1. Meteorology
Weather Variable

2. The Water Cycle

3. Factors that Affect Evaporation
Evaporation Simulation: MUST OPEN IN EXPLORER
webContent/Contribution%20Folders/FOSS/multimedia_2E/Variables _MM/activities/whiteboard/evaporation/Main.htm

4. Factors that Affect Evaporation
Temp.: as temperature increases, the evaporation rate increases
2. Humidity: as humidity increases,evaporation rate decreases.
3. Wind: as wind increases, evaporation rate increases.
4. Surface Area: as surface area increases evaporation rate increases.

5. Relative Humidity and Dewpoint
Describe everything that comes to mind when someone says it’s humid.

6. ** Warmer air can hold more water vapor than cooler air.**
Humidity –
is a measure of how much Water
Vapor is in the air.
** Warmer air can hold more water vapor than cooler air.**

7. is “how full” the air is with water vapor, expressed as a %.
Relative Humidity (RH) –
is “how full” the air is with water vapor, expressed as a %.
-RH is a comparison between the amount of moisture in the air with the amount that the air can hold at that temp.
Since warm air expands it can hold more water, lowering its relative humidity

8. **When saturated, warm air contains more water vapor than cold air.**
Saturation:
Occurs when the air contains the maximum amount of water vapor (100%) it can hold at a specific temp. and pressure.
**When saturated, warm air contains more water vapor than cold air.**

9. Condensation may occur.
When the Relative Humidity is 100%
the air is Saturated
Condensation may occur.
Phase change during condensation?
______________ to a ________________

10. Water vapor enters or leaves the air. The temperature changes.
The Relative Humidity changes when:
Water vapor enters or leaves the air.
The temperature changes.
Precipitation take water out of the atmosphere.
Evaporation puts water back into the atmosphere.

11. The Dew Point Temperature is the temp
The Dew Point Temperature is the temp. at which the air becomes saturated with water vapor and condensation occurs.
(or the relative humidity = 100%)
When dewpoint temperature is LOWER than air temperature, condensation will not happen.
When dewpoint temperature is EQUAL to air temperature, condensation happens.
**Dew point temperature is NEVER GREATER than the air temperature**

12. the greater the chance of precipitation
The closer the air temp. is to the dewpoint temp:
the higher the RH
the greater the chance of precipitation
What time has the greatest chance of precipitation?

13. Dew Point Temp. and Relative Humidity are measured using a Sling Psychrometer.

14. Measure Dry Bulb Temperature and Wet Bulb Temperature by swinging instrument for 30 seconds.
Ex. Dry Bulb Temp. = 24 °C.
Wet Bulb Temp. = 20 °C.

15. * Use ESRT pg 12 to find the RH or DP *
Calculate difference between dry and wet bulb temps.
This is called the Wet Bulb Depression.
Ex.: °C °C = 4 °C.
* Use ESRT pg 12 to find the RH or DP *

16. Dry bulb is the air temperature
Relative humidity and Dew point Charts:
Can be found on ESRT pg 12
Dry bulb is the air temperature

17. Wet bulb is the temperature of a thermometer that has a wet “sock” attached to it
The wet bulb depression is the difference between the two, it shows how much evaporation has taken place,

18. Dry Bulb= 20 °C Wet Bulb Depression= 4 °C

19. How are clouds and precipitation related?
How Are Clouds Formed?
How are clouds and precipitation related?

20. Formation of Clouds
1. Form when warm moist air rises in the atmosphere
and is cooled to its Dew Point Temperature.
2. Water vapor condenses around small solid particles (floating dust or salt) called condensation nuclei.
3. Tiny droplets then float
in the air.
Making
a Cloud Video

21. Orographic lifting:
occurs when mountains act as barriers to the flow of air, forcing the air to ascend.
Air is pushed over the mountain, is cooled and then condenses into a cloud.

22. Orographic lifting:
Windward
Cool
&
Wet
Leeward
Warm
&
Dry

23. **When air expands, it cools, and when air is
(as it rises in the atmosphere)
**When air expands, it cools, and when air is
compressed, it warms.**
(as it sinks in the atmosphere)

24. Clouds can help predict weather, each type of cloud means something different is happening in the atmosphere
Cloud Types:
Cumulus clouds, fly puffy and white. Some look like cottonballs, fluffy and light. Nice Weather!

