1. Quiz Chapter 24 1. Sublimation 2. Latent heat 3. Humidity 4. Saturated 5. Relative humidity 6. Psychrometer 7. Hair hygrometer 8. Specific humidity 9. Dew point 10. Dew

2. 12/13/2015 describe how relative humidity is measured Turn to page 482

3. This is due at the end of class Warm up question: How does relative humidity measure humidity Exit: What is a dew point Homework: Questions on page 483 – due 2/4

4. Essential Question Describe what happens when the temperature of air decreases at or below the dew point Homework Questions on page 483 – due 2/4.

5. Chapter 24 1. Sublimation 2. Latent heat 3. Humidity 4. Saturated 5. Relative humidity 6. Psychrometer 7. Hair hygrometer 8. Specific humidity 9. Dew point 10. Dew 11. Frost 12. Condensation nuclei 13. Convective cooling 14. Adiabatic 15. Advective cooling 16. Stratus clouds 17. Cumulus clouds 18. Cirrus clouds 19. Radiation fog 20. Advection fog 21. Upslope fog 22. Steam fog

6. Chapter 24 23. Sleet 24. Glaze ice 25. Hail 26. Coalescence 27. Supercooling 28. Freezing nuclei 29. Cloud seeding 30. Rain gauge Video Link Video Link Video Link Video Link experiments experiments experiments

7. Chapter 24 Section 1 Objectives Explain how water vapor enters the air. Explain how water vapor enters the air. Explain the meaning of humidity and describe how it is measured. Explain the meaning of humidity and describe how it is measured. Describe what happens when the temperature of air decreases at or below the dew point. Describe what happens when the temperature of air decreases at or below the dew point.

8. Notes chapter 24 section 1 Atmospheric Moisture Atmospheric Moisture Water in the air is called water vapor: it is tasteless, odorless, and invisible gas Water in the air is called water vapor: it is tasteless, odorless, and invisible gas Water in the air can also be in the form of ice or water droplets Water in the air can also be in the form of ice or water droplets

9. Notes chapter 24 section 1 Heat energy and water Heat energy and water Water in the form of ice is held in a CRYSTALLINE STRUCTURE Water in the form of ice is held in a CRYSTALLINE STRUCTURE Evaporation occurs when water molecules rotate and vibrate fast enough to overcome forces of attraction Evaporation occurs when water molecules rotate and vibrate fast enough to overcome forces of attraction Can ice become vapor without first becoming water? Can ice become vapor without first becoming water? –Sublimation: process where water in a solid form (ice) goes directly to a gas phase

10. Notes chapter 24 section 1 Heat energy and water Heat energy and water Though most water enters atmosphere through EVAPORATION, some water does enter through SUBLIMATION Though most water enters atmosphere through EVAPORATION, some water does enter through SUBLIMATION –Where does most sublimation occur? (hint: where is there a lot of ice???) Latent Heat: “Hidden” heat Latent Heat: “Hidden” heat –Given off during evaporation –Taken out during freezing

11. Notes chapter 24 section 1 Humidity Humidity Humidity: amount of water in the atmosphere Humidity: amount of water in the atmosphere –When the air CANNOT hold anymore water, the air is considered to be SATURATED The higher the temperature of air – THE MORE WATER IT CAN HOLD The higher the temperature of air – THE MORE WATER IT CAN HOLD –As the temperature decreases, so does the ability of air to hold water vapor

12. Notes chapter 24 section 1 Relative Humidity Relative Humidity Relative Humidity is a RATIO Relative Humidity is a RATIO MASS OF WATER IN AIR POTENTIAL MASS OF WATER Potential mass of water that air can hold changes with the temperature of the air Potential mass of water that air can hold changes with the temperature of the air –Hotter - more water vapor content –Colder – less water vapor content

13. Notes chapter 24 section 1 Measuring Relative Humidity Measuring Relative Humidity Wet Bulb – Dry Bulb Method Wet Bulb – Dry Bulb Method –Dry bulb takes temperature of air with the amount of moisture present –Wet Bulb takes temperature of air SIMULATING A SATURATED ATMOSPHERE –Using both measurements, estimate humidity based on Relative Humidity Chart Tool: PSYCHOMETER Tool: PSYCHOMETER

14. Notes chapter 24 section 1 Specific Humidity Specific Humidity Express the amount of water in the air in g/kg Express the amount of water in the air in g/kg It is not affected by temperature or pressure. It is not affected by temperature or pressure.

15. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 1 Dew point Dew point This is the temperature at which air is saturated with water. Below this temperature liquid or solid water forms. This is the temperature at which air is saturated with water. Below this temperature liquid or solid water forms. Dew may also form on a surface via condensation Dew may also form on a surface via condensation If the dew point is below freezing frost will form If the dew point is below freezing frost will form

16. Chapter 24 Section 2 Objectives List the conditions that must exist for a cloud to form. List the conditions that must exist for a cloud to form. Identify the types of clouds. Identify the types of clouds. Describe four ways fog may form. Describe four ways fog may form.

17. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Clouds and fog Clouds and fog Are visible water droplets in the atmosphere Are visible water droplets in the atmosphere Clouds and fog are the same, altitude is the only difference. Clouds and fog are the same, altitude is the only difference.

18. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Cloud formation Cloud formation The water needs something to condense onto, dust. The water needs something to condense onto, dust. The air must be at or below the dew point to cause cloud formation or saturated. The air must be at or below the dew point to cause cloud formation or saturated.

19. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Convective cooling Convective cooling As air rises it expands and cools, due to the release of energy. As air rises it expands and cools, due to the release of energy. This process of cooling and heating to rising and falling air is called adiabatic This process of cooling and heating to rising and falling air is called adiabatic

20. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Convective cooling Convective cooling Warms at a steady rate of 1 0 C for every 100 M the air descends. The cooling is effected by the condensation process and averages.7 0 C per 100 M the air rises. Warms at a steady rate of 1 0 C for every 100 M the air descends. The cooling is effected by the condensation process and averages.7 0 C per 100 M the air rises.

21. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Convective cooling Convective cooling The level at which the clouds form is called the condensation level. The level at which the clouds form is called the condensation level. This starts at the bottom of the cloud and further condensation allow the clouds to form up. This starts at the bottom of the cloud and further condensation allow the clouds to form up.

22. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Forceful Lifting Forceful Lifting Can be caused by air moving over a mountain range. Can be caused by air moving over a mountain range. It can also be caused by warm air pushing over a cold air mass. It can also be caused by warm air pushing over a cold air mass.

23. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Temperature changes Temperature changes The mixing of two or more moist air masses with different air temperatures may be enough to get below the dew point. The mixing of two or more moist air masses with different air temperatures may be enough to get below the dew point.

24. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Advective cooling Advective cooling This is when warm moist air passes over a cold body of water or land mass, the heat is absorbed (dropping below the dew point) and low clouds form or fog. This is when warm moist air passes over a cold body of water or land mass, the heat is absorbed (dropping below the dew point) and low clouds form or fog.

25. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Classification of clouds Classification of clouds By form and altitude By form and altitude Forms: Stratus, Cumulus and Cirrus. Forms: Stratus, Cumulus and Cirrus. Altitude groups: Low is up to 2,000 M, Middle is 2,000 to 6,000 M and High is above 6,000 M Altitude groups: Low is up to 2,000 M, Middle is 2,000 to 6,000 M and High is above 6,000 M

26. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Stratus Clouds Stratus Clouds Are sheet like or layered, they are low to the earth surface and cover large areas of the sky. Are sheet like or layered, they are low to the earth surface and cover large areas of the sky. Formed when warm air is above cool air, give very little rain. Formed when warm air is above cool air, give very little rain. Two other types: nimbostratus are dark and give heavy rain or snow, altostratus form at middle latitudes and little rain Two other types: nimbostratus are dark and give heavy rain or snow, altostratus form at middle latitudes and little rain

27. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Cumulus Clouds Cumulus Clouds Are the puffy or popcorn clouds, if the form at the middle they are altocumulus and at lower levels are stratocumulus and cumulus. Are the puffy or popcorn clouds, if the form at the middle they are altocumulus and at lower levels are stratocumulus and cumulus. If there are strong rising winds a cumulonimbus forms and can produce thunder, lighting and rain. If there are strong rising winds a cumulonimbus forms and can produce thunder, lighting and rain.

28. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Cirrus Clouds Cirrus Clouds These are the feathery or curly clouds at high altitudes. These are the feathery or curly clouds at high altitudes. Normally made of ice crystals, that can cause a halo to form around the sun or moon. Normally made of ice crystals, that can cause a halo to form around the sun or moon.

29. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 2 Fog Fog Radiation fog or ground fog forms close to the ground as it gives off the heat from the day, more common in valleys were the cold air can collect. Radiation fog or ground fog forms close to the ground as it gives off the heat from the day, more common in valleys were the cold air can collect. Advection fog forms when warm moist air pushes over a colder surface. Advection fog forms when warm moist air pushes over a colder surface. Upslope fog is cause by warm air moving uphill and steam fog is when warm air moves over a colder body of water. Upslope fog is cause by warm air moving uphill and steam fog is when warm air moves over a colder body of water.

30. 12/13/2015 list the conditions that must exist for a cloud to form Chapter 24 section 3 essential questions Describe the various types of liquid and solid precipitation. Describe the various types of liquid and solid precipitation. Compare the two processes that cause precipitation Compare the two processes that cause precipitation Describe how rain may be produced artificially Describe how rain may be produced artificially Describe how precipitation is measured Describe how precipitation is measured

31. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 3 Precipitation Precipitation Moisture that falls from the sky; either as a liquid or solid. ( rain, snow, sleet and hail) Moisture that falls from the sky; either as a liquid or solid. ( rain, snow, sleet and hail)

32. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 3 Forms of precipitation Forms of precipitation Liquid – rain Liquid – rain A drizzle – drops less then.5 mm are close together and fall slowly. A drizzle – drops less then.5 mm are close together and fall slowly. Raindrops -.5 mm to 5 mm, can be a mist to heavy rains as in a storm. Raindrops -.5 mm to 5 mm, can be a mist to heavy rains as in a storm.

33. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 3 Forms of precipitation Forms of precipitation Snow – most common solid form. Smaller in size in lower temp because of lack of moisture. Snow – most common solid form. Smaller in size in lower temp because of lack of moisture. Sleet – rain freezes in the air as it falls to the ground. Sleet – rain freezes in the air as it falls to the ground. If it freezes when it hits the ground it forms sheet ice or glaze ice. If it freezes when it hits the ground it forms sheet ice or glaze ice.

34. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 3 Forms of precipitation Forms of precipitation Hail – lumps of ice that are spherical or irregular in shape. Hail – lumps of ice that are spherical or irregular in shape. Form in normally in cumulonimbus clouds, rain gets pushed through a freeze layer and wind currents push it up and down several times. Form in normally in cumulonimbus clouds, rain gets pushed through a freeze layer and wind currents push it up and down several times.

35. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 3 Causes of precipitation Causes of precipitation Water droplets are normally small enough to stay in the air. Water droplets are normally small enough to stay in the air. If the size increases 100 times from 20 micrometers, they will begin to fall If the size increases 100 times from 20 micrometers, they will begin to fall

36. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 3 Coalescence Coalescence Rain drop size is determined by the size of the nuclei. Rain drop size is determined by the size of the nuclei. As droplets collide they get larger until it comes down as rain. As droplets collide they get larger until it comes down as rain. Coalescences is how rain forms in the tropics. Coalescences is how rain forms in the tropics.

37. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 3 Supercooling Supercooling Water temps may go as low as -10 0 C. Water temps may go as low as -10 0 C. They do not freeze unless they have a freezing nuclei to attach to. They do not freeze unless they have a freezing nuclei to attach to. Once the process starts, crystals form quickly and fall as snow or rain Once the process starts, crystals form quickly and fall as snow or rain

38. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 3 Cloud seeding Cloud seeding They add freezing nuclei to the cloud like: silver iodine (from flares or burners) or powdered dry ice. They add freezing nuclei to the cloud like: silver iodine (from flares or burners) or powdered dry ice. Conflicting evidence on effect, it may someday help end droughts and control storms. Conflicting evidence on effect, it may someday help end droughts and control storms.

39. 12/13/2015 list the conditions that must exist for a cloud to form Notes chapter 24 section 3 Measuring precipitation Measuring precipitation Three types: a wide funnel attached to a cylindrical container, one that dumps when it reaches a certain level, and the last weighs the amount of water in the bucket. Three types: a wide funnel attached to a cylindrical container, one that dumps when it reaches a certain level, and the last weighs the amount of water in the bucket. Only measure in one small area. Only measure in one small area. Snow is measured by depth and water volume, average is 10cm of snow per 1cm of water Snow is measured by depth and water volume, average is 10cm of snow per 1cm of water