Moisture in the Atmosphere Moisture in the Atmosphere and the Results of Energy and the Results of Energy

InputsInputsCreated By:Created By:Mr. KreegerMr. Kreeger

Homework and Page Homework and Page ReferencesReferences

Review Book- Page 574, 579-584Review Book- Page 574, 579-584 Textbook-Pages 485-493Textbook-Pages 485-493

HW#1-1-3 on page 488 of textbook HW#1-1-3 on page 488 of textbook HW#2-1-4 on page 493 HW#2-1-4 on page 493 HW #3-Explain why condensation is a heating HW #3-Explain why condensation is a heating

process and evaporation is a cooling process, process and evaporation is a cooling process, how do these processes affect storm how do these processes affect storm formationformation

Table of ContentsTable of Contents1.1. Moisture and Energy InputMoisture and Energy Input2.2. Air movementAir movement

a)a) Breezes and currentsBreezes and currentsb)b) WindsWinds

1.1. Pressure GradientsPressure Gradients2.2. Local BreezesLocal Breezes3.3. Planetary Convection CellsPlanetary Convection Cells4.4. Planetary WindsPlanetary Winds5.5. Jet StreamsJet Streams

3.3. Clouds Clouds a)a) Formation/Rising and Subsiding airFormation/Rising and Subsiding airb)b) Why they formWhy they formc)c) How are they classifiedHow are they classified

4.4. PrecipitationPrecipitation

1. Moisture and Energy 1. Moisture and Energy Input Input

Moisture in atm Moisture in atm depends ondepends on Evaporation-(LEvaporation-(LG)G) Transpiration- Water Transpiration- Water

released by plantsreleased by plants Evapotranspiration- Evapotranspiration-

All water vapor All water vapor released, large released, large amounts of energy amounts of energy (540cal/gm)(540cal/gm)

2. Air Movement2. Air Movementa) a) Breezes and Breezes and

Currents-Currents- A A breezebreeze is a small local is a small local movement of air movement of air while a while a currentcurrent is a is a vertical movement vertical movement of air (T-of air (T-Storms)Storms)

2b. Winds2b. Winds A wind is a large A wind is a large

horizontal movement horizontal movement of air near the Earth’s of air near the Earth’s surface (named for surface (named for direction from which it direction from which it comes), Ex. SW wind comes), Ex. SW wind means it came from means it came from SW and is moving NE.SW and is moving NE.

1.1. Pressure gradient-The Pressure gradient-The rate of change in rate of change in pressure between 2 pressure between 2 locations (ESRT), closer locations (ESRT), closer the isobars, stronger the isobars, stronger gradient, stronger wind, gradient, stronger wind, further, less gradient, further, less gradient, less wind.less wind.

Activity on WindsActivity on Winds Determine which scenario world Determine which scenario world

have greater winds.have greater winds.a.a. HP=1025mb, LP=990mb, Dist=5kmHP=1025mb, LP=990mb, Dist=5kmb.b. HP=1030mb, LP=996mb, HP=1030mb, LP=996mb,

Dist=7.5kmDist=7.5kmc.c. HP=1022mb, LP=998mb, HP=1022mb, LP=998mb,

Dist=10kmDist=10km

2b2. Local Breezes2b2. Local Breezes DayDay-Land heats faster -Land heats faster

than water than water (LP-Land, HP-Water)-(LP-Land, HP-Water)-Air flows from sea to Air flows from sea to land. (Sea breeze)land. (Sea breeze)

NightNight-Land cools -Land cools faster than water faster than water (HP-Land, LP-Water)-(HP-Land, LP-Water)-Air flows from land to Air flows from land to sea. (Land breeze)sea. (Land breeze)

2b3. Planetary Convection 2b3. Planetary Convection Cells (ESRT Page 14)Cells (ESRT Page 14)

Convection Cell- Cyclic Convection Cell- Cyclic movement due to density movement due to density difference and effects of difference and effects of gravity.gravity.

Variations in Variations in insolation(Why?) result in insolation(Why?) result in unequal heating of earth’s unequal heating of earth’s surface and atm.surface and atm.

Air moves Air moves verticallyverticallypressure belts pressure belts producedproduced Rising air (LP)-Zones of Rising air (LP)-Zones of

convergence (Moist)convergence (Moist) Sinking air (HP)-Zones of Sinking air (HP)-Zones of

divergence (Dry)divergence (Dry)

2b4. Planetary Winds2b4. Planetary Winds(ESRT Page 14)(ESRT Page 14)

If earth did not rotate and If earth did not rotate and was equally heatedwas equally heated 1 1 convection cell would be convection cell would be produced from NP to produced from NP to equator.equator.

BUT>>>>> it is modified BUT>>>>> it is modified by Corilois effect which by Corilois effect which aid in creating a planetary aid in creating a planetary wind system.wind system. At equator-At equator- Wind moves Wind moves

due to trade windsdue to trade winds At mid latitudes-At mid latitudes- move due move due

to prevailing westerliesto prevailing westerlies At high latitudes-At high latitudes- move due move due

to polar easterliesto polar easterlies

2b5. Jet Streams2b5. Jet Streams Winds at high Winds at high

altitudes that control altitudes that control movements of air movements of air masses.masses. Travel at 7-8 miles Travel at 7-8 miles

high( travels at 200 high( travels at 200 kph, travels faster in kph, travels faster in winter)winter)

Migrates from 31N in Migrates from 31N in winter to 50 N in winter to 50 N in summer Why?summer Why?

