Atmosphere [EARTH SCIENCE]

• The earth is surrounded by all kind of gases. This layer is called the earth's Atmosphere. Without this atmosphere life on earth isn't possible. It gives us air, water, heat, and protects us against harmful rays of the sun and against meteorites.
• Atmosphere

  This layer around the earth is a colorless, odorless, tasteless 'sea' of gases, water and fine dust. The atmosphere is made up of different layers with different qualities. It consists of 78 percent nitrogen, 21 percent oxygen, 0.93 percent argon, 0.03 percent carbon dioxide and 0.04 percent of other gases.
• The Troposphere is the layer where the weather happens. Above this layer is the Stratosphere and in between them is the Ozone layer, that absorbs the sun's harmful ultraviolet rays. Above the Stratosphere is the Mesosphere, the Thermosphere including the Ionosphere - and the Exosphere. The atmosphere measures about 500 miles (800km).
• Layers of the Atmosphere

  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
  • Ionosphere
  • Exosphere
• The Troposphere is the lowest layer of the atmosphere and measures about 7 miles(12 km). It contains over 75 percent of all the atmosphere's gases and vast quantities of water and dust. As the sun heats the ground, it keeps this thick mixture churning. The weather is caused by these churnings of the mass. The troposphere is normally warmest at ground level and cools higher up where it reaches its upper boundary (the tropopause). The tropopause varies in height. At the equator it is at 11.2 miles(8 km) high, at 50 N and 50 S, 5.6 miles(9 km) and at the poles 3.7 miles(6 km) high.
• The Stratosphere extends from the tropopause up to its boundary (the Stratopause), 31 miles(50 km) above the Earth's surface. In this layer there is 19 percent of the atmosphere's gases and it contains little water vapour. Compared to the troposphere it is calm in this layer. The movements of the gases are slow. Within the stratosphere is the ozone layer, a band of ozone gas, that absorbs harmful ultraviolet rays of the sun. The higher you get in the atmosphere, the warmer the air gets. The temperature rises from -76 F (-60 C) at the bottom to a maximum of about 5 F(10 C) at the stratopause.
• The mesosphere is the next layer above the stratopause and extends to its upper boundary (the Mesopause), at 50 miles(80 km) above the ground. The gases in the mesosphere are too thin to absorb much of the sun's heat. Although the air is still thick enough to slow down meteorites hurtling into the atmosphere. They burn up, leaving fiery trails in the night sky. The temperatures in the mesosphere drop to -184 F(-120 C) at the mesopause.
• The Thermosphere is the layer above the mesopause. The gases of the thermosphere are even thinner than those in the mesosphere, but they absorb ultraviolet light from the sun. Because of this, the temperatures rise to 3,600 oF (2,000 oC) at the top. This is at a height of 430 miles (700 km) of the earth's surface. In the thermosphere is a separate layer, the Ionosphere. This layer extends of 62 miles(100 km) to 190 miles(300 km) of the earth's surface.
• The ionosphere is part of the thermosphere. It is made of electrically charged gas particles (ionised). The particles get this electric charge by ultraviolet rays of the sun. The ionosphere has the important quality of bouncing radio signals, transmitted from the earth. That’s why places all over the world can be reached via radio.
• The Exosphere is the outermost layer of the atmosphere and extends from 430 miles (700 km) to 500 miles (800 km) above the ground. In this layer gases get thinner and thinner and drift off into space.
• The atmosphere is of vital importance for life on earth. Without atmosphere life would be impossible. It gives us air to breathe and protects us from meteorites and ultraviolet rays from the sun. The atmosphere absorbs so much heat that temperatures on earth are such that life is possible. The weather, that exists by constant circulation of water to water vapor, to rain to water. This cycle causes, together with the differences in temperature and circulation of air (wind), erosion of the earth's surface. By erosion the outside of the earth changes through the years.
• Air Movement

