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ATM OCN 100 - Fall 2000 ATM OCN 100 - Fall 2000 LECTURE 8LECTURE 8

ATMOSPHERIC ENERGETICS:ATMOSPHERIC ENERGETICS: RADIATION & ENERGY BUDGETSRADIATION & ENERGY BUDGETS

A. INTRODUCTION:A. INTRODUCTION:– What maintains life?What maintains life?– How does Planet Earth maintain a habitable How does Planet Earth maintain a habitable

environment?environment?

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B. ENERGY (HEAT) BUDGETSB. ENERGY (HEAT) BUDGETS

Energy budget philosophyEnergy budget philosophy

INPUT = OUTPUT + INPUT = OUTPUT + STORAGE STORAGE

Planetary annual energy budget Planetary annual energy budget

– Short wave radiation components Short wave radiation components

– Long wave radiation components Long wave radiation components

– Non radiative components Non radiative components (where)...(where)...

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Background - The Earth, The Sun &Background - The Earth, The Sun &The Radiation Link The Radiation Link

INPUT -- Solar RadiationINPUT -- Solar Radiation– From Sun radiating at temperature From Sun radiating at temperature 6000 K; 6000 K; – Peak radiation Peak radiation m;m;– Solar Constant Solar Constant 22cal/cmcal/cm22/min or 1370 W/m/min or 1370 W/m22

OUTPUT -- Terrestrial radiationOUTPUT -- Terrestrial radiation– Emitted from earth-atmosphere system;Emitted from earth-atmosphere system;– Radiating temperature Radiating temperature – Peak radiation region Peak radiation region m.m.

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Planetary Radiative Energy Budget Planetary Radiative Energy Budget From Geog. 101 UW-Stevens PointFrom Geog. 101 UW-Stevens Point

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PLANETARY ENERGY BUDGETSPLANETARY ENERGY BUDGETSShort Wave ComponentsShort Wave Components

Disposition of solar radiation in Disposition of solar radiation in Earth-atmosphere systemEarth-atmosphere system

– ReflectedReflected

– ScatteredScattered

– AbsorbedAbsorbed

– TransmittedTransmitted ImplicationsImplications

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PLANETARY ENERGY BUDGETSPLANETARY ENERGY BUDGETSLong Wave ComponentsLong Wave Components

Disposition of long radiation inDisposition of long radiation in Earth-atmosphere system Earth-atmosphere system

– EmittedEmitted

– AbsorbedAbsorbed

– TransmittedTransmitted

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PLANETARY ENERGY BUDGETSPLANETARY ENERGY BUDGETSLong Wave Components Long Wave Components (con’t.)(con’t.)

Atmospheric Atmospheric oror “Greenhouse” Effect “Greenhouse” Effect– BackgroundBackground– ““Greenhouse Gases” [HGreenhouse Gases” [H22O, COO, CO22, CH, CH44]]

ImplicationsImplications

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PLANETARY ENERGY BUDGETSPLANETARY ENERGY BUDGETSNon-Radiative ComponentsNon-Radiative Components

Disposition of non-radiative fluxes in Disposition of non-radiative fluxes in Earth-atmosphere systemEarth-atmosphere system

Types of non-radiative fluxesTypes of non-radiative fluxes

– Sensible heat transportSensible heat transport– Latent Heat transportLatent Heat transport

ImplicationsImplications

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PLANETARY ENERGY BUDGETS PLANETARY ENERGY BUDGETS (con’t.)(con’t.)

ANNUAL AVERAGEANNUAL AVERAGE

Input = OutputInput = Output

Absorbed solar = Emitted Absorbed solar = Emitted terrestrialterrestrial

LATITUDINAL DISTRIBUTIONLATITUDINAL DISTRIBUTION– Input & Output CurvesInput & Output Curves– Energy surplus & deficit regionsEnergy surplus & deficit regions– Meridional energy transport inMeridional energy transport in

Atmosphere & Oceans Atmosphere & Oceans

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OCEAN CURRENTSOCEAN CURRENTS

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ENERGY BUDGETS ENERGY BUDGETS (con’t.)(con’t.)

LOCAL ENERGY BUDGETSLOCAL ENERGY BUDGETS THE FORCING (Energy Gain)THE FORCING (Energy Gain)

– Radiative ControlsRadiative Controls LatitudeLatitude CloudsClouds

– Air Mass ControlsAir Mass Controls Warm Air Advection & Cold Air AdvectionWarm Air Advection & Cold Air Advection

THE RESPONSETHE RESPONSE– Temperature & Temperature VariationsTemperature & Temperature Variations

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ENERGY BUDGETS ENERGY BUDGETS (con’t.)(con’t.)

FACTORS TO CONSIDERFACTORS TO CONSIDER in the Thermal Response in the Thermal Response– Albedo (reflectivity)Albedo (reflectivity)– ConductivityConductivity– Specific HeatSpecific Heat

Quantity of heat required to change Quantity of heat required to change temperature of a unit mass of substance by temperature of a unit mass of substance by 1 Celsius degree. 1 Celsius degree.

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Thermal Conductivity Example: Thermal Conductivity Example: Change in Snow Cover Change in Snow Cover

See Figure 3.6, Moran & Morgan (1997)See Figure 3.6, Moran & Morgan (1997)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.00000 0.00100 0.00200 0.00300 0.00400 0.00500

HEAT CONDUCTIVITY in SNOW [cal/cm2/sec/Co/cm]

SN

OW

DE

NS

ITY

[gm

/cm

3]

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TEMPERATURE RESPONSETEMPERATURE RESPONSE forfor substances with differing specific substances with differing specific

heatsheatsSee Table 3.2, Moran & Morgan (1997)See Table 3.2, Moran & Morgan (1997)

TEMPERATURE RESPONSE TO ENERGY ADDED

___ WATER ___ WOOD ___ SAND ___ AIR

0.0

5.0

10.0

15.0

0.0 0.5 1.0 1.5 2.0

HEAT ADDED [calories per gram]

TE

MP

ER

AT

UR

E o

f S

YS

TE

M [

de

g C

]

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ENERGY BUDGETSENERGY BUDGETS (con’t) (con’t)

Local energy budgets Local energy budgets Features of local energy budgetsFeatures of local energy budgets

– AnnualAnnual Summer maximum temperatureSummer maximum temperature Winter minimum temperatureWinter minimum temperature

– DiurnalDiurnal Afternoon maximum temperatureAfternoon maximum temperature Pre-dawn minimum temperaturePre-dawn minimum temperature

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