Transcript Document
ORIGIN AND COMPOSITION OF
THE ATMOSPHERE
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THE BIRTH OF THE EARTH: ACCRETION OF PLANETESIMALS
5·109 years
Planetesimals are objects of some Km of diameters that are thought to have formed during
the solar system's formation.
The origin of the Solar System has been tracked by Safronov's theory about 5 billion years
ago, when an initial primordial nebula made of gas (mostly hydrogen and helium) and very
diffuse dust grains (carbon and silicate) started to collapse gravitationally leading to the
formation of a central protostar and of a surrounding, rotating disk structure, made from the
material that was not incorporated in the protostar. During this disk phase (that can last up
to 100 millions years), the grains of dust grow in size very rapidly (this phenomenon being
called accretion) until, after a relatively short period, they form planetesimals. These
planetseimals have a composition that depends on the region where they have formed (we
find rocky planetesimals in the inner parts and ices in the outer parts) and are the "bricks" of
the following formation of the planets. In fact in the last phase, the accretion of planets is
possible, due to the impacts between planetesimals that can glue together, forming growing
objects with a composition that is still respected by the actual structure of the solar system
(where, in the inner parts, wet find rocky planets, while in the outer parts, planets are
gaseous).
Asteroids and comets are leftover planetesimals that have not been incorporated into a
planet during this period.
http://www.ecology.com/archived-links/planetesimals/
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THE INNER STRUCTURE OF THE EARTH
Structural diferentiation
according to the density
of different materials
Inner core
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Main component: Iron
Solid, radius 1200 km
External core Main component: Iron
Líquid, radius 3470 km
Mantle
Iron, magnesium,
aluminium, silicon
and oxigen
Radius 3470 km
Adapted from:
http://zebu.uoregon.edu/internet/images/earthstruc.gif
Crust
Sodium and aluminium
silicate minerals
Thickness 8 - 70 km
http://www.seismo.unr.edu/ftp/pub/louie/class/100/interior.html
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THE ORIGIN OF OUR ATMOSPHERE
Originally formed by volatile compounds from volcanism at the earlier period of the Earth’s
story. The gasses were kept back by gravity force. Since then, its composition undergone
important variations because several physical, geological and biological processes.
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Actual volcanic eruptions have a mean composition of 85% H2O, 10% CO2 and SO2 and
nitrogen compounds (the rest).
Low percentage of H2O in the actual atmosphere
Low percentage of CO2 in the actual atmosphere
We have to explain…
Predominance of nitrogen
Presence of other components of low concentration
Presence of an important fraction of O2
http://www.xtec.es/~rmolins1/solar/es/planeta02.htm
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COMPOSITION OF THE ATMOSPHERE
Componentes
mayoritarios
atmósfera
Dry air (majority
components)
(% volumen)
Composition below 100
km (percentages)
N2 78%
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O2 21%
Ar 0.93%
Dry air (majority component)
(% mass)
N2 76%
Otros 0.04%
O2 23%
Ar 1.3%
Water steam:
Until 4% (volum)
Otros 0.07%
Adaptad from John M. Wallace y Peter V. Hobbs, Atmospheric Science: an introductory survey. Academic Press
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COMPOSITION OF THE ATMOSPHERE (CONTINUED)
(parts per million)
Minority components
CO2 325 ppm (93%)
Ne 18 ppm
(5.2%)
He 5 ppm (77%)
Resto 6.5 ppm
(1.9%)
Kr 1 ppm
(15%)
H2 0.5 ppm
(7.7%)
Ozone: 0-12 ppm
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WATER IN THE ATMOSPHERE
Low contents of water in the actual atmosphere
mb
40
P
30
Room
conditions
23 mb
20
10
Both axis have
not the same
scale
ºC
10
20
30
PC
T3= 0.01 C = 273.16 K
P3= 0.006112 bar
1 atm
P3
TC = 374.15 C = 647.30 K
PC = 221.20 bar
T3
100 C
TC
T
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WATER IN THE ATMOSPHERE (CONTINUED)
Low atmospheric contents in water
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Limited ability to keep water steam in the air
Saturation and condensation
Precipitation and formation of the oceans
Hydrosphere
Interdependence of the system
atmosphere / hydrosphere
http://matap.dmae.upm.es/Astrobiologia/Curso_online_UPC/capitulo11/3.html
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HYDROSPHERE
Mass 1.36·1021 kg
97%
Oceans
Ice
Subsoil
Rivers & lakes
Atmosphere
Océano 97%
Hielo 2.4%
97 %
2,4 %
0,6 %
0,02 %
0,001 %
Otros 0.6%
97
2,4
0,6
Subsuelo 97%
97%
2.4%
0.6%
The actual water content of the hydrosphere is
two magnitude orders LOWER than that have
been injected into from the origin ot the Earth
Ríos y lagos 3,3%
How to explain this shortfall?
