distribution of solar radiation

Distribution of Solar RadiationDistribution of Solar Radiation

http://www.atmos.washington.edu/~dennis/Our_Changing_Climate.html

N2

O2

O3

CH4

CO2

H2O

Thesis Topic:Thesis Topic:

Assessing the role of methane as a climate maker, Assessing the role of methane as a climate maker,

using femtosecond laserusing femtosecond laser--induced nonlinear induced nonlinear

spectroscopy for remote sensing of methanespectroscopy for remote sensing of methane..

H

C

HH

H Susan W. Mburu

Penn. MCEP-Cohort 6

August, 10th 2007

Greenhouse GasesGreenhouse Gases

www.epa.gov/nonco2/reports/anthrosummary.html

What Happens When Light Interacts With What Happens When Light Interacts With

Atmospheric Gas Molecules and Particulate Matter?Atmospheric Gas Molecules and Particulate Matter?

The light may be:The light may be:

�� ScatteredScattered

�� Reflected Reflected

�� Transmitted Transmitted

�� AbsorbedAbsorbed

Infrared Absorption of COInfrared Absorption of CO22

www.wunderground.commment.htm...

AAsymmetric stretches

Symmetrical stretches-no absorption

Infrared Absorption of WaterInfrared Absorption of Water

cimss.ssec.wisc.edu/goes/misc/wv/wv_concepts.html

V1=(A1)= 1654cm-1 V3=(A1)= 3936cm-1V2=(A1)= 3828cm-1

Methane vibrationsMethane vibrations

H

CH

H

H

H

CH

H

H

H

CH

H

H

C

H

H

H

H

CH H

H

H

C

H

H

H

symmetric stretch

asymmetric stretch

scissoring wagging

rocking twisting

H

Properties of Methane

� Belongs to Td point group

� Spherical top

� has nine vibrational degrees of freedom

Normal mode frequencies

� A: 2885 cm-1

� E: 1501cm-1

� T2: 3052cm-1

� T2: 1339 cm-1

Methane's IR Spectral SignatureMethane's IR Spectral Signature

3000cm-1 1400cm-1

Stretching Bending

Greenhouse Gases Absorb Specific WavelengthsGreenhouse Gases Absorb Specific Wavelengths

www.geology.iastate.edu/.../forcing/images.html

Greenland Ice Cores Provide information about COGreenland Ice Cores Provide information about CO22

& CH& CH44 Concentrations and Temperature ChangesConcentrations and Temperature Changes……

www.berkeley.edu/.../2005/12/14_methane.shtml

Bottom

Top

Greenland Ice Core FindingsGreenland Ice Core Findings……

www.grida.no/climate/ipcc_tar/wg1/figspm-2.htm

Global TemperatureGlobal Temperature

http://www.globalwarmingart.com/wiki/Image:Instrumental_Temperature_Record.png

Natural Sources of MethaneNatural Sources of Methane

Anthropogenic Sources of MethaneAnthropogenic Sources of Methane

Comparing Natural and Comparing Natural and

Anthropogenic Sources of MethaneAnthropogenic Sources of Methane

Methane Sources and SinksMethane Sources and Sinks

�� Methane is produce by methanotropic bacteria in anaerobic Methane is produce by methanotropic bacteria in anaerobic environmentsenvironments

CC66HH1212OO66→→ 3CO3CO22 + 3CH+ 3CH44

Methane is removed from the environment as shownMethane is removed from the environment as shown……

�� CHCH4 4 + OH + OH ..→→ CHCH33.. + + HH22OO

�� OO33 + hv + hv →→OO22 + O + O ..

�� CHCH44 + 2O+ 2O22→→ COCO2 2 + 2H+ 2H22O O

�� CHCH4 4 + Cl+ Cl..→→ HCl + HCl + CHCH33..

