Chris Henze, NASA Ames, Public
Domain, http://people.nas.nasa.gov/
~chenze/fvGCM/frances_02.mpg
Lecture 10: Wind
Introduction to Oceanography
Winds at
~jet plane
altitude
Introduction to
Oceanography
Pacific surface wind
forecast-hindcast, National
Weather Service
Environmental Modeling
Center/NOAA, Public
Domain, GIF by E. Schauble
using EZGif
1
pH Scale
•  pH scale = Logarithmic scale
pH = − log10 (H + )
•  Neutral (pure) water:
–  1/(5.5x108) water molecules is disassociated
–  there are about 55 moles of water per liter
€
Concentration of H+=
55/(5.5x108) = 10–7 moles/liter
–  Neutral water pH = 7
•  lower pH = acid, higher pH = base
pH Scale
Stephen Lower,
Wikimedia Commons,
CC A S-A 3.0, http://
en.wikipedia.org/wiki/
File:PH_scale.png
2
The Carbonate Buffer System
•  Seawater pH = ~8.0 (slightly basic)
•  Maintained by carbonate buffer system:
−
CO 2 + H 2O ⇔ H 2CO 3 ⇔ H + + HCO 3 ⇔ 2H + + CO 3
Carbonic Acid
€
Bicarbonate
ion
2–
Carbonate
ion
•  Increase CO2 in water, acidity increases
What happens to pH?
•  Add acid and CO2 is produced
The CO2 system and carbonate
•  Deep waters form at the poles: High
CO2 and therefore acidic
•  Acidity interacts to dissolve calcium
carbonate (CaCO3) deposits on the
deep sea floor
–  Acidity and temperature control carbonate
compensation depth (CCD)
3
Questions
Image from UNESCO, Presumed Public Domain, http://ioc3.unesco.org/oanet/FAQacidity.html
Wind
Wind sea, N. Pacific, Winter 1989, M/V
NOBLE STAR/NOAA, Public Domain,
http://commons.wikimedia.org/
wiki/File:Wea00816.jpg
•  Lecture 8: Atmospheric Circulation
4
Atmosphere-Ocean Coupling
•  Why study atmospheric circulation?
–  Atmosphere & ocean processes are
intertwined
–  Atmosphere-ocean interaction moderates
surface temperatures, weather & climate
•  Weather: local atmospheric conditions
•  Climate: regional long-term weather
–  Atmosphere drives most ocean surface
waves and currents (our next topic)
Composition of the Atmosphere
•  Dry Air: 78% Nitrogen, 21% Oxygen
•  BUT it is never completely dry
–  Typically contains about 1% water vapor
Chemical residence time of water vapor in the air is
about 10 days
(liquid water residence time in
ocean: 3x103 years!)
–  Liquid evaporates into the air,
then is removed as dew, rain,
or snow
–  Warm air holds much more
water vapor than cold air
Figure by Greg Benson, Wikimedia Commons
Creative Commons A S-A 3.0,
http://en.wikipedia.org/wiki/File:Dewpoint.jpg
5
Density of Air
•  Typical air density ~ 1 mg/cm3
12000
–  About 1/1000th the
density of water
–  Air is much easier to compress
than water
10000
Everest 8848m
8000
Elevation (m)
•  Temperature and pressure
affect the density of air
•  Temperature: Hot air is less
dense than cold air
•  Pressure: Air expands with
elevation above sea level
Passenger
jet 10-13km
6000
Mt. Whitney 4421m
4000
2000
Empire State Bldg. 450m
0
0
40000
80000
120000
Pressure (N/m2)
Figure by E. Schauble,
using NOAA Standard Atmosphere data.