Atmósfera 1,7%
3.3%
0.17%
* Filtration at subduction points
* UV fotodisociation
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http://geology.er.usgs.gov/eastern/plates.html
The earth's surface is broken into seven large and many small moving plates. These plates, each about 50 miles
thick, move relative to one another an average of a few inches a year.
At convergent boundaries, plates move toward each other and collide. Where an oceanic plate collides with a
continental plate, the oceanic plate tips down and slides beneath the continental plate forming a deep ocean trench
(long, narrow, deep basin.) An example of this type of movement, called subduction, occurs at the boundary
between the oceanic Nazca Plate and the continental South American Plate. Where continental plates collide, they
form major mountain systems such as the Himalayas.
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HYDROSPHERE. SUBDUCTION
Subduction
(oceanic
trench)
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Ocean
Oceanic crust
Continental crust
Upper mantle
Filtrations towards the mantle
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HYDROSPHERE. WATER FOTODISOCIATION
Molecule of water
Fotodisociation
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High atmosphere, low pressure conditions
H
H
UV high energy photons
O
H
H
O
H
O
H
H
O
104º
H
High energy photons arise highly reactive free
radicals, which recombinate as new chemical
species.
Specially hidrogen tends to run away because its
low molecular mass.
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CARBON DIOXIDE IN THE ATMOSPHERE
Low rate of carbon dioxide
Estimation of carbon content
in the Earth crust
(relative units)
Geological and biological porcesses
Storing of carbon:
* Rocks, salts, fossil oils
* Atmosphere (free CO2) and ocean (solved CO2
* Biosphere
Oxigen presence in the crust:
* Iron salts, carbonates y bicarbonates
Marine biosphere
Continental biosphere
Atmosphere (CO2)
Ocean (solved CO2)
Fossil oils
Salts
Carbonates
1
1
70
4000
800
800000
2000000
Source: John M. Wallace y Peter V. Hobbs,
Atmospheric Science: an introductory survey.
Academic Press.
From P K Weyl, Oceanography.
John Wiley & Sons, NY, 1970
Carbonates: arising by ionic exchange
reactions (living beings)
H2O + CO2 H2CO3
H2CO3 + Ca++ CaCO3 + 2H +
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HUMAN ACTIVITY AND CO2 ATMOSFERIC CONTENT
Concentration
CO2 (ppm)
335
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330
325
320
315
1958
1960
1962
1964
1966
1968
1970
Año
1972
1974
Data from Mauna Loa observatory (Hawaii).
Adapted from John M. Wallace y Peter V. Hobbs, Atmospheric Science: an introductory survey.
