1. UNIT 2 - ATMOSPHERE

2. ATMOSPHERE = COMPOSITION THE ATMOSPHERE INSULATES THE EARTH’S SURFACE-- IT IS HELD CLOSE TO THE EARTH BY GRAVITY

3. The atmosphere’s four layers Atmospheric layers have different Temperatures Densities Composition

4. ATMOSPHERE LAYERS

5. TROPOSPHERE: *Nearest to Earth’s surface ( active area that contains the air we breathe) *extends to 18 km above surface ( 7 miles) *weather occurs here (has clouds) *densest layer ( makes up about 75% of atmosphere’s mass) *temperature decreases as altitude increases (to – 60 ° C) *thin layer compare to the others *lowest altitude has the warmest portion due to surface radiated heat *Tropopause is the buffer zone between the Troposphere and next layer

6. STRATOSPHERE *above the troposphere *11 – 50 km above surface (7 – 31 miles) * commercial air planes travel here *lower part cold (-57° C) and has strong winds as part of a circulation pattern *has a thin Ozone Layer----(18 – 30 km/10 – 19 mi)--- protects Earth from harmful UV radiation *temperature increases as altitude increases due to absorption of UV heat by Ozone layer *stratopause: the buffer zone between stratosphere and next layer

7. MESOSPHERE *middle layer *extending from 50 to 90 km (31 – 60 mi) *coldest layer with low air pressure *temperatures decrease with altitude (-101° C ) *meteors burn here (shooting stars)

8. THERMOSPHERE *at about 100 km and above *space shuttle orbits here *also known as IONOSPHERE *temperature can reach 2000 ° C *temperature increases with altitude due to gamma rays, x-rays, & UV radiation converting atoms into IONS (called IONIZATION) *this layer reflects radiowaves which allow for long distance radio communication *the accumulation of IONS produce red and green lights known as Aurora Borealis (northern lights) and Aurora Australis (southern lights) https://www.youtube.com/watch?v=eJV_wlCm6m

9. Atmospheric properties Atmospheric pressure = the force per unit area produced by a column of air Relative humidity = the ratio of water vapor air contains to the amount it could contain at a given temperature Temperature = varies with location and time Atmospheric pressure decreases with altitude

10. AIR PRESSURE: the atmosphere is pulled down by gravity *Most of the mass of the Earth’s atmosphere is within the lower 30 km. (gets denser at surface) *measured in (hPA) = inches of mercury https://www.youtube.com/watch?v=xJHJsA7bYGc Weather forecasters measure air pressure with a barometer. Barometers are used to measure the current air pressure at a particular location in "inches of mercury" or in "millibars" (mb). A measurement of 29.92 inches of mercury is equivalent to 1013.25 millibars.

11. Air masses have different pressures High-pressure system = air that descends because it is cool It spreads outward as it nears the ground Brings fair weather Low-pressure system = warm air rises and draws air inward toward the center of low pressure Rising air expands and cools It brings clouds and precipitation

12. WEATHER VS CLIMATE WEATHER: the state of the atmosphere at a particular place at a particular time *short term. * the physical properties of weather that are measured : (wind speed, wind direction, temperature, air pressure, humidity, precipitation) CLIMATE: the average weather conditions at a particular place over a long period of time ( over 30 years ) * EX. Phoenix climate is Hot and dry

13. Air masses produce weather Front = the boundary between air masses that differ in temperature, moisture, and density Warm front = boundary where warm, moist air replaces colder, drier air Cold front = where colder, drier air displaces warmer, moister air Warm fronts produce light rain Cold fronts produce thunderstorms

14. NOAA = National Oceanic & Atmosphere Administration METEOROLOGISTS = STUDY WEATHER AND CLIMATE WHY DO WE HAVE WEATHER???? Weather results from the uneven warming of the Earth by the Sun.

15. Solar energy heats the atmosphere Energy from the sun: Heats and moves air Creates seasons Influences weather and climate Solar radiation is highest near the equator The sun’s energy heats the atmosphere, drives air circulation, and helps determine weather, climate, and the seasons.

16. CLIMATE EVIDENCE: GLACIER GAS BUBBLES TREE RINGS DEEP ICE CORE SAMPLES https://www.youtube.com/ watch?v=Atp412HEHDY https://www.youtube.com/ watch?v=Atp412HEHDY

17. Solar energy creates seasons Because the Earth is tilted, each hemisphere tilts toward the sun for half the year resulting in seasons

19. SOLAR ENERGY TRANSFER:

20. Solar energy causes air to circulate Air near Earth’s surface is warm and moist Convective circulation = less dense, warmer air rises Creating vertical currents Rising air expands and cools Cool air descends and becomes denser Replacing rising warm air Convection influences weather and climate

21. LATITUDE: the distance from the equator measured in degrees North and South of equator *high latitudes *low latitudes EQUATOR = 0 degrees NOTE: The most important factor that determines climate is the distance from the Equator

22. AIR CIRCULATION *Air moves because of solar heating * solar energy warms the Earth *warm air rises, expands, becomes less dense, forms Low Pressure System *cold air condenses, becomes denser and sinks, forms High Pressure System *as cold air sinks, it compresses and warms up, gets pushed to Low Pressure *a vertical current form = CONVECTION CURRENTS

