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Our atmosphere. Important mixture of gases that sustain life on Earth 480km (300 miles) thick Beyond the atmosphere is the EXOSPHERE Contains small quantities of hydrogen and helium. Major components of the troposphere. Major Atmospheric Components. Nitrogen
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Our atmosphere • Important mixture of gases that sustain life on Earth • 480km (300 miles) thick • Beyond the atmosphere is the EXOSPHERE • Contains small quantities of hydrogen and helium
Major Atmospheric Components • Nitrogen • Originates mostly from volcanic sources • Without nitrogen there would be no life • Oxygen • By-product of photosynthesis • Concentration of oxygen varies with latitude
Argon • Constitutes almost 1% of the atmosphere • Not necessary for life but it used for some economic purposes • Carbon dioxide • By-product of life • Important for keeping atmosphere warm • increases in CO2 can cause an increase in atmospheric temperature • Water vapor • Variable from near 0 – 4 %
The Atmosphere The thermosphere The mesophere The stratosphere The troposphere
The Troposphere (weathersphere) • Water vapor, clouds, pollution, and life occur within the troposphere • ~ 18km (11 miles) thick at equator; 12 km (8 miles) thick in the mid-latitudes; and 8km (5 miles) thick near the poles • Top of troposphere known as the tropopause
Lapse Rates in the Troposphere • As we go upwards in the troposphere, the temperature decreases • 6.4°C/1km or 3.5°F/1000ft = AVERAGE • This number is not that important • Can vary considerably with varying weather conditions and locations
The stratosphere • Temperatures increase from -57°C at the base of the stratosphere to O°C at the top (50km above Earth’s surface) • Why? • Top of the stratosphere is called the Stratopause
The mesophere • 50 – 80 km above Earth’s surface • Outer boundary known as the mesopause • Temperature drops from O°C to - 90°C at the mesopause • Occasional coalescence of cosmic and meteoric dust form clouds
The thermosphere • Upper surface known as the thermopause • Temperatures increase to ~1200°C at the thermopause
Atmospheric function • Two main zones • The ozonosphere • The ionosphere
OZONOSPHERE Contains a high level of ozone Efficiently absorbs UV wavelengths of energy Ozone is being depleted due to human activity Recent rebound IONOSPHERE Efficiently absorbs cosmic, gamma, x-rays, and UV wavelengths of energy Ozonosphere and Ionosphere
All the Earth’s energy ultimately comes from the sun • Weather and climate are ultimately driven by • The energy gain from the sun • The Earth’s position relative to the sun • Electromagnetic spectrum • Mr. ROY G BIV
HOW TO REMEMBER THE ORDER OF VISIBLE LIGHTROY G BIV • RED • ORANGE • YELLOW • GREEN • BLUE • INDIGO • VIOLET