  Warm air is less dense than cold air. Thus, warm air rises above cold air making the pressure below lower. The horizontal movement of air from high pressure area to lower pressure area produces wind.
• Sea Breeze

  When spending a day at the beach, a noticeable drop in temperature may occur during the early afternoon as a cool breeze begins to blow off of the water. This wind is known as the "sea breeze", which occurs in response to differences in temperature between a body of water and neighboring land.
• Sea Breeze

  Sea-breeze circulations most often occur on warm sunny days during the spring and summer when the temperature of the land is normally higher than the temperature of the water. During the early morning hours,

  the land and the water start out at roughly the same temperature. On a calm morning, a given pressure surface will be at the same height above both the land and water.
• Sea Breeze

  A few hours later, the sun's energy begins to warm the land more rapidly than the water. By later in the day, the temperatures of the land increases while the temperature of the water remains relatively constant. This occurs because water, especially large bodies of water like a lake or ocean, are able to absorb more energy than land without warming.
• Sea Breeze

  It is important to remember that the air is not heated directly from above by the sun. In fact, most of the incoming solar energy actually passes right through the atmosphere. However, as the land absorbs this energy, heat is radiated back into the atmosphere (from the earth), warming the overlying air. Some of this heat is transported to higher levels in the atmosphere through convection.
• Sea Breeze

  On the other hand, since the temperature of the water remains relatively constant throughout the day, the air over the water is not heated from below (as over land), resulting in lower air temperatures over the water.
• Land Breeze

  On clear, calm evenings, temperature differences between a body of water and neighboring land produce a cool wind that blows offshore. This wind is called a "land breeze". Land breezes are strongest along the immediate coastline but weaken considerably further inland.
• Land Breeze

  Land-breeze circulations can occur at any time of year, but are most common during the fall and winter seasons when water temperatures are still fairly warm and nights are cool.

  On clear and calm evenings, the earth's surface cools by radiating (giving off) heat back into space, and this results in a cooling of the immediately overlying air. Since the air over land cools more rapidly than the air over water, a temperature difference is established, with cooler air present over land and relatively warmer air located over water.
• Air Pollution

  When large amount of dust, soot, bacteria, and other harmful gases get into the air, air is being polluted. Today, the main sources of air pollution in the Philippines are : 1) industry and 2) transportation.
• Major Air Pollutants

  • ozone
  • carbon monoxide
  • nitrogen dioxide
  • particulate matter
  • sulfur dioxide
  • lead
  • toxic air pollutants
  • stratospheric ozone depleters
  • greenhouse gases
• ozone

  A gas that can be found in two places. Near the ground (the troposphere), it is a major part of smog. Higher in the air (the stratosphere), it helps block radiation from the sun.
• carbon monoxide

  A gas that comes from the burning of fossil fuels, mostly in cars. It cannot be seen or smelled.
• Nitrogen dioxide

  A reddish-brown gas that comes from the burning of fossil fuels. It has a strong smell at high levels.
• Particulate matter

  Solid or liquid matter that is suspended in the air. To remain in the air, particles usually must be less than 0.1-mm wide and can be as small as 0.00005 mm.
• Sulfur dioxide

  A corrosive gas that cannot be seen or smelled at low levels but can have a “rotten egg” smell at high levels.
• Lead

  A blue-gray metal that is very toxic and is found in a number of forms and locations.
• toxic air pollutants

  A large number of chemicals that are known or suspected to cause cancer. Some important pollutants in this category include arsenic, asbestos, benzene, and dioxin.
• Stratospheric ozone depleters

  Chemicals that can destroy the ozone in the stratosphere. These chemicals include chlorofluorocarbons (CFCs), halons, and other compounds that include chlorine or bromine.
• Greenhouse gases

  Gases that stay in the air for a long time and warm up the planet by trapping sunlight. This is called the “greenhouse effect” because the gases act like the glass in a greenhouse. Some of the important greenhouse gases are carbon dioxide, methane, and nitrous oxide.