Density & temperature of Air
•  Rising air expands
& cools
–  Vapor condenses
into clouds,
precipitation
•  Sinking air is
compressed and
warms
–  Clear air
Figure adapted from Nat’l Weather Service/
NOAA, Public Domain,
http://oceanservice.noaa.gov/education/yos/
resource/JetStream/synoptic/clouds.htm
2000 meters
15ºC
15ºC
1000 meters
24ºC
15ºC
34ºC
15ºC
(1.4% H2O)
6
Expanding Air Cools and Condenses
•  Like opening a pressurized bottle of soda
•  Air expands and cools
•  Water vapor condenses -- cloud formation
MMovies by J. Aurnou, E. Schauble, UCLA
Qu
e
sti
on
s
mov1
Figure adapted from Nat’l Weather Service/
NOAA, Public Domain,
http://oceanservice.noaa.gov/education/yos/
resource/JetStream/synoptic/clouds.htm
2000 meters
15ºC
15ºC
1000 meters
24ºC
15ºC
34ºC
15ºC
(1.4% H2O)
7
Solar Heating of the Earth
•  Solar energy absorbed unevenly over Earth’s surface
•  Energy absorbed / unit surface area varies with:
–  Angle of the sun
–  Reflectivity of the surface (i.e., ice v. ocean)
–  Transparency of the atmosphere (i.e., clouds)
23.5º
Przemyslaw "Blueshade" Idzkiewicz,
Creative Commons A S-A 2.0, http://
commons.wikimedia.org/wiki/
File:Earth-lighting-wintersolstice_EN.png
Solar Heating of the Earth
Sunlight heats the ground
more intensely in the
tropics than near poles
• 
file:///Users/schauble/EPSS15_Oceanography/
Images_and_movies/Insolation2.swf Heilemann CCU/
NSF Flash
Sunlight
intensity (top of
atmosphere)
Sunlight
intensity
(ground)
Figure by William M. Connolley using
HadCM3 data, Wikimedia Commons, Creative
Commons A S-A 3.0,
http://commons.wikimedia.org/wiki/
File:Insolation.png
8
Solar Heating & the Seasons
June 20-21: N.
Pole tilted
towards Sun
Not to scale!
Sept. 22-23: Sun
shines on both poles
equally
Oct. 26: We
are here
March 20-21: Sun
shines on both poles
equally
Dec 21-22: N.
Pole tilted away
from Sun
Background image: Tauʻolunga, Creative Commons A S-A 2.5, http://en.wikipedia.org/wiki/File:North_season.jpg
•  Seasons are caused by Earth’s 23.5o tilt
•  Northern summer: north hemisphere points at sun
Solar Heating & the Seasons
NASA animation by Robert Simmon, Public Domain, data ©2011 EUMETSAT
http://earthobservatory.nasa.gov/IOTD/view.php?id=52248&src=ve
9
Redistribution of Solar Heat Energy
• 
• 
• 
• 
• 
Equator absorbs more heat from the sun than it radiates away (net > 0).
Polar regions radiate much more heat than they absorb from the sun(!)
E.g., Equator isn’t that Hot; Poles aren’t that Cold
Evidence that the atmosphere (~2/3) & oceans (~1/3) redistribute heat
Result: convective heat transfer moderates climate
CERES/NASA animation, Public Domain, http://earthobservatory.nasa.gov/GlobalMaps/view.php?
d1=CERES_NETFLUX_M
10
EQUATOR
POLES
Redistribution of Solar Heat Energy
•  Convective heat transfer moderates Earth climate
•  Heated air expands & rises, then cools & sinks
Adapted from image at http://www.yourhome.gov.au/technical/images/62a.jpg, Public Domain?
Atmospheric Circulation Without Rotation
Cold, more dense air
sinks near the Poles
Background image
from Smári P.
McCarthy, Creative
Commons A S-A 3.0,
http://
commons.wikimedia.or
g/
wiki/File:Earth_equator
_northern
_hemisphere.png
Warm, less
dense air rises
near the
Equator
Cold, more dense air
sinks near the Poles
11
Questions
Not quite right!