3. Clouds 3. Clouds a)a) Formation-Condensation, need a Formation-Condensation, need a

surface called cloud condensation surface called cloud condensation nuclei (CCN), can only occur when nuclei (CCN), can only occur when saturation happens (Dewpoint=Air saturation happens (Dewpoint=Air Temp) and a CCN is present i.e. Temp) and a CCN is present i.e. dust, saltdust, salt

• Condensation is a heating process- fuel Condensation is a heating process- fuel for storms (540 cal)for storms (540 cal)

Rising and Subsiding AirRising and Subsiding Air1. RISING AIR EXPANDS AND COOLS

Higher P

Lower P

High P

High P

2. SUBSIDING AIR IS COMPRESSED AND WARMSLower P

Lower P

Higher P (surface)Low P

3b. Why do clouds form3b. Why do clouds formLiftingLifting Cloud TypeCloud Type

Localized convective Localized convective lifting lifting

CumulusCumulus

Topography (orographic Topography (orographic lifting)lifting)

Nimbostratus / lenticularNimbostratus / lenticular

ConvergenceConvergence Cumulus / cumulonimbusCumulus / cumulonimbus

Uplift along weather Uplift along weather fronts (frontal wedging)fronts (frontal wedging)

Nimbostratus/stratus, Nimbostratus/stratus, cumulonimbuscumulonimbus

3b. Why do clouds form 3b. Why do clouds form Cont..Cont..

3c. How are clouds 3c. How are clouds classifiedclassified

Divided into groups Divided into groups based on the based on the height in which height in which they form.they form.

High CloudsHigh Clouds > 6000 m> 6000 m Cold and “dry” - thinCold and “dry” - thin Almost exclusively ice crystalsAlmost exclusively ice crystals

mares’ tails mackerel sky halo

Cirrocumulus

Middle CloudsMiddle Clouds 2000 – 7000 m2000 – 7000 m Mostly water droplets, some ice crystalsMostly water droplets, some ice crystals

No halo, associated with warm fronts, form before storms

Morning Ac means afternoon thunderstorms in summer

Low CloudsLow Clouds <2000 m<2000 m Almost always water droplets (ice and Almost always water droplets (ice and

snow in winter)snow in winter)

Light-moderate rainFor long duration

High pressure,Stabile weather

Fog that doesn’t reach the ground,drizzle

Clouds with Vertical DevelopmentClouds with Vertical Development

Cumulonimbus – unstable atmosphereCumulonimbus – unstable atmosphere Rapid convection brings tops to 12 kmRapid convection brings tops to 12 km Form thunderstorms / lightningForm thunderstorms / lightning

Fair weather Thunderstorms

Summary of cloud typesSummary of cloud types

4. Precipitation4. Precipitation When water droplets or ice crystals When water droplets or ice crystals

grow large enough to fall.grow large enough to fall. TypesTypes

Rain Rain SnowSnow SleetSleet Freezing rainFreezing rain HailHail

Diagrams explaining Diagrams explaining precipitationprecipitationTypeType DiameteDiamete

r (mm)r (mm)Fall Fall Velocity Velocity (km/hr)(km/hr)

Small cloud Small cloud dropletsdroplets

0.010.01 0.010.01

Typical cloud Typical cloud dropletsdroplets

0.020.02 0.040.04

Large cloud Large cloud dropletsdroplets

0.050.05 0.30.3

Drizzle dropsDrizzle drops 0.50.5 77Typical rain dropsTypical rain drops 2.02.0 2323Large rain dropsLarge rain drops 5.05.0 3333

0

5

10

15

20

25

30

35

0 1 2 3 4 5drop diameter (mm)

fall

velo

city

(km

/hr)

Fall Velocity

RainRain Drops of water that Drops of water that

fall from a cloud with fall from a cloud with a diameter of a diameter of >0.5mm>0.5mm

Originates from Originates from nimbostratus or nimbostratus or cumulonimbus cloudscumulonimbus clouds

Begins often as snow Begins often as snow crystals, but also as crystals, but also as raindropsraindrops

SnowSnow Packets of ice Packets of ice

crystalscrystals Low temps Low temps light light

fluffly snow or fluffly snow or “powder”“powder”

Warm temps (-5C) Warm temps (-5C) heavy moist heavy moist snowsnow

SleetSleet

Sleet = small, Sleet = small, translucent translucent particles of iceparticles of ice

Formed as ice, Formed as ice, melted, refrozen as melted, refrozen as ice pelletsice pellets

Freezing RainFreezing Rain Subfreezing air Subfreezing air

near ground is not near ground is not thick enough to thick enough to allow raindrops to allow raindrops to freezefreeze

Raindrops Raindrops supercooledsupercooled

Summary of PrecipitationSummary of Precipitation

HailHail Hard round pelletsHard round pellets Concentric shells of Concentric shells of

ice from traveling ice from traveling up and down a up and down a convective cloudconvective cloud

Produced in large Produced in large cumulonimbus cumulonimbus clouds, speeds = clouds, speeds = 160km/hr160km/hr