cli t d r di ticlimate and radiation

Cli t d R di tiCli t d R di tiClimate and RadiationClimate and Radiation

Yuk Ling YungYuk Ling YungGPS CaltechGPS CaltechGPS CaltechGPS Caltech

Presentation at CaltechPresentation at CaltechAug 31 2009Aug 31 2009gg

Today’s OutlineToday’s OutlineToday s OutlineToday s Outline

What is Radiation? (Review)What is Radiation? (Review)Wh t i th G h Eff t?Wh t i th G h Eff t? （（R i )R i )What is the Greenhouse Effect?What is the Greenhouse Effect? （（Review)Review)GCM Prediction of FutureGCM Prediction of Future (IPCC)(IPCC)Use of Spectral Data ConclusionsConclusions

Blackbody Radiation

( )3

2

2 11h kT

hB Tc eν ν

ν=

−1c e

Goody and Yung (1995)

SSun surface

Center of sun

Atmosphere Space

T

Atmosphere : Processor of energy

Ts

=

Sunlight = driver ofChemistry dynamics{

288Sunlight driver of dynamics

biology{8

K

Process Total Power (Watts)

Sunlight 2 X 1017Sunlight 2 X 10

Seawater evaporation 3 X 1016

Ph t th i 1 X 1014Photosynthesis 1 X 1014

Geothermal flux 3 X 1013

Tides 2 X 1013

Energy use by man (1980) 1 X 1013

UV energy to make O3 layer 1 X 1013

Hydroelectric Power 3 X 1011

Winds 2 X 1011

Volcanoes 4 X 1010

Earthquakes 1 X 1010

Molecules to LifeMolecules to Life

Top of atmosphere

Surface

Top-of-atmosphere

Surface

Top-of-atmosphere

Net DifferencesShortwave

Kiehl and Trenberth 1997

68 100

Observational Dataset

• AIRS (Atmospheric Infrared Sounder)AIRS (Atmospheric Infrared Sounder)Lifetime: May 2002 – PresentSpectral coverage: 650-2665 cm-1Spectral coverage: 650 2665 cmSpectral resolution (FWHM): ν/1200 cm-1

Field of view: 13.5 km(~9 times of the FOVs per AMSU-A FOV)SNR: 600-4000Calibration bias: 0.07-0.5 K in BTOrbit: Sun-synchronous, 1:30 PM sampling

S ath Width: 1650 km t ice dail s athSwath Width: 1650 km, twice daily swath

Absorption in Earth’s Atmosphere

H2O

O3

2

H2O

CO2

Greenhouse gases and radianceGreenhouse gases and radiance

• Outgoing thermal infraredOutgoing thermal infrared spectra (W/m2/cm-1/sr) I(v)– Integrand of OLR, containing g , g

many pieces of useful informationF d l li– Fundamental to climate diagnostics

By courtesy of John Dykema

x: Machida et al. [1995] +: Bernard et al. [2006]

Observational Dataset• IRIS (Infrared Interferometer Spectrometer)

Lifetime: Apr 70 – Jan 71Lifetime: Apr 70 Jan 71 Spectral coverage: 400-1600 cm-1

(in this study, 400-1400 cm-1)Spectral resolution (FWHM): 2.8 cm-1

Field of view: 95km in diameter (~6.25 times of the FOV of ERBE, 15% of an AM2 grid box)SNR: 20~100C lib ti bi 0 25 0 75K i BTCalibration bias: 0.25-0.75K in BTOrbit: Sun-synchronous, 10:30AM/PM sampling

700 000 good spectra over 10 months700,000 good spectra over 10 months

Observational Dataset

• AIRS (Atmospheric Infrared Sounder)AIRS (Atmospheric Infrared Sounder)Lifetime: May 2002 – PresentSpectral coverage: 650-2665 cm-1Spectral coverage: 650 2665 cmSpectral resolution (FWHM): ν/1200 cm-1

Field of view: 13.5 km(~9 times of the FOVs per AMSU-A FOV)SNR: 600-4000Calibration bias: 0.07-0.5 K in BTOrbit: Sun-synchronous, 1:30 PM sampling

S ath Width: 1650 km t ice dail s athSwath Width: 1650 km, twice daily swath

ConclusionsConclusionsConclusionsConclusionsRadiation plays a fundamental role as the Radiation plays a fundamental role as the source of energysource of energy

Spectral radiance provides detailed picture of Spectral radiance provides detailed picture of energy exchangeenergy exchange

Radiation as diagnostic of climate change Radiation as diagnostic of climate change ( t ti l)( t ti l)(potential)(potential)

ThanksThanksThanksThanksYung’s Group at CaltechYung’s Group at CaltechYung s Group at Caltech Yung s Group at Caltech Trenberth (NCAR)Trenberth (NCAR)Prof Xianglei Huang (U Michigan)Prof Xianglei Huang (U Michigan)Prof. Xianglei Huang (U Michigan)Prof. Xianglei Huang (U Michigan)

Ref: Goody and Yung (1989)Ref: Goody and Yung (1989)Huang and Yung (2005) JGR 110Huang and Yung (2005) JGR 110Huang and Yung (2005) JGR 110Huang and Yung (2005) JGR 110

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