25. The Nimbus clouds fly dark and low When you see them, it means rain or snow.

26. Cirrus clouds are feathery and white They’re made of ice and fly at a great height

27. Stratus clouds have a layered look stacking clouds like a book.

28. Fog is the lowest cloud you can see Maybe a cloud that got caught in a tree.

29. FOG Is a cloud in contact with the ground.
Most types of fog form when the relative humidity reaches 100% at ground-level.

30. Water droplets or ice crystals can grow to heavy to float in a cloud and fall to the Earth as PRECIPITATION

31. What are the Effects of Air Pressure on Weather?

32. Air Pressure:
The force or weight of the atmosphere pushing down on the earth in all directions.

33. Air Pressure is measured using a Barometer.

34. ** A decreasing barometer means the weather will be cloudy and wet.
**When air pressure decreases, so does the height of the mercury column.**
** A decreasing barometer means the weather will be cloudy and wet.
LOW AND LOUSY
**When air pressure increases, the mercury in the tube rises. **
** An increasing barometer means the weather will be dry and sunny.
HIGH AND DRY

35. Factors that Affect Pressure
Temperature As temperature Increases, air pressure decreases.
Warm air
expands (less dense)
has less pressure
Rises in the atmosphere
Cold air
Contracts (more dense)
has more pressure
sinks in the atmosphere

36. Altitude: As altitude increases air pressure decreases.
Air becomes less dense with increasing altitude
Pressure ALWAYS decreases as you move up in the atmosphere.

37. Humidity : As humidity increases air pressure decreases.
Moist air is lighter then dry air.
“ Dry air weighs more then moist air”

38. Best conditions to hit a homerun?
Warm, moist day at a high elevation

39. Air Pressure page 13 ESRT
According to the Earth Science Reference Tables, an air pressure of inches of mercury is equal to:
a) 1017 mb
b) 1019 mb
c) 1021 mb
d) 1023 mb
Locate the chart in the Earth Science Reference Tables that shows pressure scales in millibars and inches. The right-hand column shows atmospheric pressure in inches of mercury. An air pressure of is halfway between 30.1 and Locating this point and reading over to the left-hand column yields an air preaure of 1,021 millibars.

40. How do pressure systems cause winds?
List 3 characteristics for warm air and cold air.

41. Rises in the atmosphere Cold air contracts has more pressure
Temperature
Warm air
expands
has less pressure
Rises in the atmosphere
Cold air
contracts
has more pressure
sinks in the atmosphere
Straight from your air pressure notes

42. Wind – is the movement of air due to differences in air pressure
Air moves from HIGH pressure to LOW pressure

43. Warm humid air rises in the center Wind blows COUNTERCLOCKWISE and IN
Pressure Systems
Low Pressure System
(AKA cyclone )
Warm humid air rises in the center
Wind blows COUNTERCLOCKWISE and IN

44. Cool dry air sinks in the center Wind blows CLOCKWISE and OUT
High Pressure System
(AKA anticyclones )
Cool dry air sinks in the center
Wind blows CLOCKWISE and OUT

45. Air moves from HIGH to LOW
L H
Draw picture in your notebook

46. There are two basic wind measurements:
Measuring Wind -
There are two basic wind measurements:
Direction & Speed

47. Wind is always named for the direction it comes from.
Wind Direction
Measured using a wind vane
If it blows more often from one direction it is called a prevailing wind
Wind is always named for the direction it comes from.
In the US, the westerlies consistently move weather west to east.

48. Measured using an anemometer
Wind Speed
Measured using an anemometer

49. Strength of Wind: The greater the difference in pressure (gradient) the stronger the winds.
Isobars: connect points of equal air pressure.
*the closer the isobars the greater the wind speed

50. What causes Local Winds?
What causes wind?

51. Wind – is the movement of air due to differences in air pressure

52. Local winds are caused by variations in surface composition.
Ex – Land vs. Water

53. Every object has it’s own specific heat some are listed on ESRT pg 1
Specific heat is the amount of energy needed to change a substance 1 degree.
Every object has it’s own specific heat some are listed on ESRT pg 1

54. Liquid Water has a highest specific heat
Water needs more energy & more time to heat up or cool down

55. Land heats up faster lowering the pressure
Sea Breeze
Land heats up faster lowering the pressure
The air flows from the water to the land.
Happens during the day.

56. Land cools down faster, increasing the pressure
Land Breeze
Land cools down faster, increasing the pressure
The air flows from the land to the water.
Happens during at night.
Copy diagram into your notebook