Concentration increasing from 1750
29%
280 ppm
1750
360 ppm
Actual
Based on
http://zebu.uoregon.edu/1998/es202/l13.html
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NITROGEN AND MINORITARY COMPONENTS
Atmospheric predominance of N2
The nitrogen content has been only slightly changed because its low reactivity
Around 20% fixed as nitrates (biological activity)
Other components of the atmosphere
Acid rain
SULPHUR: injected by volcanoes
Sulphates in crust
NOBLE GASES: He, Ar
From radiactive desintegrations
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OXIGEN
SOURCES OF THE ATMOSPHERIC OXIGEN
Water disociation (UV)
2H2O 2H2 + O2
Photosynthesis (visible light)
H2O + CO2 {CH2O} + O2
Earlier living beings
(reducing environment) *
4109 años
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Increased O2 releasing
4108 years
LIFE IN
THE OCEANS
Unicelular seaweed
releasing O2
2-3109 años
*
O2 PRESENCE IN THE
ATMOSPHERE AS A
CONSEQUENCE OF
BIOLOGICAL PROCESSES
LIFE ON THE SURFACE
Formation O3
Decreasing UV
radiation in surface
See Miller’s experiment in
http://matap.dmae.upm.es/Astrobiologia/Curso_online_UPC/capitulo9/4.html
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ATMOSPHERIC PRESSURE
Fluids equation:
dp g
dz
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The air density decreases as height increses
z
Vertical variation >> horizontal variation
Below 100 km, for every height from the ground, pressure lies
within an interval of 30% of a standard value.
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ATMOSPHERIC PRESSURE (CONTINUED)
dP g
dz
Air is a compressible fluid
Density and pressure are proportional
BP
z
dP BPg
dz
dP Bg dz
P
z
Ln P Bg z
P0
H
P
z
P0
0
dP
P Bg dz
H 1
Bg
It depends on the molecular mass of the gas
P P0 exp( z / H )
H 7 km
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ATMOSPHERIC PRESSURE (EXAMPLE)
Mount Everest is the highest mountain in the Earth (8848 m). Explain which
calculations may be performed to obtain the pressure on its top.
Compare this pressure with the pressure in the seabed at 8848 m depth.
Assume conditions of constant temperature.
Data: Air density: 1.225 kg/m3; marine water density: 1030 kg/m3.
Pressure and density are proportional
Ground level:
0 BP0
0
1.225 kg/m 3
5
2
Hence we estimate a value for B: B
1
.
209
10
(s/m)
P0 1.01325 105 Pa
Ground level standard pressure
Remember that...
P P0 exp( z / H )
1
H 1
8432 m
Bg 1.209 105 9.81
P 1.01325 105 exp(8848 / 8432) 35481 Pa 354.8 mb
From standard atmosphere calculator: P = 314.4 mb
http://www.digitaldutch.com/atmoscalc/
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ATMOSPHERIC PRESSURE (EXAMPLE CONTINUED)
Mount Everest is the highest mountain in the Earth (8848 m). Explain which
calculations may be performed to obtain the pressure on its top.
Compare this pressure with the pressure in the seabed at 8848 m depth.
Assume conditions of constant temperature.
Data: Air density: 1.225 kg/m3; marine water density: 1030 kg/m3.
Calculus from standard atmosphere
T 288.15 6.5 z
288.15
P 1013.25
T
z given in km, T given in K
5.256
Our calculus:
P P0 exp( z / H )
P 1013.25 exp( z / 8432)
z (m)
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
5500
6000
6500
7000
7500
8000
8500
8848
9000
9500
10000
10500
11000
z (km)
0,0
0,5
1,0
1,5
2,0
2,5
3,0
3,5
4,0
4,5
5,0
5,5
6,0
6,5
7,0
7,5
8,0
8,5
8,8
9,0
9,5
10,0
10,5
11,0
T (K)
288,2
284,9
281,7
278,4
275,2
271,9
268,7
265,4
262,2
258,9
255,7
252,4
249,2
245,9
242,7
239,4
236,2
232,9
230,6
229,7
226,4
223,2
219,9
216,7
P (mb)
St. Atm.
