1. Weather

2. Atmospheric layers
Troposphere – weather occurs here, closest to ground, colder as you rise; ends with the tropopause.
Stratosphere – jet stream here; from tropopause up warmer as you rise; ozone layer is here. Ends with stratopause.
Mesosphere – ice clouds that burn up meteoroids; from stratopause up , colder as you go up. Ends with mesopause.
Thermosphere – hot layer, made of two layers. Ionosphere where satellites and auroras are; and Exosphere marking the end of the atmosphere at 800 km.

3. Review 13: Weather Meteorologist – scientists who study the weather.
What direction do most weather systems travel in the U.S.?

4. Defining weather…
Weather is the daily conditions of the atmosphere

5. Heat Energy and the Atmosphere
The Sun’s energy is mostly absorbed by the Earth but some is reflected back into space

6. The Greenhouse Effect
Caused by the increased amount of CO2 which is placed there through burning fossil fuels.

18. arctic cod
Krill?, amphipods?
amphipod
black guillemot
copepod

19. harp seal
bearded seal
ribbon seal
walrus
spotted seal
ringed seal
hooded seal

20. GREENHOUSE EFFECT

21. Air pressure
Air pressure if the force of air pressing down on the Earth’s surface
Highest at sea level.
As elevation increases (you go up) pressure and density decreases (air is thinner).

22. Air Masses
A large body of air that has properties similar to the part of the Earth’s surface over which it develops.

24. Air Mass Map

25. Fronts
A boundary between two air masses of different density, moisture, or temperature.

26. Cold Front

27. Warm Front

28. Occluded Front

29. Stationary Front

30. Severe Weather occurs when two different fronts collide.
Thunderstorms
Lightning
Tornadoes

31. How do storms begin?

32. Types of storms…
Storms –violent disturbance in the atmosphere. Marked by sudden change in air pressure and rapid air movement; two different fronts collide (warm meets cold)

33. Winter weather…

34. Thunderstorms
Thunderstorms – cold meets warm front.

35. Cyclones and Anticyclones?
Cyclones – area of low pressure that cause rainy stormy weather.
Anticyclones – high pressure area that causes dry clear fair weather.

36. Hurricanes and Typhoons are the same thing…

37. More about tornadoes… Great Plains – “tornado alley”.
Average diameter - .4 km
Length traveled – 6 km for only a few minutes but winds can still reach more than 350 km/hour.

38. More Severe Weather
Hurricanes
Blizzards

39. Severe Weather Safety Watches- conditions are favorable
Warnings- conditions already exist
Examples- Tornadoes, Flooding, Thunderstorms, Blizzards, Winter Mixes and Hurricanes

41. Lightning – opposites attract
Lightning – opposites attract. Will strike the tallest positively charged object.

43. Tornado Alley

44. Fujita Scale

45. Hurricane

46. Saffir-Simson Scale measures Hurricanes

47. NWS Two sources of forecasting weather
Data collected from upper atmosphere
Data collected on the Earth’s surface

48. Weather Station Model

49. Isobars Isobars-connect points of the “same”
Examples: temperature and wind speed
The further away the lines the lower the wind speed

50. Winds Wind is caused by unequal heating of the atmosphere
Winds travel from high to low pressure
Winds curve to the right in the N hemisphere and to the left in the S hemisphere called the Coriolis effect

51. Local winds blow in all directions and in short distances.
Land and Sea breezes
Local winds blow in all directions and in short distances.
You feel the air moving from water to land during the day
Warm air rises over the land and moves over the water
Cool air sinks and travels toward the land
You feel the air moving from land to the water at night
Warm air rises over the water and moves toward the land
Cool air sinks toward the land

52. Jet Stream
jet stream - strong, high speed wind that blows from west to east.
Located in the stratosphere.

53. Moisture in the Air Humidity - Water vapor or moisture in the air.
Dew Water – water vapor becomes liquid water as it condenses.
Condensation forms clouds as water vapor rises and cools.

54. MOISTURE

55. Weather
High-pressure system – when cold air sinks to the ground, warms up, and absorbs water vapor, causing sunny skies.
Low-pressure system – when warm air rises higher in the sky, causing water vapor to cool and form clouds and precipitation.
Predict what will happen if a high-humidity air mass located over an ocean moves inland and up a mountain slope. Why do you think so?

56. Movement of Pressure Systems
High Pressure moves clockwise and outwardly.
Low Pressure moves counterclockwise and inwardly.

57. Cirrus – highest clouds Indicate rain/snow in next 24 hours
Cumulus – bright white wads of cotton
seen with fair weather

58. More on clouds Stratus – form gray sheets that spread across the sky
Bring heavy mist, snow
or drizzle. Cause fog.
Cumulonimbus – largest clouds. Bring heavy rain, high
winds, hail and tornadoes.
Describe the clouds you see outside.
Do they fit any of the categories?

59. Precipitation types
Hail – when a raindrop freezes and forms an icy ball before falling to the ground.
Sleet – when a raindrop falls from a cloud and passes through below-freezing air making a slushy blob.
Snow – when ice crystals form in clouds and fall to the ground without melting.

60. Weather
Make a prediction. What kind of precipitation will fall if there are:
Below-freezing temperatures in the clouds
Temp. barely above freezing on the ground?
Describe the air temperature, precipitation, winds, and humidity during:
Winter? Spring?
Summer? Fall?

61. Weather Wind speed is described in miles per hour.
Wind direction is the direction from which the wind blows.
A north wind comes from the north.
The tail points to where the wind is coming from.
The barbs on the tail show the speed of the wind. More barbs – faster wind
The dot points to the direction the wind is going.

62. Tools to gather data about the weather:
Review 13: Weather
Tools to gather data about the weather:
Thermometer – measures temperature
Anemometer – measures wind speed

63. Tools to gather data about the weather:
Review 13: Weather
Tools to gather data about the weather:
Rain Gauge – measures the amount of precipitation
Barometer – measures air pressure
Weather Vane –
indicates wind direction

64. Odd-shaped clouds

65. Even more…

66. Sun dogs

67. Weather Stations & Weather Map Symbols

69. Temperature
Top left number shows the temperature

70. Weather Symbol
The symbol between the two numbers on the left indicate what the weather is in terms of precipitation.

71. Notice how more symbols indicate intensity
More snow flake symbols =more snow
More rain symbols = heavy rain

72. The number on the bottom left shows the temperature the air must be for condensation to occur or the Dew Point.
Humidity is a factor of the dew point.
This number will be lower than the actual temperature.
Remember cold air can’t hold moisture like warm air
Dew Point

73. Cloud Cover
The percentage of the circle that is shaded in reflects the percentage of cloud cover in the sky
Similar to a pie chart

74. Air Pressure
This number is displayed on the top right of the weather symbol
When the # is high or rising, the weather is fair because the pressure is high
When the # is low or dropping, the weather is rainy, because the pressure is low

75. Wind Barb
This shows the direction of the wind, it will point in the direction the wind is coming from, this shows the wind coming from the Southeast
The # of lines and/or triangles indicates the speed of the wind

76. The wind barb points in the direction it is coming FROM.
Stronger winds have more flags, or marks

77. Fronts on a weather map Warm occluded Cold Stationary
The symbols point in the direction that the front is moving towards
Pressure symbols:

78. Isobars: connect areas with equal air pressure The distance between the isobars is called the pressure gradient
The closer the isobar lines, the greater the change in air pressure, and the greater/faster the winds speeds.
High pressure systems bring clear/sunny weather and wind flows out and clockwise (right)
Low pressure systems bring overcast/stormy weather and wind flows in and counter-clockwise (left)