![]() ![]() The mesosphere, 50 to 80 km above the Earth, has diminished ozone concentration and radiative cooling becomes relatively more important. The stratosphere is warmer than the upper troposphere, primarily because of a stratospheric ozone layer that absorbs solar ultraviolet energy. It is a region of intense interactions among radiative, dynamical, and chemical processes, in which horizontal mixing of gaseous components proceeds much more rapidly that vertical mixing. The stratosphere and stratopause stretch above the troposphere to a height of 50 km. The temperature above the tropopause increases slowly with height up to about 50 km. The tropopause marks the limit of the troposphere and the beginning of the stratosphere. Molecules of nitrogen and oxygen compose the bulk of the troposphere. ![]() This region, constantly in motion, is the most dense layer of the atmosphere and the region that essentially contains all of Earth's weather. The troposphere is the lowest layer of the Earth's atmosphere, extending to a height of 8-15 km, depending on latitude. Troposphere stems from the Greek word tropos, which means turning or mixing. ![]() The layers, troposphere, stratosphere, mesosphere, thermosphere, and the exosphere, vary around the globe and in response to seasonal changes. The atmosphere, composed mainly of nitrogen and oxygen with traces of carbon dioxide, water vapor, and other gases, acts as a buffer between Earth and the sun. The air surrounding the Earth, described as a series of shells or layers of different characteristics. The same remote glaciers that provide evidence of natural variability in acidic deposition show, in their more recently formed layers, the increased deposition caused by human activity during the past half century. The use of tall smokestacks to reduce local pollution has contributed to the spread of acid rain by releasing gases into regional atmospheric circulation. The problem of acid rain not only has increased with population and industrial growth, it has become more widespread. These sources, plus the transportation sector, are the major originators of increased nitrogen oxides. Industrial and energy-generating facilities that burn fossil fuels, primarily coal, are the principal sources of increased sulfur oxides. Since the industrial revolution, emissions of sulfur and nitrogen oxides to the atmosphere have increased. The gases may be carried hundreds of miles in the atmosphere before they are converted to acids and deposited. Principal human sources are industrial and power-generating plants and transportation vehicles. The effects of acidic deposits have been detected in glacial ice thousands of years old in remote parts of the globe. The principal natural phenomena that contribute acid-producing gases to the atmosphere are emissions from volcanoes and from biological processes that occur on the land, in wetlands, and in the oceans. Occasional pH readings of well below 2.4 (the acidity of vinegar) have been reported in industrialized areas. Other gases, primarily oxides of sulfur and nitrogen, are converted to strong acids (sulfuric and nitric acids).Īlthough rain is naturally slightly acidic because of carbon dioxide, natural emissions of sulfur and nitrogen oxides, and certain organic acids, human activities can make it much more acidic. Carbon dioxide dissolved in rain is converted to a weak acid (carbonic acid). Oxidants play a major role in several of these acid-forming processes. Then, teachers can use NASA lessons to teach their students about science, technology, engineering and math.Acids form when certain atmospheric gases (primarily carbon dioxide, sulfur dioxide, and nitrogen oxides) come in contact with water in the atmosphere or on the ground and are chemically converted to acidic substances. These new inventions can help make life on Earth better.ĭo you like science, math and learning new things? Would you like to be an adventurer? Would you like to plan future missions to other planets and outer space? People at NASA work hard to share news about NASA’s missions with teachers. People who do not work at NASA can use NASA ideas to make new inventions. NASA also shares what they learn with others. A new program will send humans to explore the Moon and, one day, Mars. NASA scientists study things in the solar system and even farther away. The satellites help scientists learn more about Earth. science and technology that has to do with airplanes or space. NASA was started on October 1, 1958, as a part of the United States government. NASA stands for National Aeronautics and Space Administration. ![]()
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