kathy law service d’aéronomie/ipsl-upmc-cnrs

SPAC meeting, NILU, 5-7 Nov '07

Arctic Ozone Arctic Ozone Possible Reduction StrategiesPossible Reduction Strategies

What can be done given uncertanties in the What can be done given uncertanties in the

(Arctic) O(Arctic) O33 budget and climate change? budget and climate change?

Kathy LawKathy Law Service d’Aéronomie/IPSL-UPMC-CNRSService d’Aéronomie/IPSL-UPMC-CNRS


OutlineOutline OO33 radiative forcing - IR altitude sensitivity radiative forcing - IR altitude sensitivity

OO33 budget (Arctic & NH) - uncertainties - budget (Arctic & NH) - uncertainties - photochemical lifetime vs transport timescalesphotochemical lifetime vs transport timescales

Which emissions? Which emissions? RegionsRegions NOx, CO/VOCs or CH4?NOx, CO/VOCs or CH4?

Response in a changing climate (O3, CH4)Response in a changing climate (O3, CH4)


OO33 radiative radiative forcingforcing

QuickTime™ et undécompresseur TIFF (non compressé)

sont requis pour visionner cette image.

Max effect on Ts from IR heating between 4 - 22 km

Surface ∆O3 lessimportant

From Forster & Shine, 1997


Uncertainties in OUncertainties in O33 RF: RF: Results from IPCC models - GHGs plus strat. O3 (Gauss et al., 2006)Results from IPCC models - GHGs plus strat. O3 (Gauss et al., 2006) Strat. vs trop. model differences (1850 to 2000)Strat. vs trop. model differences (1850 to 2000)







T=trop, S=strat.


Arctic Ozone BudgetArctic Ozone BudgetNorth PoleSTE

UT Transport

LT transport Dry Deposition

Flux outFlux in

Residence Time


Arctic OArctic O33 Budget (TOPSE) Budget (TOPSE)



Emmons et al., 2003


Transport Pathways to ArcticTransport Pathways to ArcticWinter: anthrop. Europe (LT), Asia? (UT)

Summer: forest fires (Siberia, Alaska) anthrop. (Asia, N. America)

AMAP, 2006


Age of Arctic AirAge of Arctic AirQuickTime™ et un

décompresseur TIFF (non compressé)sont requis pour visionner cette image.





Stohl, 2006


Ozone Photochemical Lifetime (days)Ozone Photochemical Lifetime (days)Lifetime - April - Surface

Lifetime - April - 500hPa Lifetime - July - 500hPa

Lifetime - July - Surface

MOZART model results, courtesy Claire Granier (CNRS), NCAR


Northern Hemisphere ONorthern Hemisphere O33 Budget Budget

North Pole

Brewer-Dobson/STELocal heating from local O3

30N

Dry Deposition

Transport of heat ormid-lat O3 to Arctic

30N


Key is UT OKey is UT O33 Budget Budget

North Pole

Brewer-Dobson/STE

Local heating from local O3?

30N

Dry Deposition

Transport of heat ormid-lat O3 to Arctic

30N


Tropospheric OTropospheric O33 - where is the ∆O - where is the ∆O33??


Where is there a constant source of ∆O3? Where is there a constant source of ∆O3? Mid-lat anthrop. plumes transported into UTMid-lat anthrop. plumes transported into UT

•Lagrangian study using NARE-ACSOE data (Real et al., 2007)•Photochemical trajectory model initialised with obs upwind•Determine O3 change due to chemistry, mixing etc.


Intercontinental Transport Of Pollutants

Lagrangian match analysis (Methven et al.,2006), FF analysis (Real et al., 2007)

CO ↓ : 200 ppbv

O3 ↑ : 20 ppbv

DC8 – 18 July

B146 – 20 July

Falcon – 22/23 July

Where is there a constant source of ∆O3? Where is there a constant source of ∆O3? Boreal Forest Fire plumes (ICARTT summer 2004)Boreal Forest Fire plumes (ICARTT summer 2004)

IGAC Lagrangian 2K4 - ITOP campaign, July 2004


Lagrangian photochemical model: chemistry + aerosols + dilution (Real et al., 2007)

NPO3 depends on altitude(PAN decomp. vs H2O) plus mixing & residence time of plumes in UT

OHP Falcon MozaicJungfraujoch

Chemistry only(inc. aerosols)

Chemistry + mixing


Forest Fire Plume - Trace Gas Correlation Evolution

CO (ppbv) CO (ppbv)

CO (ppbv)

O3

(ppb

v)

O3

(ppb

v)

O3

(ppb

v)

DC8 - 18 July 2004 BAe-146 - 20 July 2004

Falcon – 22 et 23 July 2004


Forest Fire Plume Correlation Evolution - evaluation of global models - MOCAGE (Bousserez et al., 2007) and GEOSCHEM (courtesy Isabelle Bey)

140

050

350

100

0 22560

MOCAGE

Observations

GEOS-CHEM75

45100 150

80

18030

90

MOCAGEO3 too high on 18 July

GEOSCHEMCO (PAN) too low on 18 July

O3 too low on 23 July

0 600

200

CO (ppb)

CO (ppb)

O3

(ppb

v)O

3 (p

pbv)

DC8 18 July

DF20 23 July

DC8 18 July

45


Forest Fire Plume Transport to ArcticForest Fire Plume Transport to Arctic(ICARTT 2004)(ICARTT 2004)

Barrow

Alert

80°N

90°N

Stohl, 2006


FF plume transport to the Arctic FF plume transport to the Arctic (Lacresson, (Lacresson, Real, Law, 2007)Real, Law, 2007)

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

2 0 0 2 0 2 2 0 4 2 0 6 2 0 8 2 1 0 2 1 2 2 1 4 2 1 6 2 1 8

J o u r s

Valeurs moyennes d'O3

0

1 0

2 0

3 0

4 0

5 0

6 0

7 0

1 9 5 2 0 0 2 0 5 2 1 0 2 1 5 2 2 0 2 2 5 2 3 0 2 3 5

J o u r s

Valeurs moyennes d'Ozone






sont requis pour visionner cette image.QuickTime™ et un

décompresseur TIFF (non compressé)sont requis pour visionner cette image.