�� More More methane is produced than is removed leading to 1% annual methane is produced than is removed leading to 1% annual increase in accumulation increase in accumulation

�� Methane has a positive feedback on the greenhouse effectMethane has a positive feedback on the greenhouse effect

�� Methane has a lifetime of about 10 years in the atmosphereMethane has a lifetime of about 10 years in the atmosphere

Techniques Used for Monitoring the Techniques Used for Monitoring the

Concentration of Atmospheric GasesConcentration of Atmospheric Gases

Conventional techniques:Conventional techniques:

�� Balloon and aircraftBalloon and aircraft-- borne instruments e.g. GC/MS borne instruments e.g. GC/MS (expensive)(expensive)

Laser techniques:Laser techniques:

�� Differential optical absorption spectroscopy (DOAS)Differential optical absorption spectroscopy (DOAS)

�� Tunable diode laser infrared spectroscopy (TDLAS)Tunable diode laser infrared spectroscopy (TDLAS)

�� The laser techniques offer good analytical results and The laser techniques offer good analytical results and can remotely provide realcan remotely provide real--time online sensing of time online sensing of atmospheric gases. However the lasers may only be atmospheric gases. However the lasers may only be optimized for one gas at a time.optimized for one gas at a time.

The Ideal Instrument for Investigating The Ideal Instrument for Investigating

Atmospheric Gases Should have..Atmospheric Gases Should have..

In order to understand the dynamic chemical processes affectingIn order to understand the dynamic chemical processes affecting

global warming , atmospheric pollution and ozone depletion global warming , atmospheric pollution and ozone depletion

the technique should have the following features:the technique should have the following features:

�� laser based technology laser based technology

�� High sensitivity (High sensitivity (ppmppm, ppb, , ppb, pptppt))

�� High selectivityHigh selectivity

�� Remote capabilitiesRemote capabilities

�� Allow for measurement of a variety of targets simultaneouslyAllow for measurement of a variety of targets simultaneously

�� Provide realProvide real-- time intime in--situ measurementssitu measurements

�� Long rangeLong range

The Femtosecond LaserThe Femtosecond Laser--Induced Induced

Nonlinear SpectroscopyNonlinear Spectroscopy

Ti :sapphire

oscillator

Experimental set up:

Source: Q.Luo, Remote sensing of pollutants using femtosecond laser pulse fluorescence

spectroscopy. App.. Phys 2006, 105-107.

The Femtosecond laser PulseThe Femtosecond laser Pulse

www.mpipks-dresden.mpg.de/.../research.html

1 2 3 4

Laser is

compressed

And chirped

800nm,200ps 45fs

5

Balance Between Kerr Self Focusing and Balance Between Kerr Self Focusing and

Plasma DefocusingPlasma Defocusing


Laser Low density plasma

Spectral broadening (300nm-4.5µm)

White light

In A positively chirped waveforms..In A positively chirped waveforms..

The frequency is increasing with time


A linearly chirped waveform An exponentially chirped waveform

The Interact Between the White Laser The Interact Between the White Laser

Filament and Gas Molecules Causes..Filament and Gas Molecules Causes..

�� IonizationIonization

�� FragmentationFragmentation

�� Excitation and emission of characteristic Excitation and emission of characteristic fluorescence fluorescence

�� The whiteThe white--light laser possesses directional light laser possesses directional properties which enhance backward scatteringproperties which enhance backward scattering

�� Absorption of the white light Absorption of the white light

The spectra obtained from all the above processes The spectra obtained from all the above processes provides information about the gases presentprovides information about the gases present

Spectra of Pure Methane (Control)Spectra of Pure Methane (Control)

Source: Q.Luo, Remote sensing of pollutants using femtosecond laser pulse fluorescence

spectroscopy. Appl. Phys 2006, 105-107.

Experimental Results

Spectra of AirSpectra of AirExperimental Results

Source: Q.Luo, Remote sensing of pollutants using femtosecond laser pulse

fluorescence spectroscopy. Appl. Phys 2006, 105-107

Spectra of Methane and Air MixtureSpectra of Methane and Air Mixture

Inserts (1) &(2)

Show higher resolutionsSource: Q.Luo, Remote sensing of pollutants using femtosecond

laser pulse fluorescence spectroscopy. Appl. Phys 2006, 105-107

Spectrum of air gas mixture after Spectrum of air gas mixture after

subtracting the air backgroundsubtracting the air background

The spectrum is the same as the control

Source: Q.Luo, Remote sensing of pollutants using femtosecond

laser pulse fluorescence spectroscopy. Appl. Phys 2006, 105-107.

Intensity of Spectral Lines Vs ConcentrationIntensity of Spectral Lines Vs Concentration

Source: Q.Luo, Remote sensing of pollutants using femtosecond laser

pulse fluorescence spectroscopy. Appl. Phys 2006, 105-107.