1013,3
954,6
898,7
845,6
794,9
746,8
701,1
657,6
616,4
577,3
540,2
505,1
471,8
440,3
410,6
382,5
356,0
331,0
314,4
307,4
285,2
264,4
244,7
226,3
P (mb)
Ours
1013,3
954,9
899,9
848,1
799,3
753,3
709,9
669,0
630,5
594,2
560,0
527,8
497,4
468,7
441,8
416,3
392,3
369,8
354,8
348,5
328,4
309,5
291,7
274,9
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ATMOSPHERIC PRESSURE (EXAMPLE CONTINUED)
Mount Everest is the highest mountain in the Earth (8848 m). Explain which
calculations may be performed to obtain the pressure on its top.
Compare this pressure with the pressure in the seabed at 8848 m depth.
Assume conditions of constant temperature.
Data: Air density: 1.225 kg/m3; marine water density: 1030 kg/m3.
1200,0
1000,0
P (mb)
800,0
600,0
400,0
Standard atmosphere
200,0
Exponential dropping
0,0
0,0
2,0
4,0
6,0
z (km )
8,0
10,0
12,0
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ATMOSPHERIC PRESSURE (EXAMPLE CONTINUED)
Mount Everest is the highest mountain in the Earth (8848 m). Explain which
calculations may be performed to obtain the pressure on its top.
Compare this pressure with the pressure in the seabed at 8848 m depth.
Assume conditions of constant temperature.
Data: Air density: 1.225 kg/m3; marine water density: 1030 kg/m3.
Comparison: pressure on the Everest top and pressure on the bottom of the sea
Everest top
8848 m
Pressure on the top
P = 314.4 mb
(from standard atmosphere)
P = 354.8 mb
The pressure exerted by a water column of height z is
(from our calculus)
P w gz 1030 9.8 8848
Oceanic trench
Pressure on the bottom
P 8.93 107 Pa 893 bar
22
-8848 m
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ATMOSPHERIC LAYERS
1% rest
Termosphere
MESOPAUSE
99% rest
Mesosphere
80 km
Charged particles (ionosphere)
50 km
ESTRATOPAUSE
Estratosphere
99.9% mass
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Charged and non-charged particles
Scarce collisions
Very dry, O3 main concentration zone
High times of permanence of particles
Vertical mixture is scarce
TROPOPAUSE
10 - 12 km
grad T -7 K·km-1
Troposphere
80% mass, 100% water steam
Short times of permanence of particles
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TROPOPAUSE HEIGHT
Factors affecting the height of the tropopause
Estratosphere
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* Latitude
Over the equator the tropopause
lies higher than upon the poles
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Graphics obtained using yearly mean data from
http://www-das.uwyo.edu/~geerts/cwx/notes/chap01/tropo.html
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Additional information:
Map of tropopause pressures (mean values 1983-1998)
http://www.gfdl.noaa.gov/~tjr/TROPO/TROPO.html
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Altura (km)
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12
* The season of the year
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Troposphere
8
* Temperature in troposphere
6
-80
-60
-40
-20
0
20
40
60
80
Latitud (grados)
When temperature is low, the
tropopause goes down because
the convection decreases.
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STANDARD ATMOSPHERE
•
•
•
•
Air temperatura at height 0 (sea level) is 15 ºC (288.15 K)
Air pressure at height 0 is 1013.25 hPa
Atmospheric air is considered as dry air and it behaves as an ideal gas
Gravity acceleration is constant and its value is 980.665 cm/s2
•
From sea level until 11 km the temperature decreases as height increases at a rate
of 6.5 ºC/km: T = 288.15 K -( 6.5 K/km)· H (H: height in km)
Throughout this layer pressure is calculated by P = 1013.25 hPa ·(288.15 K/T)^5.256
•
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•
•
From 11 to 20 km the temperature remains constant: 216.65 K
Throughout this layer pressure is calculated by P = 226.32 hPa · exp(-0,1577·(H11km))
•
From 20 to 32 km the temperature increases: T = 216.65 K + (H-20 km) (H: height
in km)
Throughout this layer pressure is calculated by
P = 54.75 hPa·(216.65K/T)^34.16319
•
•
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STANDARD ATMOSPHERE (CONTINUED)
•
•
•
•
From 32 to 47 km the temperature increases as height increases:
T = 228.65 K + (2.8 K/km)·(H-32 km) (H: height in km)
Throughout this layer pressure is calculated by
P = 8.68 hPa · (228.65 K/T)^12.2011
•
•
•
From 47 to 51 km the temperature remains constant at 270.65 K
Throughout this layer pressure is calculated by
P = 1.109 hPa · exp(-0,1262·(H-47km))
•
The rest of upper levels can be obtained from the following references: A. Naya
(Meteorología Superior en Espasa-Calpe); y, R.B.Stull (Meteorology for Scientists
and Engineers)).