ACTUAL Atmospheric Circulation
Figure from NASA, Public Domain, http://sealevel.jpl.nasa.gov/overview/climate-climatic.html
12
Lab Coriolis Movies
Stationary Observer
•  Movies made by
Rob Hyde, UCLA
Lab Coriolis Movies
13
CCW Rotation, 25 rpm
Lab Coriolis Movies
CW Rotation, 41 rpm
Lab Coriolis Movies
14
Coriolis Effect Movies
Movie: University of Illinois (not sure if that’s the original source) http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/fw/crls.rxml
The Coriolis Effect on Earth
•  Surface velocity
increases from pole to
equator
•  Points on the equator
must move faster than
points near the poles to
go around once a day
•  Latitude velocity
differences lead to
curving paths
–  Example: Merry-go
round
National Snow and Ice Data Center, free for educational
use, http://nsidc.org/arcticmet/factors/winds.html
15
The Coriolis Effect
•  To an Earthbound observer (i.e., us):
•  Northern Hemisphere: Earth’s
rotation causes moving things to
curve to their right
Moving things: Air masses, oceanic flows,
missiles, anything with mass
•  Southern Hemisphere:
Earth’s rotation causes moving
things to curve to their left
National Snow and Ice Data Center, free
for educational use, http://nsidc.org/
arcticmet/factors/winds.html
The Coriolis Effect
•  Strength of Deflection varies with latitude:
–  Maximum at the poles
–  Zero(!) at equator
–  Faster a planet rotates, the stronger the
Coriolis effects
–  The larger the planet, the stronger the
Coriolis effects
16
But wait – why do storms
(including hurricanes and cyclones) go
backwards?
Northern Hemisphere: Hurricane Isabel (2003) NASA,
Public Domain, http://visibleearth.nasa.gov/view_rec.php?
id=5862
Southern Hemisphere: Cyclone Drena (1997)
NASA, Public Domain,
http://www.ngdc.noaa.gov/dmsp/hurricanes/
1997/drena.vis.gif (now moved)
Questions ?
Atmospheric Circulation including Coriolis
Figure from NASA, Public Domain, http://sealevel.jpl.nasa.gov/overview/climate-climatic.html
17
Actual
forecast of
surface winds
Pacific surface wind
forecast-hindcast, National
Weather Service
Environmental Modeling
Center/NOAA, Public
Domain, GIF by E. Schauble
using EZGif
Atmospheric Circulation including Coriolis
•  3 convection cells in each hemisphere
–  Each cell: ~ 30o latitudinal width
•  Vertical Motions
–  Rising Air: 0o and 60o Latitude
–  Sinking Air: 30o and 90o Latitude
•  Horizontal Motions
–  Zonal winds flow nearly along latitude lines
–  Zonal winds within each cell band
•  DUE TO DEFLECTIONS BY CORIOLIS!
18
Atmospheric Circulation including
Coriolis R
Ferrel
EL
LA
Y F
ER
R
Active (updraft on hot
side, downdraft on cold
side)
PO
HADLE
3 Cells per hemisphere:
Polar
Passive (downdraft on
hot side!)
Hadley
Active
UCLA figure – background image unknown.
Atmospheric Circulation including
Coriolis
•  Latitudinal
winds:
–  0-30o: Trade
Winds
–  30-60o:
Westerlies
–  60-90o:
Polar
Easterlies
Figure by Hastings, Wikimedia Commons, Creative Commons A S-A 1.0 Generic,
http://en.wikipedia.org/wiki/File:AtmosphCirc2.png
19
Atmospheric Circulation including Coriolis
Cell Boundaries:
Polar Front
60o: Polar Front
Horse
Latitudes
30o: Horse
Latitudes
Doldrums
0o: Doldrums
Vertical air movement
(up at Polar Front
and Doldrums, down
at Horse Latitudes)
Figure by Hastings, Wikimedia Commons, Creative Commons A S-A 1.0 Generic,
http://en.wikipedia.org/wiki/File:AtmosphCirc2.png
Questions
Figure from NASA, Public Domain, http://sealevel.jpl.nasa.gov/overview/climate-climatic.html
20
Local Meteorology of Southern California
Marine layer against the Southern California mountains
Photo by Dr. Jonathan Alan Nourse, CalPoly Pomona,
http://geology.csupomona.edu/janourse/Storms,%20Floods,%20Landslides.htm
Mediterranean Climate
•  LA: Subtropical latitude, abutting ocean
•  Subsiding flow: sinking air
–  Clear most of the year
•  Effects of coast:
–  Higher humidity--- thermal buffer
•  Winter Storms
–  Pole-equator temp difference larger in winter
–  Speeds up jet stream, big storms get pushed our
way
21