Natural Climate and Human Impacts
Winter Term 11/12
Dr. Christoph Beck
Institute for Geography
Physical Geography and Quantitative Methods
University of Augsburg
[email protected]
Some (more) fundamentals of climatology
Vertical layering
of the atmosphere
Troposphere
(Barry & Chorley, 2003)
Some (more) fundamentals of climatology
Coupling of stratospheric and tropospheric dynamics
e.g.
Quasi-Biennial-Oscillation (QBO)
(quasi-periodic
oscillation of the
equatorial zonal
wind between
easterlies and
westerlies in the
tropical stratosphere
with a mean period
of 28 to 29 months)
Monthly zonal mean wind in m/s against pressure in mb
at 1.25 ° north of the equator.
Easterlies are coloured yellow to blue and westerlies orange to
red
Structure and composition of the atmosphere
Composition
of the atmosphere
(Barry & Chorley, 2003)
Solar and terrestrial radiation – the global energy budget
Variations of solar radiation with latitude and season
(Barry & Chorley, 2003)
Solar and terrestrial radiation – the global energy budget
Long-term Variations of solar radiation
(Barry & Chorley, 2003)
Solar and terrestrial radiation – the global energy budget
Long-term Variations of solar radiation
(www.spaceweather.com)
Solar and terrestrial radiation – the global energy budget
Spectral distribution
of solar and
terrestrial radiation
solar
Total energy emitted
following Stefan‘s Law:
E=σ∗ε ∗T
F = σT4
4
Wavelength of maximum
emission
according to Wien‘s Law:
terrestrial
λ max∗T=const .
λ max = 2.897/ T x 10-6 m
(Barry & Chorley, 2003)
Solar and terrestrial radiation – the global energy budget
Reflection of short-wave radiation
by the atmosphere
http://www.geography.hunter.cuny.edu/~tbw/wc.notes/
1.atmosphere/notes1.htm
Solar and terrestrial radiation – the global energy budget
Modification of solar radiation in the atmosphere
Depending on wavelength:
- Absorption
(O2, O3, CO2, H2O)
- Scattering
(Aerosols, Cloud droplets)
- Reflection
(Clouds)
Global (total) solar radiation received at the earth’s surface (~ 50% of
extraterrestrial radiation), comprising direct (Q) and diffuse (q) solar Radiation
Fractions of Q and q depending on cloudiness, depth of atmosphere (< altitude of
the sun, ...)
Solar and terrestrial radiation – the global energy budget
Solar radiation at the earth's surface
(Barry & Chorley, 2003)
Mean annual global solar radiation (direct (Q) + diffuse (q))
Solar and terrestrial radiation – the global energy budget
Mean annual albedo
at the earth's surface
at the top of the atmosphere
(Barry & Chorley, 2003)
Solar and terrestrial radiation – the global energy budget
Changing land surface properties affecting reflectivity (albedo)
e.g. variations in snow coverage
Maximum snow cover in North America
during the same 8-day period in each of
four consecutive years (2001-04)
Derived from the Moderate Resolution
Imaging Spectroradiometer (MODIS),
flying aboard NASA’s Terra satellite
http://eobadmin.gsfc.nasa.gov/Newsroom/NewImages/images.php3?img_id=1645
Solar and terrestrial radiation – the global energy budget
Absorption of solar radiation
at the earth's surface
(Barry & Chorley, 2003)
Solar and terrestrial radiation – the global energy budget
The earth's global mean energy balance
(IPCC, 2001)
Solar and terrestrial radiation – the global energy budget
The earth's global mean energy balance
Net radiation at the earth's surface = Rn
Q:
direct solar radiation
q:
diffuse solar radiation
a:
Albedo
L u:
terrestrial IR-radiation
L d:
atmospheric back-radiation
global solar radiation (short-wave)
(long-wave)
Rn = (Q + q) * (1 - a) – Lu + Ld
Solar and terrestrial radiation – the global energy budget
The earth's global mean energy balance
Heat budget at the earth's surface
Rn + A = LE + H + St + Ph
Rn:
A:
H:
LE:
St:
Ph:
Net radiation
Anthropogenic heat flux
Sensible heat flux
Latent heat flux
Storage term
Photosynthesis
Solar and terrestrial radiation – the global energy budget
Net radiation at the earth's surface – spatial variations
(Barry & Chorley, 2003)
Annual net radiation at the earth's surface
Solar and terrestrial radiation – the global energy budget
Sensible and latent heat fluxes – spatial variations
(Barry & Chorley, 2003)
Global distribution of (vertical) sensible heat flux
Solar and terrestrial radiation – the global energy budget
Sensible and latent heat fluxes – spatial variations
(Barry & Chorley, 2003)
Global distribution of (vertical) latent heat flux
Solar and terrestrial radiation – the global energy budget
Large-scale (meridional) variations of the energy budget
Energy surplus in low-latitude regions
vs.
energy deficit in high-latitude regions
leading to
horizontal poleward heat transport
(Barry & Chorley, 2003)
Solar and terrestrial radiation – the global energy budget
Poleward energy transfer in the earth-atmosphere system
via
the atmospheric
and the
oceanic circulation
(Wilson et al., 2000)
Contributions to the poleward heat transport by the oceans and the
atmosphere in the Northern hemisphere
Solar and terrestrial radiation – the global energy budget
Poleward energy transfer in the earth-atmosphere system
via
the atmospheric
and the
oceanic circulation
including transfer of
sensible and latent heat
Average annual latitudinal distribution
of the components of the poleward
energy transfer (1015W) in the
earth-atmosphere system.
(Barry & Chorley, 2003)
Solar and terrestrial radiation – the global energy budget
Global temperature distribution
(Barry & Chorley, 2003)
Mean temperatures in January
Solar and terrestrial radiation – the global energy budget
Global temperature distribution
(Barry & Chorley, 2003)
Mean temperatures in July