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The atmosphere
-
Climate variations
Pär Holmgren
[email protected]
www.parholmgren.se
Dept. of Earth Sciences
Meteorology
”The knowledge about what is in the air.”
The physics and chemistry of the atmosphere.
The atmosphere
Radiation budget
General circulation
Greenhouse effect
Weather vs climate
What’s the difference?
What is weather?
What is climate?
Climate
Mark Twain: Climate is what we expect, weather is what we get.
The Blue Planet
Water is a unique in our solar system
•  71 percent of the
Earth is covered by
water and only 29
percent is landmass.#
Earth's atmosphere#
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Nitrogen 78.081%
Oxygen 20.945%
Argon 0.934%
Carbon dioxide 0.039%
Water vapor >1%
Other 0.002%
Atmosphere
•  No definite boundary between the
atmosphere and ”outer space”. It slowly
becomes thinner and fades into space. #
•  Three quarters of the atmosphere's mass is
within 11 km of the planetary surface. #
•  An altitude of 120 km marks a boundary
where atmospheric effects become noticeable
during re-entry of spacecrafts . #
Temperature and layers#
•  Troposphere: From the Greek word ”tropos” meaning to turn
or mix. The troposphere is the lowest layer of the atmosphere; it
begins at the surface and extends to between 7 km at the poles
and 17 km at the equator, with some seasonal variation due to
weather factors. The troposphere contains approximately 75% of
the atmosphere's mass and 99% of its water vapor and aerosols.
•  This is where we find the ”weather”!!
Temperature and layers#
Stratosphere: From the Latin word "stratus"
meaning a spreading out. The stratosphere extends
from the troposphere to about 50 km. Temperature
increases with height.
The stratosphere contains the ozone layer, the part of
the Earth's atmosphere which contains relatively high
concentrations of ozone. The ozone layer is mainly
located in the lower portion of the stratosphere, from
approximately 15 to 35 km above Earth's surface,
though the thickness varies seasonally and
geographically.
Temperature and layers#
•  Exosphere: from 500 – 1000 km up to 10,000 km,
free-moving particles that may migrate into and out of
the magnetosphere or the solar wind.
•  Ionosphere: ionized by solar radiation and contains
auroras. It affects radio propagation to distant places
on the Earth. It is located within in the thermosphere.
•  Thermosphere: from 80 – 85 km to 640 km,
temperature increasing with height
•  Mesosphere: From Greek word “meso” meaning
middle. The mesosphere extends from about 50 km to
80 or 85 km. Temperature decreasing with height.
Troposphere - Convection#
•  The troposphere has a great deal of
vertical mixing due to solar heating
at the surface, or convection. This is
the main source for most of the
weather! The heating warms bubbles
of air, which makes them less dense
so they rise. When a bubble of warm
air rises the pressure upon it
decreases so it expands, and the
temperature decreases. As the
temperature decreases, water vapor
in the air may condense or solidify,
creating clouds and precipitation.
The condensation releases energy “latent heat” - that further uplifts the
air bubble.!
Radiation budget
•  It represents the balance between#
•  The incoming energy (short wave) from
the Sun and#
•  The outgoing thermal (longwave) and
reflected energy from the Earth. #
Sun - Energy source - Seasons
Perihelion: 147 098 074 km
Aphelion: 152 097 701 km