouds form &
precipitate, air aloft
moves N & S, cools,
dries & sinks at about 30º
N & S
Moist air rising humid
Moist air rising humid
Dry air falling Arid
Dry air falling Arid
Air aloft cools until it sinks
Air aloft cools until it sinks
Air spreads N & S on surface
Air spreads N & S on surface
Driven by heating near equator
Driven by heating near equator
Atmospheric CirculatonAtmospheric Circulaton
Air from aloft sinks
near poles,
moves N & S along surface
Air from aloft sinks
near poles,
moves N & S along surface
Moist air rising humid
Moist air rising humid
Dry air falling Arid
Dry air falling Arid
Surface flows converge,
rise
Surface flows converge,
riseAir warms
and moistens along surface
Air warms and moistens along surface
Driven by cooling near
poles
Driven by cooling near
polesCold, dry air falling AridCold, dry air falling Arid
Moist air rising stormy
Moist air rising stormy
Moist air rising stormy
Moist air rising stormy
Dry air falling Arid
Dry air falling Arid
Dry air falling Arid
Dry air falling Arid
Pressure ZonesPressure Zones
Rising Air: Low
Pressure
Rising Air: Low
Pressure
InterTropical Convergence
Zone
InterTropical Convergence
Zone
Pressure ZonesPressure Zones
Falling Air: High
Pressure
Falling Air: High
Pressure
Pressure ZonesPressure Zones
Pressure
Zones: air motion is vertical so there is little wind!
Pressure
Zones: air motion is vertical so there is little wind!
Wind ZonesWind Zones
Winds: Falling air spreads North & South along
surface.
Winds: Falling air spreads North & South along
surface.
But the winds don’t go straight!But the winds don’t go straight!
Wind ZonesWind ZonesWinds named
for direction they are
from
Winds named
for direction they are
from
WesterliesWesterlies
WesterliesWesterlies
NE TradesNE Trades
SE TradesSE Trades
EasterliesEasterlies
EasterliesEasterlies
Doldrums
Horse Latitudes
Horse Latitudes
Polar Front
Polar Front
Windless zones names vary
Windless zones names vary
General Atmospheric Circulation
General Atmospheric Circulation
Cross sectional view Cross sectional view
ITCZITCZSTHPCSTHPCEasterly Trades
Easterly Trades
Polar HighPolar High
WesterliesWesterliesPolar Easterlies
Polar Easterlies
Dold
rum
sD
old
rum
s
Hors
e
Lati
tudes
Hors
e
Lati
tudes
Pola
r Fr
on
tPola
r Fr
on
t
World Pressure Cells: JanuaryWorld Pressure Cells: January
H
North American HighNorth American High
Parallel isobars over (low friction) ocean ⇒ rippin’ winds!!!
Parallel isobars over (low friction) ocean ⇒ rippin’ winds!!!
Aleutian Low
Aleutian Low
Islandic Low
Islandic Low
Siberian High
Siberian High
World Pressure Cells: JanuaryWorld Pressure Cells: January
Parallel isobars over (low friction) ocean ⇒ rippin’ winds!!!
Parallel isobars over (low friction) ocean ⇒ rippin’ winds!!!
Tibetan Low
Tibetan Low
Upper Atmospheric WindsUpper Atmospheric Winds Jet Streams: Fast Winds Aloft
Polar Jet Stream Above Polar Front (midlatitude air meets polar) Rossby waves move loops north & south 7,600 – 10,700 m (25-35 kf) speeds up to 300 kph (190 mph)
Jet Streams: Fast Winds Aloft Polar Jet Stream
Above Polar Front (midlatitude air meets polar) Rossby waves move loops north & south 7,600 – 10,700 m (25-35 kf) speeds up to 300 kph (190 mph)
Upper Atmospheric WindsUpper Atmospheric Winds Jet Streams: Fast Winds Aloft
Subtropical Jet Stream above Subtropical highs (tropical air meets midlatitude)
9,100 – 13,700 m (30-35 thousand feet) speeds less than Polar Jet Stream
Jet Streams: Fast Winds Aloft Subtropical Jet Stream
above Subtropical highs (tropical air meets midlatitude)
9,100 – 13,700 m (30-35 thousand feet) speeds less than Polar Jet Stream
Polar Jet StreamPolar Jet Stream Determines N.Am. winter weather Strong west wind monitored by weather balloons
Determines N.Am. winter weather Strong west wind monitored by weather balloons
Check out PBS’s explanation!:
www.pbs.org/wgbh/nova/vanished/jetstream.html
Polar Jet StreamPolar Jet Stream Determines N.Am. winter weather Rossby waves bring cold air south
Determines N.Am. winter weather Rossby waves bring cold air south