Transcript 11-How-Climate-Works

Tuesday Oct 26th
SIT WITH YOUR GROUP TODAY
TOPIC # 12 HOW CLIMATE WORKS
I-3 IS DUE TODAY! Please deposit your I-3
WORKSHEET [STAPLED!] at the FRONT OF THE
CLASSROOM according to GROUP # (NOTE: we will
also accept Worksheets on Thursday if you don’t have yours
today or need it to finish your write-up tonight.)
The I-3 Write-Up is due in D2L Dropbox by 11:59 pm
tonight.
 As soon as you come in today, get
your GROUP FOLDER & finish up G-3 if
your group is not quite done . . . .
RQ-6 is due on THURSDAY Oct 28th
Warning: there is LOTS of reading
for this one!
TEST #3 is scheduled for a week
from TODAY. . . . . The Top 10 List will
be posted by Friday.
WRAP –UP of G-3 ASSIGNMENT
Applying the Energy Balance Terms
Your task is to decide which component or components
working together are most directly related to or
responsible for the observed phenomenon.
# 1 – #12 : Left side of equation
# 13 - #15: Right side of equation
p 53
THE G-3
ANSWERS
The LEFT side of the equation:
1.
gases of atmosphere
scatter shorter blue wavelengths
3.
2.
4. Noon: more
5.
+
& dusk: more
together = the Greenhouse Effect
6.
(dust, thicker atmosphere
scatters longer red/orange wavelengths)
7.
radiates day & night; camera senses IR
8.
9.
leads to distinct shadows,
while diffuse SW
radiation does not
10.
All wavelengths of visible part
of spectrum are scattered & transmitted in
a colored spectrum by raindrops
11.
Attempt to increase absorption &
reduce
into eyes; reduces glare
12. More
is absorbed, leads to more
which can then warm up car
The RIGHT Side of the Equation:
13. H
Hot air (less dense than surrounding
cool air) rises in a convection current & lifts balloon
14. Wet mud evaporates from pig & cools him: LE
also heat from pig’s body is conducted into soil:
15. June is hot & dry in Tucson.
Dry, hot air can
“hold” more water vapor, so water in cooler pads
is evaporated easily. Hence more energy goes
into
instead of
This cools the house!
LE
H
G
Topic # 12
How Climate Works
A “Primer” on
How the Energy Balance Drives
Atmospheric & Oceanic Circulation,
Natural Climatic Processes
pp 63-68 in Class Notes
How do we get energy from this . . . .
. . . . to drive this ?
. . . . or this ?
http://www.vets.ucar.edu/vg/T341/index.shtml
. . . .which leads to Global Climatic Regions:
. . . .and CHANGES in these regions!
Hotter!
Drier!
Wetter!
from Dire Predictions text
It all happens because of changes in
the RADIATION / ENERGY BALANCE !
“Radiation Balance” part
All components are
referring to modes of
heat energy transfer or
heat energy storage
involving matter
All components
are referring to
electromagnetic
radiation
“Energy Balance” part
Start out here,
with energy
from the SUN
radiated to
Earth and so
forth . . .
“Radiation Balance” part
=
The
is then able to
be used in thermal
energy “heat transfer” “Energy Balance” part
processes which
manifest themselves
as weather & climate!
Thermal Energy Review
Heat (def) = the thermal energy that is
transferred from one body to
another because of a temperature
difference.
• Sensible Heat transfer (H)
• Latent Heat transfer (LE)
plus (after transfer) thermal
energy can be STORED (G)
Review
ENERGY IN THE EARTH-ATMOSPHERE SYSTEM
Ultimate source
of energy is the
SUN (SW)
After
absorption of
SW, LW energy
is radiated in &
out by EARTH
& Atmosphere
Any
NET
(leftover)
energy
Goes into
the HEAT
TRANSFER
processes that
drive
WEATHER &
CLIMATE !
The Earth
[as viewed from space]
. . . has the organized, selfcontained look of a live creature,
full of information, marvelously
skilled in handling the sun.
~ Lewis Thomas
LINKING THE ENERGY
BALANCE TO ATMOSPHERIC
CIRCULATION . . .
We’ll start with the SUN
(SOLAR INSOLATION)
IN – SOL- ATION =
Amount of incoming solar energy
received by a point on Earth’s surface
p 63
To drive the circulation, the initial
source of energy is from the Sun:
EARTHSUN
Not to scale!
Relationships
4 Things to Know about Earth-Sun Relationships:
1) Earth orbits Sun in one year
2) Orbit is not a perfect circle ( = an ellipse )
3) Earth’s orbit around Sun can be “traced” on a plane
(“Plane of the Ecliptic” – plane passes thru the center of Sun & Earth)
4) Earth’s axis tilts 23.5  from a  to the “Plane of The Ecliptic”
http://mesoscale.agron.iastate.edu/agron206/animations/01_EarthSun.html
These 4 Earth-Sun Properties lead to:
the 2 factors that determine the
AMOUNT OF SOLAR INSOLATION
as the seasons progress:
(1) INTENSITY of sun’s rays
(perpendicular to surface = more intense)
(2) DURATION of daily insolation
(longer day length = more insolation)
p 63
Zenith point
changes with
latitude
A useful term:
ZENITH =
The point
directly
overhead
INTENSITY is
greatest at any
spot on Earth
when sun is
closest to the
ZENITH!

