Domains of Earth: Atmosphere

Atmosphere

An atmosphere is a layer of gases that envelop a planet.

Our atmosphere is special because composition is capable of supporting life, with

oxygen being important for living organisms. Our atmosphere is also important in
maintaining temperature, trapping heat during nighttime and absorbing adequate heat
during daytime. All weather phenomena also occur within the atmosphere because of
the presence of air and water vapor.

Composition

78% nitrogen
21% oxygen
1% trace gases (carbon dioxide, argon, other inert gases, etc.)

Layers of the Atmosphere

Troposphere (~12 km)

 The lowest layer and the layer where we live in.

 Makes up 75% of the atmosphere’s mass and 99% of the atmosphere’s water.
 Air is turbulent which is caused by the interaction between the cold and warm
air.
 Clouds formation is present in this layer because 99% of water vapor is in the
troposphere.
 The air pressure and temperature drop the higher the altitude as cold as -51°C
 Long wavelength rays such as infrared and radio waves are able to reach this
layer.
 Light reaches this layer as well.

Stratosphere (12 km – 50 km)

 Second lowest layer

 Ozone Layer is located on this layer. This thin layer of gas (around 3mm) is
capable of shielding harmful ultraviolet (UV) rays that are harmful to humans by
damaging cells and causing cancer. The absorbed UV rays is then converted into
heat, making the stratosphere significantly hotter despite having higher altitude
at most around -15°C.
 Air is less turbulent in this layer, making most aircraft fly between the boundaries
of troposphere and stratosphere.

Mesosphere (80 km – 700 km)

 Third layer
 The coldest layer of the atmosphere, reaching as low as -90°C.
  Meteors burn up because of friction because of air resistance.
 The scarcity of water vapor leads to the formation of noctilucent clouds, tenuous
cloud-like phenomena in the upper atmosphere of Earth as a result of diffusion of
water ice crystals in the mesosphere.

Noctilucent clouds are most often observed during the summer months from latitudes between ±50° and ±70°

Thermosphere (80 km – 700 km)

 Second uppermost layer

 Absorbs significant amount of UV radiation, gamma and X-rays and converting it
to ions, forming the Ionosphere.
 Solar activity influences the temperature of the thermosphere, making this layer
reach temperatures ranging between 500°C to more than 2500°C.
 The Ionosphere is the ionized part of the upper atmosphere. This layer reflects
and absorbs radio waves allowing us to receive shorter wave radio broadcasts
from other parts of the world.
 In the ionosphere, the ions of the solar wind collide with atoms of oxygen and
nitrogen from Earth’s atmosphere. The energy released during these collisions
causes a colorful glowing halo around the poles, this is called an aurora.

Auroras are visible almost every night near the Arctic and Antarctic Circles, which are about 66.5 degrees north and south

Exosphere (700 km – 10000 km)

 Uppermost layer
 A layer that IS located in the area already considered as the outer space.
  Extremely low densities of hydrogen, helium, and other molecules, making it
possible for them to travel large distances without colliding.
 Because of the low density of molecules, this layer does not behave like gas that
traps molecules and therefore most particles in this layer escape into space.
 Because of its low density, there is minimal friction, making this layer best for
launching satellites.

Natural Processes

Cloud Formation and Rain

Following the water cycle, water evaporates because of the heat emitted by the
sun, turning into water vapor which moves upward. The decreasing temperature of the
atmosphere as the altitude increases causes the water vapor to condense into water
droplets, accumulating to form clouds. Once a cloud is heavy enough that it could not
hold enough water droplets to suspend in the sky, they fall back to earth as rain.

Greenhouse Effect

The greenhouse effect is a natural phenomenon the makes the Earth warmer
with the help of our atmosphere. This played a crucial role in developing life on this
planet.

Notorious gases such as carbon dioxide, methane and ozone that constitute the
atmosphere are considered as greenhouse gases, capable of trapping heat emitted by
the sun and reflecting it back to the surface. This process makes the surface of the Earth
warmer. However, the abundance of these greenhouse gases as the result of human
activity leads to more heat being trapped, making the Earth absorb too much heat and
causing global warming.

Typhoon

Typhoons/Hurricanes/Cyclone are clouds and thunderstorms originating from

tropical ocean waters, forming a cloud circulation.

Typhoons are usually formed by warm ocean waters interacting with cold, more
unstable air. The warm humid air caused by evaporation rises over the water, into the
atmosphere. The warm air then condenses into a cloud, forming a low-pressure area
below it. Cold air from high pressure areas converge to the low-pressure area, warming
the air and starts rising as well. As long as cold air continue to interact with the low-
pressure area, a typhoon will continue to grow as well.

Parts

The eye is the center of the typhoon, characterized by relatively calm and clear
weather. It is a circular region of light winds and descending air, often with a
clear sky.

Surrounding the eye is the eyewall, which is the most intense part of the typhoon.
It consists of a ring of towering thunderstorms where the strongest winds and
heaviest rainfall occur.

Rainbands are bands of clouds and precipitation that spiral outward from the
center of the typhoon. They are responsible for the widespread and often heavy
rainfall associated with the storm. These bands can extend over a wide area,
causing significant amounts of rainfall and contributing to the overall impact of
the typhoon.

Coriolis Effect

The Coriolis effect is a phenomenon that describes the apparent deflection of

moving objects, such as air or water currents, on the surface of the Earth due to the
Earth's rotation. It causes water and air to curve as they travel across the Earth’s surface.
This the reason reason why typhoon spins.
 Our Earth rotates from west to east. Because of the shape of the Earth, the
equator spins faster than the polar areas. This means that southern winds are pulled
westward, while northern winds are pulled to the east. This is also the reason why
Northeast (amihan) and Southwest (habagat) monsoons are named as such. Through
Coriolis effect, typhoons moving north are spinning clockwise and typhoons moving
south move counterclockwise.

The easterlies are global wind patterns that blow from the east to the west. They
are predominant near the Earth's equator and in the polar regions. The tropical
easterlies refer to the trade winds that blow from the northeast in the Northern
Hemisphere and from the southeast in the Southern Hemisphere. These winds are a
result of the Coriolis effect and the temperature difference between the equator and the
poles.

The westerlies are prevailing winds that blow from the west to the east in the
middle latitudes between 30 and 60 degrees both in the Northern and Southern
Hemispheres. These winds are responsible for the movement of weather systems from
west to east in the mid-latitudes, affecting the climate of regions within their influence.

Philippines and Pacific Ocean

Because Philippines is situated in the Pacific, it is considered as one of the

typhoon hotspots of the world, being more prone to typhoons than landlocked
countries.

PAGASA, a meteorological institute in the Philippines uses a warning scale to

denote the severity of a typhoon. Classified as signals and categorized on their wind
speed. Initially a four-point system, PAGASA introduced a fifth signal for powerful
supertyphoons such as Typhoon Haiyan (Yolanda) reaching maximum sustained winds
of 230km/h making it one of the strongest cyclones ever recorded.
 Greenpeace said that based on the new definition issued by PAGASA, the
Philippines experienced 7.5 times more super typhoons from 2016-2021 than
previously recorded. PAGASA changed the classification of supertyphoons from cyclones
that exhibit maximum sustained winds of at least 220 kilometers per hour to 185
kilometers per hour. Based on the old definition, the Philippines encountered only 2
supertyphoons from 2016 to 2021. With the new definition, 14 of the 39 typhoons that
passed the country in the last six years can be classified as super typhoons.