A model study on satellite A model study on satellite observed tropical observed tropical

tropospheric ozone tropospheric ozone columnscolumns

Model results and satellite Model results and satellite observations: How can we observations: How can we optimally confront them?optimally confront them?

W. Peters, M.C. Krol, F.J. Dentener, A.M. Thompson and J. Lelieveld

Message:Message:

A A quantitativequantitative approach is necessary. approach is necessary. This requires a careful evaluation of This requires a careful evaluation of

modeling strategiesmodeling strategies..

Satellite observations:Satellite observations:

1979-1992 Modified-Residual TTOC (2x1, monthly mean)1979-1992 Modified-Residual TTOC (2x1, monthly mean)

ModelModel1979-1993 off-line meteo (ECMWF) (5x4, monthly mean)1979-1993 off-line meteo (ECMWF) (5x4, monthly mean)

Atlantic ~40 DU

Atlantic ~60 DUPacific ~15 DU

Pacific ~15 DU Pacific ~15 DU

Pacific ~15 DU

Zonal wave one (zwo): Zonal wave one (zwo): Pacific fit, Pacific fit, Atlantic mismatchAtlantic mismatch

QuantitativeQuantitative measure of error: measure of error:

11 = correlation{zwo= correlation{zwotm3tm3,zwo,zwoobsobs}}

22 = RMS {zwo= RMS {zwotm3tm3,zwo,zwoobsobs} / } / obsobs

latit. avg. (Sept ‘92)

Observations+Model

Quantify discrepancies: Quantify discrepancies: 22

l.

tim

e

Atl. Atl.Pac. Pac. Pac. Pac.

Sensitivities and PrioritiesSensitivities and Priorities

• Biomass burning injection heightBiomass burning injection height• Biomass burning fire calendarBiomass burning fire calendar• Lightning NOx emission yearly totalLightning NOx emission yearly total• Lightning NOx emissions distributionLightning NOx emissions distribution• Biomass burning emission factors (NOx)Biomass burning emission factors (NOx)• Lightning NOx emission profilesLightning NOx emission profiles• ……• ……

Sensitivities and PrioritiesSensitivities and Priorities

Base run:Base run:

1992 meteo1992 meteo

1992 emissions1992 emissions

1992 MR-TTOC1992 MR-TTOC

Pacific = 90E to 90WPacific = 90E to 90W

Atlantic = 90W to 90EAtlantic = 90W to 90E0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

e1 e2 (Pac) e2 (Atl)

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

e1 e2 (Pac) e2 (Atl)

Threshold for better than 10% random 2 = 0.01

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

e1 e2 (Pac) e2 (Atl)

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

e1 e2 (Pac) e2 (Atl)0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

e1 e2 (Pac) e2 (Atl)

2x NOxfrom biomass

burning

2x J(HNO3)in free

troposphere

New firecalendar from

fire counts

5 DU reduction of observations

Recommendations:Recommendations:

Quantify results (despite uncertainties)Quantify results (despite uncertainties) Tailor strategies:Tailor strategies:

Interact with satellite retrieval communityInteract with satellite retrieval community Anticipate ongoing retrieval developments Anticipate ongoing retrieval developments

Peters et. al. (2002), Chemistry-transport modeling of the satellite observed distribution of tropical tropospheric ozone, Atm. Chem. Phys. Vol 2, p 103-120.

http://www.copernicus.org/EGS/acp

ResultsResults Quantification of transport influenceQuantification of transport influence Priority list for model improvementsPriority list for model improvements Detailed list of model sensitivitiesDetailed list of model sensitivities Suggested improvements in MR-retrievalSuggested improvements in MR-retrieval Insights in feasibility of inversionsInsights in feasibility of inversions Experience in model-satellite combinationExperience in model-satellite combination

Sensitivities and DirectionsSensitivities and Directions

Lightning param.Lightning param.

Land/Ocean ratioLand/Ocean ratio

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

2

e1 e2 (Pac) e2 (Atl)

Sensitivities and DirectionsSensitivities and Directions

Biomass burningBiomass burning

Double HNO3 photolysisDouble HNO3 photolysis

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

e1 e2 (Pac) e2 (Atl)

Threshold for better than 10% random 2 = 0.01

Sensitivities and DirectionsSensitivities and Directions

Biomass burningBiomass burning

New fire calendarNew fire calendar

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

e1 e2 (Pac) e2 (Atl)

Threshold for better than 10% random 2 = 0.01

Sensitivities and DirectionsSensitivities and Directions

Lightning param.Lightning param.

Double NOxDouble NOx

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

e1 e2 (Pac) e2 (Atl)

mid-latitudes

Threshold for better than 10% random 2 = 0.01

Sensitivities and DirectionsSensitivities and Directions

Satellite dataSatellite data

5 DU reduction5 DU reduction

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6

1,8

e1 e2 (Pac) e2 (Atl)

Threshold for better than 10% random 2 = 0.01

Sensitivities / DirectionsSensitivities / Directions

Threshold for better than 10% random 2 = 0.01

Importance of transportImportance of transport

Actual yearAverage

El Niño

Threshold for better than 10% random= 0.001