Schematic Diagram of the Femtosecond Laser Schematic Diagram of the Femtosecond Laser

Spectroscope Spectroscope --Field Setup (Teramobile)Field Setup (Teramobile)

www.gap.unige.ch/biophotonics/research3.htm

White light Supercontinuum Produced in the White light Supercontinuum Produced in the

Atmosphere by the Femtosecond laser Atmosphere by the Femtosecond laser


The White laser light is used to analyze the atmospheric gases and particles

Remote Sensing and RangingRemote Sensing and Ranging

Use BackUse Back--Scattered RadiationScattered Radiation

Backward Scatter Spectrum of AirBackward Scatter Spectrum of Air


A variety of molecules and other particles can be detected at the same time

Applications of Remote Sensing of the Applications of Remote Sensing of the

AtmosphereAtmosphere

�� Analysis of the concentration of gaseous speciesAnalysis of the concentration of gaseous species

�� Diagnosis of Aerosol distribution and optical propertiesDiagnosis of Aerosol distribution and optical properties

�� Detecting biomoleculesDetecting biomolecules

�� Measurement of cloud heightMeasurement of cloud height

�� Weather predictionsWeather predictions

�� Lightning detection and controlLightning detection and control

Future ImprovementsFuture Improvements……

�� Better results expected in future with the Better results expected in future with the

development of ultra fast laser technologydevelopment of ultra fast laser technology

�� Miniaturization Miniaturization –– nanotechnologynanotechnology

�� Higher sensitivityHigher sensitivity

�� Greater detection limitsGreater detection limits

�� Development of a twoDevelopment of a two--dimensional beam profiledimensional beam profile

�� Development of pulse shaping techniquesDevelopment of pulse shaping techniques

ConclusionConclusion

�� Methane is a powerful greenhouse gas which has Methane is a powerful greenhouse gas which has

a positive feedback effect on global warming. a positive feedback effect on global warming.

Reducing its emissions could be the most cost Reducing its emissions could be the most cost

effective way of reducing global warming effective way of reducing global warming

quickly. quickly.

ReferencesReferences1.1. Gavin, S., Methane: A scientific journey from obscurity to climaGavin, S., Methane: A scientific journey from obscurity to climate superte super--stardom. stardom. NasaNasa Goddard institute for space studies Goddard institute for space studies 20042004..

2.2. Sloan, E. D., 1998. Sloan, E. D., 1998. clathrate Hydrates of Natural Gasclathrate Hydrates of Natural Gas..

3.3. Jeffrey, G. A., Inclusion Compounds. Jeffrey, G. A., Inclusion Compounds. 19841984..

4.4. NangiaNangia, A., Organic host, A., Organic host--guest structure in the solid state. guest structure in the solid state. 20042004..

5.5. Kim DOKim DO--YounYoun, P. Y., Lee , P. Y., Lee HuenHuen, Tuning clathrates hydrates: Application to hydrogen storage. , Tuning clathrates hydrates: Application to hydrogen storage. Science direct Science direct 20062006..

6.6. BoudonBoudon, V., Spectroscopic tools for remote sensing of greenhouse gases, V., Spectroscopic tools for remote sensing of greenhouse gases CH4,CF4 and SF6. CH4,CF4 and SF6. Environ Chem Environ Chem LettLett 20032003..

7.7. W.BogueW.Bogue, R., Remote gas detection using ambient thermal infrared. , R., Remote gas detection using ambient thermal infrared. Emerald Emerald 2003,2003, 23, (1), 2623, (1), 26--29.29.

8.8. HodgkinsonHodgkinson, J.; van Well, B.; Padgett, M.; Pride, R. D., , J.; van Well, B.; Padgett, M.; Pride, R. D., ModellingModelling and interpretation of gas detection using remote laser pointersand interpretation of gas detection using remote laser pointers. . SpectrochimicaSpectrochimica ActaActa Part aPart a--Molecular and Molecular and BiomolecularBiomolecular Spectroscopy Spectroscopy 2006,2006, 63, (5), 92963, (5), 929--939.939.