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Source: J. Almorox, http://www.eda.etsia.upm.es/climatologia/Presion/atmosferaestandar.htm
Standard atmosphere calculator:
(until 86 km): http://www.digitaldutch.com/atmoscalc/
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STANDARD ATMOSPHERE. PRESSURE PROFILE
160
Height
(km)
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140
120
100
Pressure (mb)
Density (g/m3)
Mean free path (m)
Liquid water
at room
conditions
106 g/m3
80
60
40
Mean path a molecule goes
over before colliding another
20
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
1
Graphic according with data from
John M. Wallace y Peter V. Hobbs, Atmospheric Science: an introductory survey. Academic Press
Adapted from CRC Handbook of Chemistry and Physics, 54th Edition. CRC Press (1973)
10
102
103
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STANDARD ATMOSPHERE. TEMPERATURE PROFILE
Exosphere
520
510
500
TERMOPAUSE
490
H
e
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h
t
160
Temperature of
termosphere is highly
dependent on sun
activity. It may vary
from 500 ºC to 1500 ºC.
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Termosphere
150
We live here!
140
(km) 130
120
110
100
90
MESOPAUSE
80
70
Mesosphere
60
50
STRATOPAUSE
40
Stratosphere
30
20
10
TROPOPAUSE
Troposphere
-100
-50
0
50
100
150
200
500/1500
Temperature (ºC)
28
Graphics from data in http://www.windows.ucar.edu/tour/link=/earth/images/profile_jpg_image.html
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ATMOSPHERE COMPOSITION AS A FUNCTION OF HEIGHT
The atmosphere composition varies as the height increases because the following reasons:
1. Diffusion by aleatory molecular movements
Diffusion tends to yield an atmosphere in which the mean molecular mass of the
mixture components decreases as height increases.
Each gas behaves in the same way as whether it were the only component in the
mixture (ideal behaviour), and the density of each decreases exponentially as height
increases.
However the reference height H is different for each gas, and so the gasses having
lower molecular mass are most abundant at the upper levels, because the density of
the lighter gasses drops slower than that of the heavier gasses.
H
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h
t
H 1
Bg
P P0 exp( z / H )
Could you demonstrate that really higher M implies higher B?
Higher M, Higher B
Lower H
P
Lower M, lower B
Higher H
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ATMOSPHERE COMPOSITION AS A FUNCTION OF HEIGHT (CONTINUED)
2. Mixture for convection
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Convection tends to homogenize the composition of the atmosphere. At low
levels the mean free path is very small, so the time required for pulling
apart different components is much larger than the time the turbulences
take for arising a homogeneous mixture.
Mean free path vs height
160
As a consequence, at low levels the
atmosphere is a system well stirred
whose components are very well
mixed.
km
140
120
The limit is about 100 km
100
80
Above 100 km the mixture by
convection is no longer as efficient
as it was below, and it appears a
difference in composition
depending on the height.
