Atmospheric RelationshipsAtmospheric Relationships

Created By:Created By:

Mr. KreegerMr. Kreeger

Homework and Page ReferencesHomework and Page References

Page ReferencesPage References Page 487-490, 499-501Page 487-490, 499-501

HomeworkHomework HW #1- Explain why the maximum temperature in any given day occurs HW #1- Explain why the maximum temperature in any given day occurs

after 12pm and why the minimum temperature occurs after midnight-(1 after 12pm and why the minimum temperature occurs after midnight-(1 paragraph)paragraph)

HW #2-Do problems 12,13,14 and 15 on page 490 of textHW #2-Do problems 12,13,14 and 15 on page 490 of textHW #2- Using your reference tables find the Dewpoint and relative HW #2- Using your reference tables find the Dewpoint and relative humidity given the following.humidity given the following.

WB=22C, DB=10CWB=22C, DB=10C WB=13C, DB=8CWB=13C, DB=8C WB=20C, 18CWB=20C, 18C

What do you notice when the about the relative humidity when the What do you notice when the about the relative humidity when the temp and dewpoint are close to one another what do you notice temp and dewpoint are close to one another what do you notice when they are further from each other. Draw a graph dipicting this when they are further from each other. Draw a graph dipicting this relationshiprelationship

Table of ContentsTable of Contents

1.1. Temperature VariationsTemperature Variationsa.a. How is temperature affectedHow is temperature affectedb.b. How the atmosphere receives its energyHow the atmosphere receives its energyc.c. Factors that affect temperatureFactors that affect temperature

1.1. LatitudeLatitude2.2. AltitudeAltitude3.3. Closeness to waterCloseness to water

2.2. Moisture VariationsMoisture Variations3.3. Relative HumidityRelative Humidity4.4. How to determine dewpoint temperatureHow to determine dewpoint temperature5.5. How to determine relative humidity using chartHow to determine relative humidity using chart6.6. Pressure Variations Pressure Variations

1. Temperature Variations1. Temperature Variations

All weather is driven All weather is driven unequal heating of unequal heating of the Earth’s surface. the Earth’s surface. (Remember Specific (Remember Specific Heat)Heat)

Heat Energy is Heat Energy is responsible for responsible for changes in atm changes in atm variablesvariables

1a. How temperature is affected1a. How temperature is affected

Temp- Affected by intensity and duration of Temp- Affected by intensity and duration of insolation (Incoming solar radiation)insolation (Incoming solar radiation) Daily and seasonal changes of temp occur b/c Daily and seasonal changes of temp occur b/c

amount of incoming solar radiation and outgoing re-amount of incoming solar radiation and outgoing re-radiation is differentradiation is different

1b. How the atmosphere receives 1b. How the atmosphere receives its energy its energy

Recieves energy by:Recieves energy by: ConductionConduction Direct Absorption and Direct Absorption and

insolation when light insolation when light passes through atm.passes through atm.

Reradiation from earths Reradiation from earths surfacesurface Related to Related to amount of H2O vapor and amount of H2O vapor and CO2 in atm.CO2 in atm.

Condensation (latent heat) Condensation (latent heat) and Sublimationand Sublimation

Isolines connect equal lines Isolines connect equal lines of tempof temp isotherms isotherms

1c. Factors that affect temperature1c. Factors that affect temperature

1.1. LatitudeLatitude-Higher -Higher latitude lower intensity latitude lower intensity of solar radiation. of solar radiation. (why??)(why??)

2.2. Altitude-Altitude-higher altitude higher altitude lower temp. (Why??)lower temp. (Why??)

3.3. Closeness to H20-Closeness to H20- Coastal regions have Coastal regions have cooler summer temps cooler summer temps and warmer winter and warmer winter temps (Why???)temps (Why???)

• b/c water heats up and b/c water heats up and cools slower than land.cools slower than land.

16

32

48

64

80

16

32

48

64

80

Poll: Compared to the polar areas, why are ...

Poll: The amount of insolation reflected fr...

Poll: On a given day, which factors have th...

Poll: The hottest climates on Earth are loc...

2. Moisture Variations2. Moisture Variations

Moisture content Moisture content changes all the time, changes all the time, water can be found in water can be found in all three phases in all three phases in atm.atm.Ability to hold Ability to hold moisture is directly moisture is directly related to temp. related to temp. (warm air- more (warm air- more moisture, cold air-less moisture, cold air-less moisture)moisture)

2. Moisture Variations Cont..2. Moisture Variations Cont..

When air holds all the water it can at a given tempWhen air holds all the water it can at a given temp saturated (not saturated (not usually the case)usually the case)To obtain saturation, more water must be added without changing To obtain saturation, more water must be added without changing temp or air must be cooled to dewpoint temp. ( The temp at which temp or air must be cooled to dewpoint temp. ( The temp at which condensation occurs), holding all moisture it can at given tempcondensation occurs), holding all moisture it can at given tempAmount of H2O vapor actually present is called absolute humidity Amount of H2O vapor actually present is called absolute humidity ( Greater absolute humidity greater dewpoint temp) ( Greater absolute humidity greater dewpoint temp)

3. Relative Humidity3. Relative Humidity

Comparison between the amount of Comparison between the amount of moisture in the air with the amount moisture in the air with the amount moisture the air can hold at a given temp.moisture the air can hold at a given temp. Ex. If air holding half as much moisture as it Ex. If air holding half as much moisture as it

could be at a given tempcould be at a given temp RH=50% RH=50% If temp rises and moisture content stays the If temp rises and moisture content stays the

same RH decreases.same RH decreases. If temp falls and the moisture content stays If temp falls and the moisture content stays

the same RH increases.the same RH increases.

