23 1 Characteristics of the Atmosphere Meteorology the

23. 1 Characteristics of the Atmosphere Meteorology – the study of the characteristics of the atmosphere Weather - the state of the atmosphere at a particular place and time (heat, dryness, wind, rain, sunshine, etc. ) Climate - prevailing weather conditions in an area over a long period (Cold in the winter; California is getting dryer)

Composition of the Atmosphere Nitrogen – 78% Oxygen – 21% Argon CO 2 – 0. 9% – 0. 04% CO 2 data as of March 2013) Water Vapor. . . variable (New

Gas cycles Oxygen is a result of natural cycles, maintaining a chemical balance in our atmosphere. Plants release O 2 as a byproduct of photosynthesis. Plants and animals use O 2 for life processes. Nitrogen moves from the air, to soil, to living things, and back to the air. Nitrogen-fixing bacteria pull N 2 from the air and form nitrogen compounds that can be used by animals & plants.

Atmospheric Pressure Gravity pulls matter toward the Earth. A 1 cm 3 column of air from sea level to the top of the atmosphere has a mass of 1. 03 kg. The force of the air is 10. 1 N (1. 03 kg x 9. 80 m/s 2 = 10. 094 N) You can feel pressure changes in your ears when you change altitudes (mountains, airplanes)

Measuring Atmospheric Pressure Mercurial Barometer – the atmosphere presses on a liquid in a well at the base, pushing up the column of mercury. (1 atmosphere – 760 mm Hg or 101. 3 k. Pa Aneroid Barometer – Sealed container in which air has been removed. Increased pressure causes the sides to bend inward, less pressure, sides bulge out.

Layers of the Atmosphere Exosphere – up to 10, 000 km (6200 mi) Merges into space; very low density Thermosphere (meaning “heat sphere”) Up to and over 640 km (400 miles) __mesopause__ Mesosphere – up to 80 -85 km (50 -53 mi) __stratopause__ From top to bottom. . . Stratosphere – up to 50 km (32 mi) __tropopause__ Troposphere- up to 7 km (23, 000 ft) at the poles, and 17 -18 km (56, 000 ft) at equator http: //science. howstuffworks. com/environmental/29269 -100 -greatest-discoveries-earths-atmospheric-layers-video. htm

Atmosphere layer Characteristics Troposphere: • very thin layer • most weather occurs here • warm at lower altitudes, colder at the top • most dense at the surface • contains 75% of the mass of the atmosphere

Atmosphere layer Characteristics Stratosphere: • Tropopause to 50 km (32 mi) • no water vapor; no weather • contains the ozone layer • temperature rises with increasing altitude From – 67∘ to 32∘ F (19∘ to 0∘ C)

Atmosphere layer Characteristics Mesosphere: • Stratopause to 85 km (53 mi) • Temperatures drop to -100 C • Coldest layer • Water vapor freezes into ice clouds • Meteors burn up in this layer

Atmosphere layer Characteristics Thermosphere: • Mesopause to 640 km (400 mi) • Temperatures rise to 2000 C • Hottest layer • Solar energy absorbed, but feels very cold (few molecules) • ISS orbits here • Aurora borealis occurs here • Ionosphere = lower portion • Exosphere = outer edge http: //www. youtube. com/watch? v=3 Cer. Jb. Z-dm 0