Pat Arnott, ATMS 749 Atmospheric Radiation Transfer ATMS 749 Atmospheric Radiation Transfer.

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer ATMS 749 Atmospheric Radiation Transfer

Transcript of Pat Arnott, ATMS 749 Atmospheric Radiation Transfer ATMS 749 Atmospheric Radiation Transfer.

Page 1: Pat Arnott, ATMS 749 Atmospheric Radiation Transfer ATMS 749 Atmospheric Radiation Transfer.

Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

ATMS 749 Atmospheric Radiation Transfer

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Electromagnetic Waves … demonstration

Slinky illustrates longitudinal and transverse waves. Polarization cards illustrate Brewster angle reflection from floor tiles with ‘natural light’ incident.

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

CHAPTER 1EMISSION: Birth of Photons

Wave/Photon boson: Polarization.

Linear Polarization: E-field in one direction.

Circular, elliptical polarization: E-Efield rotates due to phase difference between horizontal and vertical components.From: http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/polclas.html

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

More Details on the Polarization States

Circular Polarization

Elliptical Polarization:

The most general representation.

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

The Big Picture, On Average

OLR is balanced by ASR. More flux at the equator and less at the poles drives atmospheric circulations as the planet responds with atmospheric and oceanic circulatiouns, like a heat engine, to relieve the asymmetry.

Why do OLR and ASR have the values shown?

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Energy Transfer From Equator to Poles

Fig. 9.2

Rad

iant

ene

rgy

per

year

---

>

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

The Big Picture, On AverageEnergy pathways are available to the Earth to relieve the ‘burden’ of solar energy. Is it valid to state that the Earth converts solar radiation to IR?

How much of the IR emitted by the surface is directly emitted to space?

Where is most of the solar radiation absorbed?

Do the numbers add up for a radiation balance at the top of the atmosphere?

What roles do conduction, latent heat, and rising air (convection) play in the energy balance?

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

The Big Picture, On Average

SolarIR

heat

How would the numbers change if ‘cloudiness’ increased?

Which numbers change as we increase the CO2 concentration?

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

The Big Picture, Atmospheric radiation drives the global circulation, both in the atmosphere and in the ocean.

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Satellite Images

Geostationary Satellite Images example of visible, IR, and water vapor satellite images.

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

From: http://www.sonoma.edu/users/f/freidel/global/. What’s missing?

Infrared

Atmosphere and Ocean

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Three Choices for Radiation

Emissivity is the same as absorptivity. Source can be visible or infrared radiation, or other wavelengths as well.

Climate consequences of these choices….(from www.ldeo.columbia.edu/.../solar_radiation)

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Earth’s Surface Temperature

Te Earth’s radiative temperatureTs Sun’s radiative temperatureRs Sun’s radiusRse Sun to Earth distancea Earth’s surface solar reflectancet IR transmittance of Earth’s atmosphere.

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Simple Model for Earth’s Atmosphere

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Simple Surface Temperature Calculation Assuming Solar Absorption only at the surface, IR emission by the atmosphere and Earth ’s surface, and IR absorption by the Atmosphere.

S0 = 1376 W/m2=Solar Irradiance at the TOA and =Stefan-Boltzmann constant

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Greenhouse Effect: Greenhouse Effect: from from http://www.dnrec.delaware.gov/ClimateChange/Pages/Greenhouse%20Effect.aspx

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Greenhouse Effect: Greenhouse Effect: from from http://www.dnrec.delaware.gov/ClimateChange/Pages/Greenhouse%20Effect.aspx

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

ManMan’’s Radiative Forcing From year 1750 (IPCC Report)s Radiative Forcing From year 1750 (IPCC Report)

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Gas Concentrations and Projected Temperature

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Where we may be headed…

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Spectrum of Solar Radiation Flux

• The sun emits 41% of its radiation in the visible spectrum, The sun emits 41% of its radiation in the visible spectrum,

• 9% in the ultraviolet spectrum9% in the ultraviolet spectrum

• 50% in the near infrared spectrum50% in the near infrared spectrum

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Earth Light: Spectrum of Outgoing Infrared Radiation

From http://www.lib.utah.edu/services/prog/gould/1998/Figure_5.gif

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Infrared Spectrum from the Atmosphere to the Surface

CO2

O3

H20

CH4

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Spectrum of Solar Radiation Flux

O3

H2O

H2O ,CO2

O2

From Cunningham & Cunningham, 2004,

.1 . 3 .5 1 1.5 2 2.5 3

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

Global Energy Balance

Incoming = 45 +88 = 133

Outgoing = 104 + 24 + 5 = 133

From Cunningham & Cunningham, 2004, Fig. 9.2

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Pat Arnott, ATMS 749 Atmospheric Radiation Transfer

SUNSET NEVADA