3. Relative Humidity Cont3. Relative Humidity Cont

RH=(water vapor content/water vapor capacity)x100RH=(water vapor content/water vapor capacity)x100

05

101520253035404550

-40 -30 -20 -10 0 10 20 30 40 50

saturation mixing ratio

Temperature (°C)

Satu

rati

on

m

ixin

g r

ati

o

(gm

/kg

)

Comparison:Comparison:N. MinnesotaN. Minnesota

T = -10°CT = -10°C

RH = 100%RH = 100%

Phoenix ArizonaPhoenix Arizona

T = 25°CT = 25°C

RH = 20%RH = 20%

Which air contains more water vapor?

05

101520253035404550

-40 -30 -20 -10 0 10 20 30 40 50

saturation mixing ratio

Temperature (°C)

Satu

rati

on

m

ixin

g r

ati

o

(gm

/kg

)

4. How to determine Dewpoint 4. How to determine Dewpoint TemperatureTemperature

Use of a sling Use of a sling pyschrometerpyschrometer

Has two Has two thermometers( 1 wet thermometers( 1 wet bulb, 1 dry bulb)bulb, 1 dry bulb) Wet bulb- water Wet bulb- water

evaporates quickly-lower evaporates quickly-lower temptemp

Dry bulb-measures air Dry bulb-measures air temptemp

Can use a dew point Can use a dew point temp charttemp chart

Dew point Temp chartDew point Temp chart

4a. Steps in determining dewpoint 4a. Steps in determining dewpoint temptemp

1.1. Assume DB=10C, WB=6C, diff=4CAssume DB=10C, WB=6C, diff=4C1.1. Locate dry bulb temp (y axis of chart)Locate dry bulb temp (y axis of chart)

2.2. Locate diff between WB and DB temp (X Locate diff between WB and DB temp (X axis of chart)axis of chart)

3.3. Find point where horizontal line from DB Find point where horizontal line from DB reading meets vertical line from diff between reading meets vertical line from diff between WB and DB. That is your dewpoint tempWB and DB. That is your dewpoint temp

5. Determining Relative Humidity 5. Determining Relative Humidity with Chartwith Chart

Steps are the same as determining as Steps are the same as determining as finding dewpoint only diff is you are using finding dewpoint only diff is you are using a different charta different chart

Chart for Relative HumidityChart for Relative Humidity

Try These…

Dry Bulb Wet Bulb R Humidity

DPT

26°C 20 °C

6 °C 5 °C

12 °C 8 °C

18 °C 17 °C

14 °C 14 °C

0 °C -3 °C

57% 17 °C°C

86% 4 °C°C

57% 4 °C°C

91% 16 °C°C

100% 14 °C°C

45% -9 °C°C

More Difficult...

Dry Bulb Wet Bulb R Humidity

DPT

21°C 19°C

11°C 6 °C

17 °C 17°C

2°C -3 °C

9°C 6.5 °C

70°F 60 °F

82% 18 °C°C

45.5% -.5 °C°C

100% 17 °C°C

20% -17 °C°C

69% 3.5 °C°C

52% 11 °C°C(50 °F)(50 °F)21 °C°C 15 °C°C

Try These

DB WB Difference

Dewpoint

RH

-14C -16C

24C 10C

12C 67%

11C 6C

16C 71%

8C -14C

Determining Cloud Base Altitude

• Must know both the Dry Bulb Temperature (DB) and the Dewpoint Temperature (DP)

• Follow the dashed line up the chart this represents the dewpoint and find where it intersects the Solid line which is the dry bulb temperature.

Poll: As the dewpoint temperature of a samp...

Poll: Which gas in the atmosphere has the m...

Poll: An observer measured the air temperat...

Poll: What is the relative humidity when th...

6. Pressure Variations6. Pressure Variations

Force of weight pushing down Force of weight pushing down on a unit area of a surface is on a unit area of a surface is called air pressure or atm called air pressure or atm pressure.pressure.Use a barometer to measure Use a barometer to measure air pressure-tube filed with Hg air pressure-tube filed with Hg when air pressure outside when air pressure outside rises, increase pressure at rises, increase pressure at base tube rises, avg sea level base tube rises, avg sea level pressure =30.0 in of Hg 1013.2 pressure =30.0 in of Hg 1013.2 mb.mb.Use ESRT to convert between Use ESRT to convert between millibars and inches of Hgmillibars and inches of Hg

Try theseTry these !!!! !!!!

MillibarsMillibars Inches of HgInches of Hg

1025.01025.0

29.2529.25

977.0977.0

30.3130.31

1013.21013.2

6. Pressure Variations6. Pressure Variations

On weather maps On weather maps isolines called isobars isolines called isobars connect = lines of air connect = lines of air pressure –show pressure –show pressure patterns pressure patterns over large areas, over large areas, pressure interval pressure interval =4mb=4mb

Ranges from 960mb Ranges from 960mb to 1050mbto 1050mb

Changes in Air PressureChanges in Air Pressure

TemperatureTemperature-- warm air is lighter than warm air is lighter than cold air!cold air!HumidityHumidity-- humid (moist) air is lighter humid (moist) air is lighter than dry air!! Water vapor (Hthan dry air!! Water vapor (H22O) weighs O) weighs less than the N and O gases that it less than the N and O gases that it pushed outpushed outWinds are caused by the Winds are caused by the unequal unequal heatingheating of the atmosphere (remember of the atmosphere (remember that temperature causes changes in air that temperature causes changes in air pressure)pressure)