Atmosphere L AY E RS O F T H E AT MOSPHERE

Transcription

1 Atmosphere L AY E RS O F T H E AT MOSPHERE

2 Why is the atmosphere divided into 5 different layers? The atmosphere is divided into five different layers because the atmosphere is not uniform, its properties change with altitude. Two properties change with altitude, the AIR PRESSURE and the AIR TEMPERATURE Lets look at each layer individually.

3 The earth is surrounded by a blanket of air that we call atmosphere. The atmosphere is considered in terms of layers, or regions, arranged like spherical shells above the surface of the Earth. ATMOSPHERE

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5 The atmosphere is primarily composed of nitrogen (N2, 78%), oxygen (O2, 21%), and argon (Ar, 1%). A myriad of other very influential components are also present which include the "greenhouse" gases or ozone (0-0.01%), carbon dioxide (CO2, 0.033%). COMPOSITION OF THE ATMOSPHERE

6 There are 4 layers in the atmosphere They are the troposphere, mesosphere, thermosphere, and stratosphere LAYERS OF THE ATMOSPHERE

7 TROPOSPHERE This is the layer that is closest to the surface of the earth It s elevation ranges from 0 to 10 km This is where all plants and animals live and breathe Where weather takes place Air is mixes Temperature decreases with altitude

8 Pale blue gas with a strong odor. 90% of all ozone is found in the stratosphere 10% is found in the troposphere Ozone is extremely important because it is the only gas that absorbs ultraviolet radiation from the Sun and protects the surface of the Earth and people from the damaging effects of UV rays Ozone Layer

9 This layer sits on top of the troposphere It s elevation ranges from 10 km to around 25 km This layer contains the ozone layer, which protects us from harmful sunlight People can not breathe in this layer. Stratosphere

10 This layer is above the stratosphere. It s elevation ranges from 25 to 100 km Temperature decreases with altitude This is where we see "falling stars" meteors burning up as they fall to Earth The mesosphere is the coldest layer of the atmosphere. Radio waves are reflected back to earth in the mesosphere. MESOSPHERE

11 An extension or a part of the thermosphere. So technically, the ionosphere is not another atmospheric layer. Free electrons and ions tend to recombine Ionosphere

12 This is the highest layer of the atmosphere It s height ranges from 100 to 400 km This is where most small meteorites burn up and is also the location in the atmosphere that the northern lights occur (aurora borealis) Layer of the atmosphere which is first exposed to the Sun's radiation and so is first heated by the Sun. The air is very thin The temperature dependent on solar activity. THERMOSPHERE

13 Highest layer of the atmosphere. The air is very thin here Atoms and molecules escape into space Exosphere

14 Label the layers of the atmosphere below: 1.TROPOSPHEREcontains dust, moisture, weather. 2.STRATOSPHERE - contains protective ozone 3. MESOSPHERE- coldest layer 4. THERMOSPHEREcontains auroras, high temperature but low heat 5. EXOSPHERE- The highest layer of the atmosphere where commercial satellites are located.

15 Weather & Climate

16 Weather & Climate Definitions Weather- the state of the atmosphere with respect to heat or cold, wetness or dryness, calm or storm, clearness or cloudiness. Climate the average course or condition of the weather at a place usually over a period of years as exhibited by temperature, wind velocity, and precipitation

17 What causes Weather? All elements of weather are the direct result of energy from the sun. The sun s rays hit earth and the land absorbs the heat unevenly. This uneven heating causes changes in weather.

18 What does weather include? Air temperature Cloud cover Amount of sunlight Relative humidity Precipitation Wind speed Wind direction

19 Temperature Temperature is amount of heat in a substance. Expressed in degrees Fahrenheit or Centigrade (Celsius) Temperature is measure by an instrument called a thermometer.

20 A Bunch of Hot Air. Cold air contracts or sinks. The air molecules get closer together, which makes the air heavier or more dense. Hot air expands or rises. The molecules get further apart, become less dense and they get lighter.

21 Air Circulation Since warm air rises, the upper part of the room is the warmest. The coolest part of the room would be closer to the floor.

22 Wind Spiral Why is the spiral able to turn? The hot air rising is turning the spiral.

23 Wind Wind is moving air in the atmosphere. Air is always moving from high pressure to low pressure. The strongest winds are tornadoes, the air pressure is extremely low.

24 How to measure wind speed Wind speed is measure in kilometres per hour (kph). We use a device called an anemometer. Wind Direction is always stated in terms of where the wind is coming from.

25 Measuring Wind Direction Wind Sock Weathervane

26 Humidity- Moisture in the Air The sun heats up the water on land and causes evaporation. The moisture that is in the air is called humidity. Saturated is when the air has too much moisture and cannot hold anymore.

27 The Water Cycle The sun heats up the water- evaporation The water vapor (gas) condenses into clouds The clouds become saturated and precipitation is the result. The precipitation pools in lakes, oceans and rivers. Waiting to evaporate again.

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29 Relative Humidity It is the ratio of how much moisture is in the air and how much the air can hold. 50% humidity means the air is holding 50% moisture

30 Precipitation When there is too much moisture, the water will fall as precipitation. Precipitation will fall in two main forms: rain or snow depending on the temperature of the air through which the moisture will fall. Other forms of precipitation are sleet and hail.

31 Forms of Precipitation

32 Snow If the air is cooled below the freezing point of water, the condensing moisture is quickly freeze into ice crystals. The ice crystals join to make snowflakes Snowflakes are always six sided.

