8

Layers of the Atmosphere

A. Characteristics - lowest layer of the atmosphere - about 8-16 km up - has cooler temperatures in the upper regions than the lower regions - most dense layer of the atmosphere, contains up to 75% of its mass - consists of 78% nitrogen, 21% oxygen, and 1% trace gases - region where most weather occurs, such as clouds and thunderstorms - contains the tropopause, a region of stable temperature. This is where the troposphere ends and separates it from the stratosphere. A. Characteristics - second layer of the atmosphere, above the tropsophere - about 12-50km up - contains the ozone layer, which absorbs harmful ultraviolet radiation. This causes the rise of temperature until 0˚C. - generally free of weather or clouds - favorable for long-haul flights, which take place above turbulence and storms - the stratopause separates it from the mesosphere. The stratopause contains the highest temperature in the stratosphere. Characteristics - third layer of the atmosphere, above the stratosphere - about 50-80km up - temperatures drop with increasing altitude up to -100˚C. It is the coldest layer of the atmosphere. - sometimes has noctilucent clouds, which are formed by water vapor freezing into ice clouds. - also the region where meteors entering the atmosphere burn up, leaving a long, bright trail known as shooting stars. - separated from the thermosphere by the mesopause. This is the coldest region of the mesosphere Characteristics - largest but least moist layer of the atmosphere - about 80km and beyond - temperatures rise well over 1000˚C due to solar radiation, although the scarcity of air molecules means that it still feels very cold to humans. - the lower region of the thermosphere is the ionosphere (80-600km). This is where solar energy (ultraviolet and cosmic rays) ionizes the air molecules, leaving ions and electrons. This is also where aurorae occur. - the upper region of the thermosphere is the exosphere (600-10000km). This is the final part of the atmosphere where the air molecules are escaping due to its very low density. This is also where the atmosphere transitions into space, and thus, is where most low-level satellites orbit. A. "holes" in the ozone layer -mainly caused by cfc -if 1% of the ozone layer is depleted, 2% more UV-B rays can reach earth -can increase rate of diseases like malaria and cataract -1 possible solution is to find a good substitute for cfc B. global warming -increase in earth's temperature -possible effects:change in rainfall patterns, rising sea level C. climate change -is the change in weather patterns D. air pollution -caused by some human activities -any substance that goes to the atmosphere and damages living things or environment pollutes air E. enhanced greenhouse effect -we have been releasing more greenhouse gases since the industrial revolution -caused by some human activities
 * I. Troposphere**
 * II. Stratosphere**
 * III. Mesosphere**
 * IV. Thermosphere**
 * V. Some Issues reagarding Atmosphere**