earth is being cover with the blanket of gases called atmosphere which is further divided into 4 layers troposphere, stratosphere, mesosphere and thermospere each layer is made up of some chemical constituents which could be water molecule traces of gases etc, Japan has done research and send a satellite in space to observe it as describe in this presentation

1. STUDYING VERTICAL PROFILE OF ATMOSPHERE
BACKGROUND SUMMARY:
The Earth is surrounded by a blanket of air, which we call the atmosphere. It can
reach beyond 700 kilometers (435 miles) from the surface of the Earth, but we are only able
to see what occurs fairly close to the ground. Almost all of the Earth’s weather occurs in the
layer closest to the ground. Life on Earth is supported by the atmosphere, solar energy and
our planet's magnetic fields. The atmosphere absorbs the energy from the Sun, recycles
water and other chemicals, and provides a moderate climate. The atmosphere also works
with the electrical and magnetic forces to protect us from high-energy radiation and the
frigid vacuum of space.
The envelope of gas surrounding the Earth changes from the ground up. Four distinct
layers have been identified using thermal characteristics (temperature changes), chemical
composition, movement, and density. The layers from the ground up are: troposphere,
stratosphere, mesosphere, and thermosphere. The upper limit of the thermosphere is
referred to as the exosphere. This is where the Earth’s atmosphere blends into space. The
altitudes of the atmospheric layers are not constant. They vary depending on the season and
location on Earth, so other images showing the layers of the atmosphere may have different
heights. The image displayed on the Vertical Profile of the Atmosphere Graph with Pictures
predominantly uses the maximum height the layers can reach.
LAYERS OF ATMOSPHERE:
TROPOSPHERE:
 The lowest layer of Earth's atmosphere
 Extends from Earth's surface up to 7 km at the poles, and about 17-18 km at the
equator
 Objects Flying in this Layer: Airplanes
 Features: Most weather happens at this level - Clouds, rain, hurricanes
STRATOSPHERE:
 The second lowest layer of Earth's
atmosphere
 Extends from the top of the
troposphere. to about 50 km
 Objects Flying in this Layer: Weather
Balloons
 Features: Ozone Layer
MESOSPERE:
 The third highest layer in our
atmosphere, above the stratosphere
and below the thermosphere
 Extends from the top of the
stratosphere to the range of 80 to 85
km
 Features: Occasional meteors

2. THERMOSPERE:
 Outer layer of the atmosphere
 Extends from the top of the mesosphere to over 640 km
 The lower part of the thermosphere, from 80 to 550 km above the Earth's surface,
contains the ionosphere
 Objects Orbiting in the Layer: Space Shuttle & International Space Station
 Features: Aurora
EXOSPHERE:
 The highest layer of the atmosphere
 This layer often considered an extension of the thermosphere
 Extends from the top of the thermosphere up to 10,000 km
 The atmosphere here merges into space
 Objects Orbiting in this Layer: Satellites

3. STUDYING VERTICAL PROFILE OF ATMOSPHERE BY SATELITE:
The conventional method for measuring the vertical profiles of the atmosphere is by the
using the upper-air sounding system which regularly releases a weather balloon carrying a
radiosonde 4 times every day (figure 1). Recently, meteorological centers have started using
wind profilers and radiometers (figure 2) to enhance the upper-air observations. Such
measurements are usually carried out in a sparse upper-air observation network due to high
operating cost. To enhance the spatial coverage, polar orbiting meteorological satellites are
now used to measure the vertical profiles of the atmosphere.
Figure 1 AutomaticUpper-airSounding Figure 2 A windprofiler(left) andaradiometer(right)
Systemcarryinga radiosonde
How do polar-orbiting meteorological satellites measure the vertical profiles of the
atmosphere?
Some of the polar orbiting meteorological satellites, such as METOP and Feng-Yun 3, are
equipped with instruments (such as IASI, AMSU-A and IRAS) for measuring the vertical
profiles of the atmosphere. The vertical profiles that they can measure include temperature,
moisture content, as well as concentration of trace gases. These instruments, including
infrared sounders and microwave sounders, perform such measurements by remote sensing.
How to measure the moisture content of the atmosphere by remote sensing?
Various gaseous molecules in the
atmosphere absorb electromagnetic
waves at particular frequencies.
Figure 3 shows the absorption
spectrum of water vapors. Kirchhoff's
law of thermal radiation states that
the better an object is in absorbing
electromagneticwave at a particular
frequency; the more efficient it is in
emitting electromagnetic wave at

4. that frequency thermally. Hence, the atmosphere also emits electromagnetic wave. By
measuring the amount of electromagnetic wave emitted by the atmosphere with polar-
orbiting meteorological satellites, the vertical profiles can thereby be calculated.
How to measure temperature using infrared sounders?
The hotter an object is, the more intense electromagneticwave will be emitted. This is
Stefan-Boltzmann law. One example is the incandescent light bulb. The bulb will be brighter
when it is hotter.
How to measure the height of water vapors in the atmosphere?
The vertical profile of the atmosphere can be obtained by taking measurements of the
intensity of electromagnetic wave emittedby the atmosphere at multiple frequencies, as
different frequencies can indicate the condition of the atmosphere at different heights. For
example, if the measurement is taken at a frequency which is strongly absorbed by the
atmosphere, the electromagnetic wave measured by the satellite will be mainly emitted from
the top of the atmosphere. This is because the electromagnetic waveemitted near to the
Earth's surface would be absorbed by the upper part of the atmosphere and ultimately
cannot reach the satellite. On the other hand, if the measurement is taken at a frequency
which is weakly absorbed by the atmosphere, satellite will then mainly measure the
electromagneticwave emittednear the Earth's surface. This is because the density of air in
the lower part of the atmosphere is much higher than that in the upper part of the
atmosphere. Electromagnetic waveemitted near the Earth's surface still dominates in
intensity even though it is partially absorbedby the upper part of the atmosphere. By
measuring various frequencies, the satellite is able to "focus" on different heights of the
atmosphere. The vertical profile is then the result of integrating pieces of information
obtained at different heights.