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The State of the Atmosphere
1. Atmospheric mass and pressure
2. Temperature structure
3. Geopotential
4. Circulation
5. Water in the atmosphere
Atmospheric mass and pressure
• From the equation of continuity, after integration for a polar cap limited by
WallSVV
vdsdsncdvcdivdvt
.)(
In the long-term mean: 0Wall
dsv
Assuming that the atmosphere is a ideal gas (p=RT) in hydrostatic equilibrium
z
dzgzp )(
we haveRT
dzg
p
dp and by integrating: )exp()(
0
0 z
z
dzRT
gpzp
We can then rewrite the first equation as:
Wallsurfh
vdsdsptg
_
0
1(1)
The rapid decrease of density with height distinguishes the atmosphere from the ocean
Distribution of mass in terms of pressure
• If H_surf=2.56x1014 m2
• PNorth_h=983.6mb, PSouth_h=988.0mb, PGlobe=983.6mb• g=9.8 m/s2
Then
m_North_h=2.57x1018 kg
m_Souh_h=2.58x1018 kg
m_Globe=5.15x1018 kg
...Distribution of mass in terms of pressure
The interhemispherictransport
From Eq. (1) we can calculate the transport trough the equator:
0 0
/][][z
dzdzvv
If p=1mb/month
smRmbmonth
mbR
v
/002.021012
1
1
12
][
2
Global distribution of temperature
Vertical and meridional change
Temporalvariabilityof temperature
Geopotential heights
Mean circulation
• Correlation coefficient between northern hemisphere stratospheric geopotential at 50hPa and an index representing the tropospheric 500hPA NAO.
Hadley model
Hadley (1735) wanted to explain trade wind circulationComplements of E. Kant and J. DaltonFerel (1856): Coriolis force and Geostrophic windHelmholtz: the role of friction-deviation of wind includes turbulent viscosity for the first time
Actual vertical circulation
• Kinetic energy of the atmosphere
• K=KTE +KSE +KM
• K=0.5[u2m+v2
m]
• KTE=0.5[(u‘2+v‘2) m]
• KSE=0.5[u m *2+v m *2]
• KM=0.5([u m] 2 +[v m] 2)
Precipitation