QUICKIE LATITUDE REVIEW:
90 N
66.5 N
23.5 N
0
23.5 S
66.5 S
90 S
EARTH-SUN RELATIONSHIPS
& The SEASONS:
VIEW THE ANIMATION:
http://mesoscale.agron.iastate.edu/agron206/animations/01_EarthSun.html
JUNE SOLSTICE
As viewed from one
side of Sun
JUNE SOLSTICE
As viewed from the
other side of the Sun
JUNE SOLSTICE
p 63
JUNE SOLSTICE
24 hours
of sunlight
Most
intense
solar
radiation
p 63
MARCH EQUINOX
Equinox =
“equal night”
p 79
SEPTEMBER EQUINOX
different seasonal position in orbit . . .
. . . but same latitudinal
insolation as March Equinox
MARCH & SEPTEMBER
EQUINOXES
12 hours
of sunlight
Most
intense
solar
radiation
p 63
DECEMBER SOLSTICE
DECEMBER SOLSTICE
24 hours of
darkness
Most
intense
solar
radiation
p 63
http://mesoscale.agron.iastate.edu/agron206/animations/01_EarthSun.html
Recap
THE RADIATION
BALANCE
& THE GENERAL
CIRCULATION OF THE
ATMOSPHERE
p 64
HOW IT ALL FITS TOGETHER:
Over the course of a year . . .
The amount of INCOMING
SW (Insolation) absorbed by
EARTH varies by LATITUDE
(MORE comes in near the
Equator, less near the Poles)
 LOW LATITUDES
absorb MORE energy
than HIGH LATITUDES
The amount of outgoing
TERRESTRIAL LW / IR
varies by latitude too --
MORE LW / IR is
emitted at warmer
LOW LATITUDES,
LESS in cooler
HIGH LATITUDES
HOWEVER . . .
p 64
The EQUATOR-POLE
DIFFERENCES of what
goes OUT from the
EARTH
are less than the
EQUATOR-POLE
DIFFERENCES of what
comes IN from the SUN
p 64
LESS SW
coming in
BUT the amount of
outgoing LW is only
slightly different from
latitude to latitude &
Equator to Pole
SW in < LW out
MORE SW coming in
SW in > LW out
p 64
The result is a NET
SURPLUS of energy in
the low latitudes & a
NET DEFICIT in the
high latitudes
p 64
POLE
EQUATOR
POLE
Now lets look at a
Pole to Pole Transect
p 64
Net radiation
deficit
Net radiation
surplus
Net radiation
deficit
What do the black & gray
areas represent?
(at top of atmosphere)
p 64
http://geography.uoregon.edu/envchange/clim_animations/
Global-scale air motions are driven
by thermal differences:
Northern Hemisphere
COLD
POLAR
REGIONS
EQUATOR
Southern Hemisphere
HOT
TROPICS
COLD
POLAR
REGIONS

COLD
POLAR
REGIONS
HOT
TROPICS
From SGC-I Chapter 4
COLD
POLAR
REGIONS
cold polar air
vs.
warm low lat air
sinking dry
subtropical air
rising tropical
warm,
moist air
sinking dry
subtropical air
warm low lat air
vs.
cold polar air
LOW PRESSURE AREAS:
Hot surface  Rising air
 expansion and cooling
of air, and condensation
of water vapor
 clouds, and
possibly
precipitation . . .
HUMID REGIONS

How do H2O droplets in warm,
tropical clouds coalesce and grow so
that they become heavy enough to
fall as rain in the ITCZ?

Mini-Zombie Break !
DANCE YOUR PH.D!
“Precipitation Initiation in Warm Clouds”
This dances shows how a rain drop can form
when one SLIGHTLY LARGER RAIN DROP is
present among a population of smaller drops.
In the tropics, really large drops (heavy enough
to fall as rain ) only form after mixing occurs.
Men are
Condensation
nuclei
Women are
H2O
droplets
In the “mixing process” the
H2O droplets connect with
“condensation nuclei partners”
. . . but eventually some H2O’s
abandon their original nuclei
for a larger one!
Through “coalescence”
a single nucleus attracts all
the other water droplets !
When the H2O droplet grows
large enough . . .
. . . RAIN FALLS!
http://www.youtube.com/watch?v=4O7G7F_e7I0
The opposite of rain = subsidence (sinking air)
In HIGH PRESSURE ares!
HIGH PRESSURE
AREAS:
Forced sinking
(e.g. in HADLEY CELL)
leads to “compaction” and
warming of the sinking air
Air warms  increase in the
water vapor holding capacity
 clear skies, dry air and
ARID REGIONS / DESERTS!

