Atmosphere

The initial step in the depletion of stratospheric ozone by human activities is the emission, at Earth's surface, of ozone-depleting gases containing chlorine and bromine. Most of these gases accumulate in the lower atmosphere because they are nonreactive and do not dissolve readily in rain or snow. Eventually, these emitted source gases are transported to the stratosphere, where they are converted to more reactive gases containing chlorine and bromine. These more reactive gases then participate in reactions that destroy ozone. Finally, when air returns to the lower atmosphere, these reactive chlorine and bromine gases are removed from Earth's atmosphere by rain and snow.

The amount of ozone in the atmosphere is measured by instruments on the ground and carried aloft on balloons, aircraft and satellites. Some measurements involve drawing air into an instrument that contains a system for detecting ozone. Other measurements are based on ozone's unique absorption of light in the atmosphere. In that case, sunlight or laser light is carefully measured after passing through a portion of the atmosphere containing ozone.

No, the total amount of ozone above the surface of Earth varies with location on time scales that range from daily to seasonal and longer. The variations are caused by stratospheric winds and the chemical production and destruction of ozone. Total ozone is generally lowest at the equator and highest near the poles because of the seasonal wind patterns in the stratosphere.

Ozone in the stratosphere absorbs some of the Sun's biologically harmful ultraviolet radiation. Because of this beneficial role, stratospheric ozone is considered good ozone. In contrast, excess ozone at Earth's surface that is formed from pollutants is considered bad ozone because it can be harmful to humans, plants and animals. The ozone that occurs naturally near the surface and in the lower atmosphere is also beneficial because ozone helps remove pollutants from the atmosphere.

There are three types of clouds:

☆ Cumuliform: Clouds formed by rising air in a convection.

☆ Stratiform: Clouds formed in layers from an inversion.

☆ Cirriform : Clouds made of ice crystals at high altitude.

Ozone is formed throughout the atmosphere in multistep chemical processes that require sunlight. In the stratosphere, the process begins with an oxygen molecule being broken apart by ultraviolet radiation from the Sun. In the lower atmosphere (troposphere), ozone is formed in a different set of chemical reactions involving hydrocarbons and nitrogen-containing gases.

Ozone is found primarily in two regions of the atmosphere. About 10% of atmospheric ozone is in the troposphere, the region closest to Earth (from the surface to about 10-16 kilometers (6-10 miles)). The remaining ozone (about 90%) resides in the stratosphere between the top of the troposphere and about 50 kilometers (31 miles) altitude.

The absolute humidity is the actual volume of water per volume of air. The relative humidity is how close to dew point a parcel of air is, for a given temperature.

The temperature at which a parcel of air can not contain more moisture without condensing. At that temperature, the relative humidity is 100 percent.

A large cumulus cloud formed from a strong convection of humid air. It causes rain and, sometimes, thunderstorms.

Because during fall and winter, the difference between tropical and polar air is much greater.

The separation between polar cold air and temperature mild air is called a polar front.

Jet streams are strong winds on the top of the troposphere that are caused by the sharp altitude change in the troposphere and the Coriolis force.

A cold front, being steeper, moves faster than a warm one and when they merge, they form what is called an occlusion front.

A thunderstorm can happen in any condition, snow and even fog but it happens mostly during the summer when the sun is high and warms the surface.

Air masses with a great difference of temperature between the surface and the troposphere.

Hail is rain that is taken upward by a very strong convection and it freezes before it falls back to the surface of the earth.

1013 hPa or 29.9 Mg In.

When the air rises, either because warmer or because of the terrain is called a convection.

When the air is warmer aloft than on the surface is called an inversion.