Ny-Alesund

Summit

Ozone - Ny-Alesund (Rao et al, 2004)

8km

6km

2km

Summit @ 3km2004

Ny-Alesundsurface: high O3 episode in July 2004

Ozone Data (Helmig et al, 2007)

Broad summer Max in FT

SPAC meeting, NILU, 5-7 Nov '07 AMAP, 2006

So which regional emissions to reduce?So which regional emissions to reduce?


Uncertainties in Regional EmissionsUncertainties in Regional EmissionsNOx emissions

0

1

2

3

4

5

6

7

8

9

Eur Rus Inde Chine ASE+OC AFR+ME Amer N Amer S

NOx emissions (Tg N/yr)

GICC RETRO MOZART

CO

0

1

2

3

4

5

6

7

8

9

Eur Rus Inde Chine ASE+OC AFR+ME Amer N Amer S

CO Emissions (Tg CO/yr)

GICC RETRO MOZARTCourtesy Claire Granier et al.


Decadal emissions - up to date info is Decadal emissions - up to date info is needed on 1990 to presentneeded on 1990 to present

SO2 emission per large region

0

10

20

30

40

50

60

70

80

Eur Rus Inde Chine ASE+OC AFR+ME Amer_N Amer_S

SO2 emission

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

BC Emissions per large region

00,20,40,60,8

11,21,41,61,8

2

Eur Rus Inde Chine ASE+OC AFR+ME Amer_N Amer_S

BC Emission

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

Courtesy Claire Granier, Cathy Liousse et al.


Regional ORegional O33 changes from reduced emissions (1) changes from reduced emissions (1)



Bernsten et al., 2006


Regional ORegional O33 changes from reduced emissions (2) changes from reduced emissions (2)

Dentener et al., 2005




OO33 RF from BAU (upper) & reduced emissions RF from BAU (upper) & reduced emissions (lower) (lower)

Dentener et al., 2005






Stohl, 2006 - Anthrop BC particle sources 30 days previouslyAir spending at least 5 days in Arctic in winter (left) & summer (right)



Do the same for O3 precursors with some kind of RF clockrelated to residence time in the UT




Stohl, 2006 - BC particle sources 30 days previouslyAir spending at least 5 days in Arctic in summer - forest fires (left) & anthrop (right)






Which Emissions - Which Emissions - CH4CH4, NOx, VOC or CO?, NOx, VOC or CO?

20% emission reductions in CH4, NOx CO & VOCs 20% emission reductions in CH4, NOx CO & VOCs (West, Fiore, et al 2007)(West, Fiore, et al 2007)






CHCH44 emission scenarios (Tg yr-1) - Dentener et al. , 2005 emission scenarios (Tg yr-1) - Dentener et al. , 2005

Net difference BAU - MRF∆CH4ems = 100 Tg (1990 to 2030)


How to reduce CH4?How to reduce CH4?

Law & Nisbet, 1996





Reduction in Gas CH4 by 15 Tg over 3 years led to4 ppbv yr-1 decrease @ 66N


But is CHBut is CH44 already going down? already going down?… and CO… and CO22 going up faster than predicted?? going up faster than predicted??



Hansen et al.,2007


Stratospheric OStratospheric O33 recovery recovery



Eyring et al., 2007


Climate ChangeClimate Change

Possible Impacts on OPossible Impacts on O33 Budget Budget


Climate change effects on strat. & trop. O3Climate change effects on strat. & trop. O3



Gauss et al., 2006


Sensitivity of POSensitivity of PO33 to Temperature to Temperature(PAN decomposition)(PAN decomposition)



Real et al., 2007


More local anthropogenic emissions?More local anthropogenic emissions?• Gas/oil extraction - CHGas/oil extraction - CH44, VOCs (alkanes), BC?, VOCs (alkanes), BC?• Smelters (copper) - SOx, NOx, aerosolSmelters (copper) - SOx, NOx, aerosol• Ships - NOx, aerosolsShips - NOx, aerosols


Loss of summer sea-iceLoss of summer sea-ice more O more O3 3 (ships), less halogens (not (ships), less halogens (not clear), more DMS, etcclear), more DMS, etc

2040

Granier et al, 2006

Holland et al, 2006Are the models right??!!


RecommendationsRecommendations Reduce CHReduce CH44 ( (but need to understand but need to understand current trends and climate sensitivitycurrent trends and climate sensitivity) - ) - plus COplus CO22 also of course also of course

Take into account planned OTake into account planned O33 precursor precursor emission reductions (emission reductions (CLRTAPCLRTAP) & post-) & post-KyotoKyoto

OO33 budget - budget - important where Oimportant where O33 is is formedformed((smoking gun - boreal forest fires?)smoking gun - boreal forest fires?)

kathy law service d’aéronomie/ipsl-upmc-cnrs

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