60
40
m
20
10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1 1
10
102
103
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LOSE OF GASSES FROM THE ATMOSPHERE
Boltzmann constant
k = 1.38·10-23 J K-1
Most probable velocity:
v
T: Absolute temperature
2kT
M m
m: Mass of the hidrogen atom
E
M: Molecular weight of a particular gas species n
v
Escape velocity: that velocity in what the kinetic energy of a particle is big enough
i
to run away towards the infinitum.
r
( At a height of 500 km, the escape velocity from the Earth is about 11 kms-1)
o
n
m
Temperature at 500 km is 600 ºC
Most probable velocity 3 kms-1
e
n
t
Fraction of molecules with velocity equal to escape velocity
a
l
Most probable velocity
Hidrogen 3 kms-1
10 -6
Oxigen 0.8 kms-1
10 -84
The lighter gasses did escape along the geological eras, so its actual abundance is low
http://www.iitap.iastate.edu/gccourse/chem/evol/evol_lecture.html
31
P
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WIND
Wind is the moving air from one place to another over the Earth surface.
The air flux is related (among other causes) with pressure differences.
The change in pressure measured
across a given distance is called a
pressure gradient.
Pressure is
a scalar
magnitude
Pressure gradient
P
ur
r
+
GRADIENT DIRECTION:
THAT OF FASTER VARIATION OF THE SCALAR MAGNITUDE
1016
1020
The air tends
to move
against the
pressure
gradient
grad P
1024
ur
-grad P
Blue arrows indicate
the sense opposite to
that of the gradient
pressure
Do we conclude
that wind moves
as the blue
arrows show?
GRADIENT SENSE:
TOWARDS HIGHER VALUES OF THE MAGNITUDE
NO! …we need also consider the rotation of the Earth!
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E
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P
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EARTH ROTATION EFFECTS
North
Pole
a aR 2 vR r
E
Centripetal force n
2 vR
v
Coriolis
2 vR
vR
i
Acceleration measured
r
in a rotating reference frame
o
n
m
Acceleration measured
e
in an inertial reference frame
n
aR a 2 vR r
t
a
Trajectory within an inertial reference frame
l
Trajectory within an accelerating reference frame
Within an rotating reference frame
a Coriolis force proportional to
2 vR appears, beeing responsible
for the observed deviation
2 vR
vR
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CORIOLIS DEVIATION
Seen from a point over the surface
N
NORTHERN HEMISPHERE
2 vR
2 vR
vR
Deviation on the right-hand side
respect the sense of the movement
2 vR
S
vR
2 vR
Deviation on the left-hand side
respect the sense of the movement
E
n
v
i
r
o
Coriolis deviation
n
m
e
SOUTHERN HEMISPHERE n
t
a
l
Coriolis
P
deviation
h
Sense of the
y
movement
s
i
c
34
s
Sense of the movement
GEOSTROPHIC WINDS
Remember: if the Earth would not spin around its polar axis, the movement of the
air masses will occur in the opposite sense to that the pressure gradient.
E
n
v
Pressure gradient
i
r
o
n
m
e
n
t
… and so on, up to the situation is… a
l
Geostrophic winds: winds balanced by the Coriolis and Pressure Gradient forces
Northern hemisphere
B
Gradient force
-grad P
Coriolis force, proportional to 2 vR
B
A
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/geos.rxml
A
…geostrophic winds blowing parallel to isobars
35
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ANTICYCLONES AND STORMS
L
Northern hemisphere:
The Coriolis force arises
deviation to the right
Within an anticyclone (H)
the winds turn clockwise
E
n
v
Within a storm (L) the
i
winds turn anticlockwise r
o
n
Southern hemisphere: m
The Coriolis force
e
arises deviation to the n
t
left
a
Within an anticyclone
l
H
H
(H) the winds turn
anticlockwise
L
Within a storm (L) the
winds turn clockwise
36
P
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ATMOSPHERIC GENERAL FLOW
1 Polar cell
2 Ferrell cell
3 Hadley cell
Simple model
Intertropical convergence zone
E
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t
a
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Air going down on the poles
(cold areas) and air ascending
on the equator (warm areas)
THIS SIMPLE MODEL
HAVEN’T IN MIND THE
EARTH’S ROTATION
http://www.newmediastudio.org/DataDiscovery/Hurr_ED_Center/Easterly_Waves/Trade_Winds/Trade_Winds.html
37
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ATMOSPHERIC GENERAL FLOW (CONTINUED)
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a
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WESTERN WINDS NEAR POLAR ZONES
Polar Arctic Circle
Polar Antarctic Circle
E
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o
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m
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t
a
l
ARCTIC
ANTARCTIC
Relationship with the ozone hole over Antarctica
39
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PLANETARY BOUNDARY LAYER
Transport phenomena within
PBL are related with turbulence
Troposphere
The planetary boundary layer (PBL) is the atmospheric region, nearest the Earth
surface (300-3000 m thickness), where it occurs the most of exchanges of energy
40
and matter. It is the zone where the interaction surface-atmosphere occurs.
