1. Atmospheric Pressure and
Atmospheric Temperature
Andino Maseleno
Alif bin Haji Alias

2. Atmospheric Pressure
Atmospheric pressure is the force per unit area exerted on a surface
by the weight of air above that surface in the atmosphere of earth (or
that another planet).
In most circumstances atmospheric pressure is closely approximated
by the hydrostatic pressure caused by the weight of air above the
measurement point.
On a given plane, low-pressure areas have less atmospheric mass
above their location, whereas high-pressure areas have more
atmospheric mass above their location. Likewise, as elevation
increases, there is less overlying atmospheric mass, so that
atmospheric pressure decreases with increasing elevation.

3. The standard atmosphere (symbol: atm) is a unit
of pressure equal to 101325 Pa or 1013.25
milibars or hectopascals.

4. The pressure of an atmospheric gas decreases with altitude due to the
diminishing mass of gas above each location. The height at which the
pressure from an atmosphere declines by a factor of e (an irrational
number with a value of 2.71828..) is called the scale height and is
denoted by H.
For an atmosphere with a uniform temperature, the scale height is
proportional to the temperature and inversely proportional to the
mean molecular mass of dry air times the planet's gravitational force
per unit area of on the surface of the earth. For such a model
atmosphere, the pressure declines exponentially with increasing
altitude. However, atmospheres are not uniform in temperature, so
the exact determination of the atmospheric pressure at any particular
altitude is more complex.

5. • The mean sea level pressure (MSLP) is the atmospheric pressure at sea
level or (when measured at a given elevation on land) the station pressure
reduced to sea level assuming that the temperature falls at a lapse rate of
6.5 K per km in the fictive layer of air between the station and sea level.
• This is the atmospheric pressure normally given in weather reports on
radio, television, and newspapers or on the Internet. When barometers in
the home are set to match the local weather reports, they measure
pressure reduced to sea level, not the actual local atmospheric pressure.
• The reduction to sea level means that the normal range of fluctuations in
atmospheric pressure is the same for everyone. The pressures that are
considered high pressure or low pressure do not depend on geographical
location. This makes isobars on a weather map meaningful and useful
tools.

8. Atmospheric Temperature
Atmospheric temperature is a measure of
temperature at different levels of the Earth’s
atmosphere. It is governed by many factors,
including incoming solar radiation, humidity and
altitude.

9. In the Earth's atmosphere, temperature varies
greatly at different heights relative to the Earth’s
surface. The coldest temperatures lie near
the mesopause, an area approximately 85 km to
100 km above the surface. In contrast, some of
the warmest temperatures can be found in the
thermosphere, which receives strong ionizing
radiation.

11. References
http://en.wikipedia.org/wiki/Atmospheric_press
ure
http://en.wikipedia.org/wiki/Atmospheric_temp
erature