ess15 lecture 10 - uci sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...the...
TRANSCRIPT
![Page 1: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/1.jpg)
ESS15 Lecture 10Winds and weather The Coriolis force
Global circulations of atmosphere & ocean Weather vs. Climate
Earth’s energy imbalances, winds, and the global circulation of the atmopshere.
Please read Chapter 6 from Archer Textbook
![Page 2: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/2.jpg)
Theforestandthetrees. Wherewearesofar.
• To appreciate future climate change we need to understand climate.
• Climate is place and energy flows.
• What forces sculpt it to be the way it is?
• Until we get this, it’s pointless for me to lecture about carbon taxes and coal plants.
• We’re getting very close!
![Page 3: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/3.jpg)
• Why surfers get up early in the morning.
• Why it doesn’t rain much in the O.C.
• Origins of a mysterious geographic pattern in where Earth’s deserts are located.
Today’s lecture will give you an in depth appreciation for:
![Page 4: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/4.jpg)
Energy balance of the whole Earth.
![Page 5: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/5.jpg)
But nobody lives on the “whole Earth”.
![Page 6: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/6.jpg)
To understand why OC’s climate is different than other locations, need to look at energy
imbalances within the planet.
![Page 7: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/7.jpg)
First, we need to remember how to navigate around Earth.
![Page 8: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/8.jpg)
negative latitude
positive latitude
0
Latitude of zero is at the equator.
Common unit:deg N
Navigating the planet - latitude.
![Page 9: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/9.jpg)
Increasinglongitude.
Longitude of zero is near England
Common unit:deg E
Navigating the planet - longitude.
![Page 10: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/10.jpg)
Specific locations on the Earth’s surface correspond to unique (lat, lon) coordinates.
Increasinglongitude.
negative latitude
0
This location’s coordinates are ~(30 deg N, 200 deg E)
![Page 11: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/11.jpg)
Maps are data (numbers) visualized as colors at different latitude, longitude coordinates.
![Page 12: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/12.jpg)
Example: Map of surface elevation.
Blue: low values
(low places)
Red: high values (tall places)
Green: in between values
Increasing longitude
Incr
easi
ng la
titud
e
![Page 13: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/13.jpg)
Example - map of vegetation amount.Brown:
low values (deserts)
Green: high values
(forests)
![Page 14: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/14.jpg)
Cool fact: there’s a planetary scale “latitudinal” pattern to where the Earth’s deserts occur!
equatorwet wet wet
drydrydry
dry dry
~ 30 deg N
~ 30 deg S
You are here
![Page 15: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/15.jpg)
Cool fact: there’s a planetary scale “latitudinal” pattern to where the Earth’s deserts occur!
wet drydryEQ 30N30SIncreasing latitude
Has everything to do with what causes this mysterious global pattern.
Ever wonder: Why doesn’t it rain very much in the O.C.?
Stay tuned for a scientifically accurate rap!
Pattern:
![Page 16: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/16.jpg)
Energy imbalances in the planet.
![Page 17: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/17.jpg)
At low latitudes, near the equator, sun rays strike the earth surface more perpendicularly, so more Watts are absorbed there than at the poles.
This is called “differential forcing” —> different solar radiation absorbed at different latitudes.
![Page 18: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/18.jpg)
The principle is the same as why solar panels track the sun to absorb maximum Watts by staying perpendicular to its rays.
![Page 19: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/19.jpg)
Energy balance is different in different places!
• To see this, useful to map “net” radiation.
• Definition: “Net” radiation
• Solar in minus longwave out (W/m2)
• If positive: More Watts from sun than Watts out to space —> energy constantly building up.
• If negative: More Watts cooling to space than coming in from sun —> energy constantly being lost.
![Page 20: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/20.jpg)
Observed energy Imbalances
Circulation of the atmosphere and oceans are driven by energy imbalances
![Page 21: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/21.jpg)
Energy Imbalances
![Page 22: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/22.jpg)
Winds and Weather and the atmospheric
circulation.
![Page 23: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/23.jpg)
• Objects stay put or move uniformly in the same direction unless acted on by a force
• Acceleration is a result of the sum (net) of forces, in the vector sense
Isaac Newton
![Page 24: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/24.jpg)
• Three real forces
(gravity, pressure gradient, & friction) push the air around
• Two apparent forces due to rotation
• (Coriolis and centrifugal)
• Large-scale flow is dominated by gravity/pressure and Coriolis … friction and centrifugal are also important locally
What makes the wind blow?
![Page 25: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/25.jpg)
Forces acting on the air.
Pressure gradient force (pushing)
![Page 26: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/26.jpg)
Air is pushed from regions of higher to lower pressure - makes a wind.
• Pressure gradient force makes the wind
• (think bike tire leak)
![Page 27: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/27.jpg)
i-clicker survey.Why doesn’t higher pressure air at sea level get blown up to lower pressure air at the top of Mount Whitney?
• A: Gravity
• B: Friction
• C: The Coriolis force
• D: All of the above.Al
titud
e (k
m)
high pressure
low pressure
![Page 28: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/28.jpg)
Forces acting on the air.
Pressure gradient force Gravity
(falling)Friction
(rubbing against the surface)
Apparent forces:
Coriolis force Centrifugal
force
![Page 29: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/29.jpg)
Whydoespressure varyhorizontally?
• Elevation changes cause pressure differences
• These are balanced by gravity and don’t cause wind to blow
• Butwhydoespressurevarybetweenloca3onswhichareatthesameeleva3on?
P1
P2
![Page 30: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/30.jpg)
Why does pressure vary horizontally?
