1 Our atmosphere Important mixture of gases that sustain life on Earth Important mixture of gases that sustain life on Earth 480km (300 miles) thick 480km (300 miles) thick Beyond the atmosphere is the EXOSPHERE Beyond the atmosphere is the EXOSPHERE Contains small quantities of hydrogen and helium Contains small quantities of hydrogen and helium

2 Major components of the troposphere

3 Major Atmospheric Components Nitrogen Nitrogen Originates mostly from volcanic sources Originates mostly from volcanic sources Without nitrogen there would be no life Without nitrogen there would be no life Oxygen Oxygen By-product of photosynthesis By-product of photosynthesis Concentration of oxygen varies with latitude Concentration of oxygen varies with latitude

4 Argon Argon Constitutes almost 1% of the atmosphere Constitutes almost 1% of the atmosphere Not necessary for life but it used for some economic purposes Not necessary for life but it used for some economic purposes Carbon dioxide Carbon dioxide By-product of life By-product of life Important for keeping atmosphere warm Important for keeping atmosphere warm increases in CO 2 can cause an increase in atmospheric temperature increases in CO 2 can cause an increase in atmospheric temperature Water vapor Water vapor Variable from near 0 – 4 % Variable from near 0 – 4 %

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6 The Atmospheric Profile

7 The Atmosphere The troposphere The stratosphere The mesophere The thermosphere

8 The Troposphere (weathersphere) Water vapor, clouds, pollution, and life occur within the troposphere 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 ~ 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 Top of troposphere known as the tropopause

9 Lapse Rates in the Troposphere As we go upwards in the troposphere, the temperature decreases As we go upwards in the troposphere, the temperature decreases 6.4°C/1km or 3.5°F/1000ft = AVERAGE 6.4°C/1km or 3.5°F/1000ft = AVERAGE This number is not that important This number is not that important Can vary considerably with varying weather conditions and locations Can vary considerably with varying weather conditions and locations

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11 The stratosphere Temperatures increase from -57°C at the base of the stratosphere to O°C at the top (50km above Earth’s surface) Temperatures increase from -57°C at the base of the stratosphere to O°C at the top (50km above Earth’s surface) Why? Why? Top of the stratosphere is called the Stratopause Top of the stratosphere is called the Stratopause

12 The mesophere 50 – 80 km above Earth’s surface 50 – 80 km above Earth’s surface Outer boundary known as the mesopause Outer boundary known as the mesopause Temperature drops from O°C to - 90°C at the mesopause Temperature drops from O°C to - 90°C at the mesopause Occasional coalescence of cosmic and meteoric dust form clouds Occasional coalescence of cosmic and meteoric dust form clouds

13 The thermosphere Upper surface known as the thermopause Upper surface known as the thermopause Temperatures increase to ~1200°C at the thermopause Temperatures increase to ~1200°C at the thermopause

14 Atmospheric function Two main zones Two main zones The ozonosphere The ozonosphere The ionosphere The ionosphere

15 Functions of the atmosphere

16 Ozonosphere and Ionosphere OZONOSPHERE OZONOSPHERE Contains a high level of ozone Contains a high level of ozone Efficiently absorbs UV wavelengths of energy Efficiently absorbs UV wavelengths of energy Ozone is being depleted due to human activity Ozone is being depleted due to human activity Recent rebound Recent rebound IONOSPHERE Efficiently absorbs cosmic, gamma, x-rays, and UV wavelengths of energy

17 All the Earth’s energy ultimately comes from the sun All the Earth’s energy ultimately comes from the sun Weather and climate are ultimately driven by Weather and climate are ultimately driven by The energy gain from the sun The energy gain from the sun The Earth’s position relative to the sun The Earth’s position relative to the sun Electromagnetic spectrum Electromagnetic spectrum Mr. ROY G BIV Mr. ROY G BIV

18 HOW TO REMEMBER THE ORDER OF VISIBLE LIGHT ROY G BIV RED RED ORANGE ORANGE YELLOW YELLOW GREEN GREEN BLUE BLUE INDIGO INDIGO VIOLET VIOLET

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21 Solar radiation and Earth’s re- radiation