Study Guide Chapter 6Study Guide Chapter 6

1.1. Describe the hydrologic cycle. List the six Describe the hydrologic cycle. List the six storage areas for water in the hydrologic cycle. storage areas for water in the hydrologic cycle. Explain importance of the hydrologic cycle.Explain importance of the hydrologic cycle.

2.2. How old is the water you drink today?How old is the water you drink today?3.3. What are unique properties of water?What are unique properties of water?4.4. What is meant by the water budget of the earth. What is meant by the water budget of the earth.

Is the hydrosphere an open or closed system?Is the hydrosphere an open or closed system?5.5. Explain the relationship between air temperature Explain the relationship between air temperature

and the ability of air to store water.and the ability of air to store water.6.6. Explain dew point and how it is determined. Explain dew point and how it is determined.

Explain the importance of the dew point.Explain the importance of the dew point.

Study Guide Chapter 6 continuedStudy Guide Chapter 6 continued

7.7. Explain relative humidity. Be able to calculate relative humidity Explain relative humidity. Be able to calculate relative humidity knowing how much water vapor is stored in the air and the knowing how much water vapor is stored in the air and the saturation point of the air. I will give you a specific temperature. saturation point of the air. I will give you a specific temperature.

8.8. What is condensation and evaporation? What are condensation What is condensation and evaporation? What are condensation nuclei. Describe what conditions are necessary for cloud nuclei. Describe what conditions are necessary for cloud formation.formation.

9.9. Describe the three basic forms of clouds.Describe the three basic forms of clouds.

10.10. Compare and contrast the formation of precipitation as rain, snow, Compare and contrast the formation of precipitation as rain, snow, hail, and sleet.hail, and sleet.

11.11. When does precipitation occur?When does precipitation occur?

12.12. Describe adiabatic cooling.Describe adiabatic cooling.

13.13. Describe the rain shadow affect.Describe the rain shadow affect.

14.14.    What conditions are necessary for precipitation. What conditions are necessary for precipitation.

Water-Unique PropertiesWater-Unique Properties

Necessary for all lifeNecessary for all life 73% of Earth’s surface 73% of Earth’s surface Universal solventUniversal solvent Total amount of water on planet remains Total amount of water on planet remains

constantconstant

Hydrologic CycleHydrologic CycleClosed system

4.5 billion years old

Saturation of AirSaturation of Air

Saturation of air means that the air is holding all Saturation of air means that the air is holding all the water vapor that it can at a given temperature. the water vapor that it can at a given temperature.

Water Vapor vs Air TemperatureWater Vapor vs Air Temperature

There are limits to the There are limits to the amount of water vapor a amount of water vapor a parcel of air can holdparcel of air can hold

The warmer the air is the The warmer the air is the greater the amount of greater the amount of water vapor it can holdwater vapor it can hold

What is the saturation What is the saturation point for 21point for 21ooC?C?

Fig. 6.4

Dew Point TemperatureDew Point Temperature

If an unsaturated parcel of air is cooled, it will If an unsaturated parcel of air is cooled, it will eventually reach a temperature where the air will eventually reach a temperature where the air will become saturated. This critical temperature is become saturated. This critical temperature is known as the DEW POINT TEMPERATURE. known as the DEW POINT TEMPERATURE.

3030C and contains 20C and contains 20 g/m g/m33 of water vapor. of water vapor. Saturated or unsaturated? Saturated or unsaturated?

Cool to 21Cool to 21 C. Saturated or unsaturated? C. Saturated or unsaturated?

Lapse RateLapse Rate

When air rises its pressure When air rises its pressure decreases and so it expands decreases and so it expands and cools adiabaticallyand cools adiabatically

Adiabatic Lapse RateAdiabatic Lapse Rate

Dry( unsaturated) adiabatic lapse rate 10Dry( unsaturated) adiabatic lapse rate 1000C/1000mC/1000m LCL (lifting condensation level) meters=T-Td/8*1000 LCL (lifting condensation level) meters=T-Td/8*1000

Where T= temperature of parcel, Td=Dew pt. Temp.Where T= temperature of parcel, Td=Dew pt. Temp. Wet (saturated) adiabatic lapse rate= 5Wet (saturated) adiabatic lapse rate= 500C/1000mC/1000m Rate of warming= 10Rate of warming= 1000/1000m/1000m

5.11

LCL

Fig. 6-20a, p. 167

Rain shadow Effect

windward

leeward

Percent Relative HumidityPercent Relative Humidity

Relative Humidity Relative Humidity is defined as the ratio between amount of is defined as the ratio between amount of water vapor in the air at a given temperature and the water vapor in the air at a given temperature and the maximum amount of water vapor that air can hold at that maximum amount of water vapor that air can hold at that temperature. temperature.

20 g/m20 g/m33 of water vapor and that the air mass is at 30 of water vapor and that the air mass is at 30 C. C. What is the relative humidity?What is the relative humidity?

Relative humidity= 20 /30 *100 = 67 %. This number Relative humidity= 20 /30 *100 = 67 %. This number expresses how close the air is to saturation. expresses how close the air is to saturation.

PsychrometerPsychrometer Desert high or low humidity? Raining relative humidity?Desert high or low humidity? Raining relative humidity?

Sources of Atmospheric MoistureSources of Atmospheric Moisture

TranspirationTranspiration Evaporation as a cooling processEvaporation as a cooling process

CondensationCondensation

How are fogs formed? Clouds are the result of How are fogs formed? Clouds are the result of uplifting of air parcels. uplifting of air parcels.

What is needed to make a cloud?What is needed to make a cloud? Condensation nuclei, some examples?Condensation nuclei, some examples? Low pressureLow pressure MoistureMoisture

Cloud TypesCloud TypesCirrus or wispy

Cumulus- heapUnstable airnimbus=raining

Stratus=layerStable air

Nihttp://eo.ucar.edu/webweather/cloud3.html#Anchor-47857mbus= raining

Fig. 6.9

Strato below 6500ft..

Alto 6500-19700 ft.

Cirro above 19700 ft.

Strato below 6500ft..

Alto 6500-19700 ft.

Cirro above 19700 ft.

Fig. 6-13, p. 161

Forms of PrecipitationForms of Precipitation

RainRain Moderate temperature, fusion of waterModerate temperature, fusion of water Cooler temperatures, ice crystalsCooler temperatures, ice crystals

SnowSnow Snow occurs when a water vapor is frozen Snow occurs when a water vapor is frozen

directly into a solid. The ice crystals form directly into a solid. The ice crystals form around nuclei and make the 6 sided around nuclei and make the 6 sided symmetrical patterns of snowflakes. symmetrical patterns of snowflakes.

HailHail Cumulonimbus cloudsCumulonimbus clouds

Conditions for PrecipitationConditions for Precipitation

Fig. 6.18

Convectional

Cyclonic/Frontal

Orographic

PrecipitationPrecipitation

Where does the heaviest precipitation fall in the Where does the heaviest precipitation fall in the world? Why?world? Why? Figure 6.22Figure 6.22