23. HIGH AND LOW PRESSURE * HIGH PRESSURE forms at the surface = fair weather * LOW PRESSURE at the surface = stormy weather https://www.youtube.com/watch?v=rjODDPznqNM https://www.you tube.com/watch ?v=GkE3F5AuW BQ ***Know how to read the basics of a Weather Map L H

24. RAINSHADOW EFFECT A dry area on a mountain side because the mountain blocks the movement of wet air.

25. Thermal (temperature) inversion Thermal inversion = a layer of cool air occurs beneath warm air Inversion layer = the band of air where temperature rises with altitude Denser, cooler air at the bottom of the layer resists mixing Inversions trap pollutants in cities surrounded by mountains Air temperature decreases as altitude increases - Warm air rises, causing vertical mixing

26. WINDS air moving as a result of uneven heating *when large mass of warm moist air rise, cool air flows along Earth’s surface ---This Horizontal Airflow creates WINDS ANEMOMETER FOR WIND SPEED ---- WIND VANE FOR WIND DIRECTION Wind flows from areas of high pressure to areas of low pressure.

27. CORIOLIS EFFECT https://www.youtube.com/watch?v=dt_XJp77-mk https://www.youtube.com/watch?v=i2mec3vgeaI https://www.youtube.com/watch?v=dt_XJp77-mk https://www.youtube.com/watch?v=i2mec3vgeaI Coriolis Effect= is the deflection of moving objects viewed from a turning frame of reference *Coriolis effect explains the directional prevailing winds of the Earth The Earth rotates faster at the Equator than it does at the poles. This is because the Earth is wider at the Equator. Coriolis effect causes an air motion deflection path because of the Earth’s rotation. https://www.youtube.com/watch?v=7DVL0 ugj1O4

28. PREVAILING WINDS *TRADE WINDS= belts of winds between the equator and 30° N and S latitudes. *blow from Northeast in N. Hemisphere *blow from Southeast in S. Hemisphere *WESTERLIES= belts of winds between 30° and 60° *blow from Southwest in N. Hemisphere *blow from Northwest in S. Hemisphere *EASTERLIES= belts of winds between 60° and poles. *blow from Northeast in North Pole *blow from Southeast in South Pole

29. HORSE LATITUDES AND DOLDRUMS HORSE LATITUDES= a belt of calm air and sea occurring in both the northern and southern hemispheres between the trade winds and the westerlies. (30° TO 35° N & S of equator) DOLDRUMS=“equatorial belt of calms”, area around the earth centered slightly north of the equator between the two belts of trade winds. (5°N TO 5° S )

30. CIRCULATION CELLS HADLEY CELLS: FERREL CELLS: mid-latitude cells POLAR CELLS: at pole regions Ferrel cell

31. JET STREAMS = high stream currents in upper troposphere https://www.youtube.com/watch?v=huweohIh_ Bw https://www.youtube.com/watch?v=huweohIh_ Bw Jet streams are long, narrow current of fast moving air found in the upper atmospheric levels. They are found between 10 to 14 km high in the troposphere. They blow from west to east at speeds of 240 km/h and can dip northward or southward depending on atmospheric conditions. Air temperature differences drive the jet stream.

32. OCEAN CURRENTS AFFECT THE ATMOSPHERE

33. https://www. youtube.com /watch?v=Uu GrBhK2c7U

34. Storms pose hazards Atmospheric conditions can produce dangerous storms Hurricanes = form when winds rush into areas of low pressure Warm, moist air over the topical oceans rises Typhoons (cyclones) = winds turn counterclockwise in the Northern Hemisphere Drawing up huge amounts of water vapor Which falls as heavy rains Tornadoes = form when warm air meets cold air Quickly rising warm air forms a powerful convective current (spinning funnel)

35. Hurricanes and tornadoes Understanding how the atmosphere works helps us to: Predict violent storms and protect people Comprehend how pollution affects climate, ecosystems, and human health

36. HURRICANES https://www.youtube.com/watch?v=5iN352idL ks https://www.youtube.com/watch?v=5iN352idL ks *Hurricanes begin over warm oceans where trade winds meet and warm up *Thunderstorms form and move in a circular motion which makes it pick up moisture and heat energy. *The eye (center) is where there is descending air and low pressure. *Wind circles around the eye counter clockwise in the N. Hemisphere– it will circle clockwise in the S. Hemisphere NOTE: Typhoons are hurricane over the Northwest Pacific Ocean

37. HURRICANE CATEGORIES https://www.youtube.com/watch?v=nIWz60X MliE https://www.youtube.com/watch?v=nIWz60X MliE

38. TORNADOES https://www.youtube.com/watch?v=7bHSS1I mFQI https://www.youtube.com/watch?v=7bHSS1I mFQI *Tornadoes form when speeding cold fronts smash into warm humid air forming a convection of temperature and winds *Winds in tornadoes can reach speeds of over 250 km/h *the center of the tornado has low pressure *Tornadoes are un-predicatable