E
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PLANETARY BOUNDARY LAYER (CONTINUED)
Turbulence: whirlpools arising
from several causes
10
1
SURFACE ROUGHNESS
SURFACE LAYER
100
TROPOSPHERE
EXTERN
LAYER
BASE OF THE CLOUDS
ROUGHNESS LAYER
Height (magnitude order, m)
1000
LIMIT LAYER (PBL)
TROPOPAUSE
10000
The planetary boundary
layer is the part of the
troposhpere directly
influenced by the Earth
surface. It is able to
answer to the stimulation
by surface forces wihin a
temporal scale of 1 hour or
less.
The forces associated with
the Earth’s surface include
drag friction, heat transfer,
evaporation and
transpiration, contaminant
releasing and ground
features able to modify the
air flux.
41
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DAILY VARIATION OF THE PBL
Sunrise
Surface
warming
PBL stirring
PBL increasing
thickness
Puesta
de Sol
Typical values at the end of
the evening 1 km (0.2 km 5 km)
1 km (0.2 km-5 km)
Sunset
Night
begins
Surface
cooling
Turbulence
drops or
disappears
100 m (20 m - 500 m)
PBL
thickness
dropping
Typical values 100 m
(20 m - 500 m)
Wind, temperature and other properties of
the PBL undergo fewer daily variations
over vast water surfaces as oceans and
great lakes than those over lands. This is
because the greater specific heat of water.
42
E
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TEMPERATURE DAILY CYCLE
Height
10.0 m
05:00
08:00
10:00
12:00
15:00
18:00
2.40 m
1.20 m
60 cm
30 cm
15 cm
-2 cm
-5 cm
-15 cm
T (ºC)
30
35
40
45
Typical summer profiles (land)
(data: July and August mean, based on A. H. Strahler, Geografía Física)
50
43
WATER CYCLE
Precipitation
13·1012 m3
99·1012 m3/ year
Oceans
423·1012 m3/ year
1350·1015 m3
Land
62·1012 m3/ year
33.6·1015 m3
Based on
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hyd/bdgt.rxml
F
í
s
i
c
a
A
m
b
i
e
n
t
a
l
37·1012 m3/ year
324·1012 m3/ year
99·1012 m3/ year
Evaporation &
transpiration
Undergraound
and surface
water
324·1012 m3/ year
m3/year
Atmosphere
Precipitation
423·1012
361·1012 m3/ year
361·1012 m3/year
62·1012 m3/year
Evaporation
ATMOSPHERIC BUDGET
44
S. Pal Arya, Introduction to Micrometeorology, 2th Edition. University Press.
Roland B. Stull, An Introduction to Boundary Layer Meteorology, Kluwer Academic Publishers
Coriolis acceleration
http://zebu.uoregon.edu/~js/glossary/coriolis_effect.html
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/crls.rxml
Anticyclons
http://vppx134.vp.ehu.es/met/html/diccio/anticicl.htm
Storms
http://vppx134.vp.ehu.es/met/html/diccio/borrasca.htm
http://www.rc-soar.com/tech/thermals.htm
http://f4bscale.worldonline.co.uk/Thermals.htm
45