33 When droplets of moisture join together becoming heavy enough to fall to the ground. Rain

34 Hail Formed in cumulonimbus (storm) clouds. They are frozen droplets of moisture.

35 When falling rain starts off in warmer air, but passes through air below freezing, the rain drops cool and freeze onto surfaces when they hit the ground. Sleet

36 Facts on Precipitation It takes 10 centimetres of snow to make one centimetre of rain. Dew is moisture in the air cools off at night. In the morning it is found on everything. In colder temperatures, dew is frost.

37 Air Pressure The force that is applied on everything on the Earth caused by the weight of the air. Air particles are mobile, the exert pressure on objects. High air pressure brings warm, dry air. Low air pressure brings rain or moisture Air pressure can change quickly, ie- when a storm comes in. There are three factors that affect air pressure: altitude, air mass temperature and the amount of moisture in the air. A Barometer is used to measure air pressure.

38 Clouds Clouds come in many shapes and forms. Some are high in the sky, while others are so low they touch the ground. No matter what shape or elevation, clouds form the same way, by having water vapor condense onto small solid particles like dust, sea salt, and pollution

39 Clouds Clouds serve several important functions. They provide rain and snow. They also help retain heat, so it doesn t escape quickly back into space. On hot days, clouds provide shade

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41 Can you identify these clouds?

42 Seasons The Earth orbits around the sun. The Earth tilts on its axis 23.5 degrees. The area of the Earth, that heats up more, is closer to the sun.

43 Seasons When Canada is tilted away from the sun, it is winter. When Canada is tilted towards the sun, it is summer. Spring and Autumn are the in between orbits.

44 Factors that influence weather in different areas. Land Elevation Location- lattitude and longitude The sun Cloud cover Air pressure Earth s orbit (seasons)

45 METEOROLOGY Known as weather science. The term comes from two Greek words meaning high in the air and knowledge.

46 TEMPERATURE Is a measure of how fast air molecules are moving.

47 High Pressure Higher pressure than what is normal for that altitude. The air becomes more dense and sinks, forming regions of high pressure. What do you notice about the air in this region? Brings clear skies and fair weather. The sinking cold air warms as it does so and becomes stable.

48 Low Pressure A low pressure region (depression or cyclone) is caused by rising air. Clouds, rain, and very strong winds occur. Why do you think that is?

49 CLOUDS

50 Precipitation Rain - Water falling in drops from vapour condensed in the atmosphere Drizzle - Very light rain; stronger than mist but less than a shower Dew - Water that has condensed on a cool surface overnight from water vapour in the air Snow - Precipitation falling from clouds in the form of ice crystals Sleet - Partially melted snow (or a mixture of rain and snow) Hail - Precipitate as small ice particles Frost - Ice crystals forming a white deposit (especially on objects outside)

51 Cloud Types Picture taken from:

52 Temperature & Humidity Temperature - Air higher in pressure is usually cooler air and air lower in pressure is usually warmer air. What happens when the two meet? Humidity - How much water is in the air over how much water could fit in the air (right before the water begins to condense out of the air). Dew point - Temperature at which the moisture saturates the air is the dew point.

53 Relative Humidity is a measure of the amount water vapor that is present compared to the amount that could be present at a specific temperature.

54 Wind Pressure and temperature are directly related, wind can be thought of simply as air moving from one temperature or pressure to another area. The greater the difference in pressure or temperature between two areas, the stronger the wind that blows between them will be.

55 SURFACE WINDS Air that expands, becomes less dense, and gets pushed upward. Air at the equator is heated by the rays of the Sun. TRADE WIND (Tropical Easterlies) Steady winds blowing from east to west above and below the equator

56 Westerlies and Easterlies Prevailing Westerlies wind blow from the west. These winds form the boundary between cold air from the poles and milder air closer to the equator. Polar Easterlies wind blow from the east. Near the poles, cold, dense air sinks and flows away form the poles. It is replaced by warmer air flowing in from above.

57 Breezes Land Breeze wind blowing from the land to the sea. Sea Breeze wind blowing from the sea to the land. Mountain Breeze mountain cools rapidly than valleys. The cool heavy air on the mountainside then flows down into the valley. This is the chilly breeze you may feel in the evening. Valley Breeze The air on the mountainside facing the sun therefore becomes warmer than the air over level land. With uneven heating causes a warm breeze to move up the slope.

58 Types of Clouds Type Appearance Characteristics Cirrus Cumulus Stratus Nimbus feathery piled or heaped up/ puffy, like huge towering columns spread out or stretched in layers Rainy/ dark or grayish clouds Fair weather clouds Thin and curly Consists of ice crystals because they are formed under low temperatures at high altitudes Heads of cauliflower with flat bottoms Developed when rising columns of moist air are cooled to the dew point temp. Few hundred meters thick but may extend over thousands of square kilometers. Any cloud that produces precipitation.

59 According to Height Groupings according to Height in the Atmosphere HIGH CLOUDS Mean lower level: 6000 m MIDDLE CLOUDS Mean upper level: 6000 m Mean Lower level: 2000 m LOW CLOUDS Mean upper level: 2000 m Mean Lower level: close to the surface of the Earth CLOUDS OF VERTICAL DEVELOPMENT Mean upper level: that of cirrus clouds or higher Mean Lower level: 500 m Type 1. Cirrus 2. Cirrostratus 3. Cirrocumulus 4. Altocumulus 5. Altostratus 6. Stratocumulus 7. Stratus 8. Nimbostratus 9. Cumulus 10. Cumulonimbus