In general: Winds tend to flow from
HIGH  LOW Pressure areas

Subtropical
HIGH
PRESSURE
H
H
L
L
H
H
Intertropical
Convergence
ITCZ
Subtropical
HIGH
PRESSURE
p 64
BUT -Hadley cell
circulation does
not reach high
latitudes!
HADLEY
CELLS =
key drivers!
BUT –
Hadley cell
circulation
does not reach
high latitudes!
Convection cell
transfer of
thermal energy
from low
latitude area of
energy
SURPLUS to
higher latitude
area of energy
DEFICIT
p 64
Why Hadley convective
cell transport breaks
down at higher latitudes:
64
UPPER LEVEL CIRCUMPOLAR WINDS !
“Wave” transport of thermal energy
instead of Hadley cell transport! p 65
Hadley Cells are
only efficient in
transporting
energy to the
mid-latitudes
Hadley Cells +
Rossby Waves
together are
needed!
Energy is transported from areas of surplus to deficit in
form of:
(sensible heat) &
(latent energy)
IN TWO MAIN WAYS:
Atmospheric circulation moves warm & cold
air north & south across latitudes
H2O condenses in high
latitudes LE  H
H2O is evaporated in
low latitudes H  LE
p 65
The Community Climate System Model (CCSM)
is a coupled climate model for simulating Earth's climate system.
It simulates the earth's atmosphere, ocean, land surface and sea-ice
water vapor = WHITE
precipitation rate = ORANGE.
http://www.vets.ucar.edu/vg/T341/index.shtml
Net radiation
deficit
Net radiation
surplus
(at top of atmosphere)
Net radiation
deficit
p 64
THERMAL ENERGY IS TRANSPORTED
FROM LOW  TO HIGH LATITUDES
TO BALANCE OUT THE DEFICIT! p 64
BUT WHAT ABOUT G ?
G is a STORAGE component, not a transfer
component BUT energy stored in the OCEAN, can
later be transported via ocean currents as H !
WARM & COLD SURFACE OCEAN CURRENTS:
97
p P66
 Large OCEAN GYRES -- driven by Trade
Winds & Westerlies in Oceanic Subtropical
HIGH PRESSURE CELLS (STH)
Leads to SURFACE ocean currents
H
H
H
H
H
H
97
pP66
Energy is transported from areas of surplus to deficit via:
H (sensible heat)
&
LE (Latent Energy)
p 65
Both ATMOSPHERE & OCEAN play
important roles in BALANCING OUT
ENERGY SURPLUS & DEFICIT AREAS:
ATMOSPHERE more
important in
mid  high latitudes
OCEAN
transports
MOST of
the energy
in LOW 
subtropical
latitudes
Poleward transport of energy in N.H.
P 67
ZOMBIE
BREAK !
Turn to
Page 30
in Class
Notes . . . .
As you watch the segments of this film . . . .
Check off the changes
on p 30 in CLASS NOTES :
Checklist of Direct Observations of
Recent Climate Change:
etc., etc.
p 30
Watch the video carefully
– at some point a
feedback loop
process is described.
Can you recognize it ???
(HINT: it is one of the loops
shown on p 56 in Class Notes)
Make a note of it . . . . .
AFTER THE FILM: GROUP BONUS
POINT CHALLENGE - PART 1:
State which feedback loop was
described in the film and sketch the
FEEDBACK DIAGRAM for it on one side
of the INDEX CARD provided.
GROUP BONUS
POINT CHALLENGE
- PART 2:
NOW – on the back of
the index card, as a
group, complete the
feedback loop on the
bottom of page 58 by
linking the components
with the proper
coupling arrow symbols
as used in the SGC text
p 58
albedo
Extent of
ice cover
Amount of
melting
SW
radiation
absorbed
Ocean
temperature
The
ANSWER!
+
albedo
Extent of
ice cover
-
Amount of
melting
+
-
-
SW
radiation
absorbed
+
+
Ocean
temperature
SNOW AND ICE ALBEDO
Feedback

BE SURE TO REVIEW THE
CLASS FOLLOW-UP IF YOU
WANT TO GO OVER THESE
ANSWERS AGAIN . . . . .
See you on Thursday – don’t
forget RQ-6!