![Page 31: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/31.jpg)
ThoughtExperiment:Considertwocolumnsofairwiththe
sametemperatureanddistributionofmass
1000mb 1000mb
500mblevel
![Page 32: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/32.jpg)
Nowcooltheleftcolumn
andheattheright
1000mb
500mb
500mb
1000mb
Theheatedcolumnexpands
Thecooledcolumncontracts
original500mblevel
![Page 33: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/33.jpg)
Heightofthe500mbsurfacechanges;thesurfacepressureisunchanged
1000 mb
new 500 mb level in warm air
new 500 mb level in cold air
1000 mb
The 500 mb surface is displaced upward in the warmer column
The level corresponding to 500 mb is displaced downward in the cooler column
original 500 mb level
The surface pressure remains the same since both columns still contain the same mass of air.
![Page 34: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/34.jpg)
1000 mb
new 500 mb level in warm air
new 500 mb level in cold air
1000 mb
The 500 mb surface is displaced upward in the warmer column
The 500 mb surface is displaced downward in the cooler column
original 500 mb level
The surface pressure remains the same since both columns still contain the same mass of air.
A pressure difference in the horizontal direction develops above the surface
HighLow
![Page 35: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/35.jpg)
1003 mb 997 mb
original 500 mb level
Air moves from high to low pressure in the middle of the column,
causing the surface pressure to change.
HighLow
![Page 36: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/36.jpg)
1003 mb 997 mb
original 500 mb level
So air moves from high to low pressure at the surface…
HighLow
High Low
Where would we have rising motion?
![Page 37: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/37.jpg)
Thought Experiment Review
• Starting with a uniform atmosphere at rest, we introduced differential heating
• The differential heating caused different rates of expansion in the fluid
• The differing rates of expansion resulted in pressure differences aloft along a horizontal surface.
• The pressure differences then induced flow (wind!) in the fluid
• The convective circulation cell transfers heat away from the hotter column and towards the colder column.
![Page 38: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/38.jpg)
This is a microcosm of how the atmosphere converts differential heating into motion
![Page 39: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/39.jpg)
Local example of a thermal circulation cell – theday8mecoastalseabreeze.
A: OCEAN B: LAND
i-clicker: Which air heats up faster during the day, the stuff over (A) the ocean or (B) the land?
Solar radiation
![Page 40: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/40.jpg)
Local example of a thermal circulation cell – theday8mecoastalseabreeze.
A: OCEAN B: LAND
Solar radiation
More heatingLess heating
In other words, “differential heating” of air across the coastline.
![Page 41: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/41.jpg)
Local example of a thermal circulation cell – theday8mecoastalseabreeze.
That is, the circulation cell moves heat energy from the hotter to the colder place.
![Page 42: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/42.jpg)
i-clickersurvey
Which way does the coastal sea breeze blow in day / night?
a. land àocean / land à ocean b. land à ocean / ocean à land c. ocean à land / ocean à land
d. ocean à land / land à ocean e. there is no rule on it!
![Page 43: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/43.jpg)
![Page 44: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/44.jpg)
The atmosphere uses circulation cells to counteract energy imbalances in the air across coastlines. Produces offshore winds in the night / early AM.
So, surfers get up early in the morning because
![Page 45: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/45.jpg)
And where’s my professor rap about why it doesn’t rain in the O.C.?
Ok, but how on Earth does this stuff relate to the question why there’s a global geographic pattern in deserts?
![Page 46: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/46.jpg)
Recall “Differential heating” also happens on planetary scales.
![Page 47: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/47.jpg)
Energy Imbalances from differential heating
![Page 48: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/48.jpg)
IftheEarthdidn’trotate,itwouldbeeasyfortheglobalflowofairtobalancetheenergythroughathermalcircula8oncell.
• Thermal convection would lead to formation of convection cell in each hemisphere
• Energy transported from equator toward poles
• Surface wind in Irvine would always blow from the North
What it would look like if the planetary wind patterns looked like a coastal cell.
![Page 49: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/49.jpg)
ButtheEarthdoesrotate–aCoriolisforce.AndthisreallymaHerstotheglobalcircula8on!
We live underneath a descending branch of The Hadley Cell
![Page 50: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/50.jpg)
wet drydryEQ 30N30S Increasing
latitudePattern:
The pattern of the Hadley Cell explains why the deserts are where they are.
![Page 51: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/51.jpg)
• Differential forcing (different solar radiation at different latitudes) drives energy imbalances in the Earth system.
• The air tries to move the heat poleward via a thermal circulation cell.
• But because the Earth is spinning and the result is a Hadley cell with descending, dry air near 30S & 30 N.
• That’s why it doesn’t rain much in the OC.
• That’s why most deserts are located at similar latitudes.
Why it doesn’t rain in the O.C. (science)
![Page 52: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/52.jpg)
Why it doesn’t rain in the O.C (hip hop)
• Best believe my science tight i’m talking differential forcing
• (Different solar radiation that the latitudes absorbing)
• - add the fact the Earth be spinning Hadley circulation soaring
• Up in tropics, down in O.C. that’s the reason it ain’t pouring.
![Page 53: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/53.jpg)
Why it doesn’t rain in the O.C (hip hop)
• Best believe my science tight i’m talking differential forcing
• (Different solar radiation that the latitudes absorbing)
• - add the fact the Earth be spinning Hadley circulation soaring
• Up in tropics, down in O.C. that’s the reason it ain’t pouring.
![Page 54: ESS15 Lecture 10 - UCI Sitessites.uci.edu › ess15winter2016 › files › 2016 › 02 › ...The forest and the trees. Where we are so far. • To appreciate future climate change](https://reader033.vdocuments.us/reader033/viewer/2022060417/5f146e77bba29f2de04ebb66/html5/thumbnails/54.jpg)
Next time: The Coriolis force.
Thanks.