9.9. Chan, K.; Ito, H.; Chan, K.; Ito, H.; InabaInaba, H., An Optical, H., An Optical--FiberFiber--Based Gas Sensor for Remote Absorption Measurement of LowBased Gas Sensor for Remote Absorption Measurement of Low--Level Ch4 Gas in Level Ch4 Gas in the nearthe near--Infrared Region. Infrared Region. Journal of Journal of LightwaveLightwave Technology Technology 1984,1984, 2, (3), 2342, (3), 234--237.237.

10.10. Roland, H., Remote Detection of Methane by Infrared SpectrometryRoland, H., Remote Detection of Methane by Infrared Spectrometry for Airborne Pipeline for Airborne Pipeline SurrveillanceSurrveillance: First Results of Ground: First Results of Ground--Based Measurements. Based Measurements. Remote Sensing of Clouds and the Atmosphere Remote Sensing of Clouds and the Atmosphere 2004,2004, 5235.5235.

11.11. H.L, X.; Daigle, J. F.; H.L, X.; Daigle, J. F.; Q.LuoQ.Luo; Chin, S. L., Femtosecond laser; Chin, S. L., Femtosecond laser--induced nonlinear spectroscopy for remote sensing of methane. induced nonlinear spectroscopy for remote sensing of methane. Applied Applied physics B physics B 20052005..

12.12. KasparianKasparian, J.; Rodriguez, M.; , J.; Rodriguez, M.; MejeanMejean, G.; Yu, J.; Salmon, E.; , G.; Yu, J.; Salmon, E.; WilleWille, H.; , H.; BourayouBourayou, R.; Frey, S.; Andre, Y. B.; , R.; Frey, S.; Andre, Y. B.; MysyrowiczMysyrowicz, A.; , A.; SauerbreySauerbrey, R.; Wolf, J. P.; , R.; Wolf, J. P.; WosteWoste, L., White, L., White--light filaments for atmospheric analysis. light filaments for atmospheric analysis. Science Science 2003,2003, 301, (5629), 61301, (5629), 61--64.64.

13.13. BejotBejot, P., , P., BonacinaBonacina, L., , L., Extermann,JExtermann,J., et al, 32Tw atmospheric white., et al, 32Tw atmospheric white--light laser. light laser. Applied physics Applied physics 2007,2007, 90, (15).90, (15).

14.14. Gravel, J. F.; Gravel, J. F.; LuoLuo, Q.; Boudreau, D.; Tang, X. P.; Chin, S. L., Sensing of halocar, Q.; Boudreau, D.; Tang, X. P.; Chin, S. L., Sensing of halocarbons using femtosecond laserbons using femtosecond laser--induced fluorescence. induced fluorescence. Analytical Chemistry Analytical Chemistry 2004,2004, 76, (16), 479976, (16), 4799--4805.4805.

15.15. mejeanmejean, G., , G., KasparianKasparian, J., Yu, J., et al, UV, J., Yu, J., et al, UV--supercontinuumsupercontinuum generated by femtosecond pulse generated by femtosecond pulse filamentationfilamentation in air. in air. ApplAppl. Phys . Phys 2006,2006, 82.82.

16.16. Q.LuoQ.Luo, Remote sensing of pollutants using femtosecond laser pulse flu, Remote sensing of pollutants using femtosecond laser pulse fluorescence spectroscopy. orescence spectroscopy. ApplAppl. Phys . Phys 20062006, 105, 105--107.107.

17.17. XuXu, H. L.; Daigle, J. F.; , H. L.; Daigle, J. F.; LuoLuo, Q.; Chin, S. L., Femtosecond laser, Q.; Chin, S. L., Femtosecond laser--induced nonlinear spectroscopy for remote sensing of methane. induced nonlinear spectroscopy for remote sensing of methane. Applied Physics BApplied Physics B--Lasers and Optics Lasers and Optics 2006,2006, 82, (4), 65582, (4), 655--658.658.

18.18. SvanbergSvanberg, S., In air monitoring by spectroscopic techniques. , S., In air monitoring by spectroscopic techniques. 19941994..

AcknowledgementsAcknowledgements

�� Dr. Andrew RappeDr. Andrew Rappe-- Thesis Supervisor Thesis Supervisor

�� Megan Cubbage Megan Cubbage -- TATA

�� Members of Cohort 6Members of Cohort 6

distribution of solar radiation

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