ANALYSIS OF TROPOSPHERIC OBSERVATIONS ANALYSIS OF TROPOSPHERIC OBSERVATIONS FROM GOME AND TOMSFROM GOME AND TOMS

Randall Martin, Daniel Jacob,Jennifer Logan, Paul Palmer

Harvard University Kelly Chance, Thomas Kurosu

Harvard-Smithsonian Center for Astrophysics

HOW DO COLUMNS OF TROPOSPHERIC NOHOW DO COLUMNS OF TROPOSPHERIC NO22 FROM FROM

GOME COMPARE WITH TRADITIONAL BOTTOM-UP NOGOME COMPARE WITH TRADITIONAL BOTTOM-UP NOxx

INVENTORIES? INVENTORIES?

Emission

NOh (440 nm)

O3, RO2

NO2

HNO3

NOx lifetime 1 day

NITROGEN OXIDES (NOx)

BOUNDARYLAYER

~ 2 km

Tropospheric NO2 column ~ ENOx

Deposition

GOME/SCIAMACHY

NO/NO2 WITH ALTITUDE

RETRIEVAL OF TROPOSPHERIC NORETRIEVAL OF TROPOSPHERIC NO2 2 FROM GOME FROM GOME (errors (errors in 10in 101515 molecules cm molecules cm-2-2))

GOME SPECTRUM (423-451 nm)

SLANT NO2 COLUMN

TROPOSPHERIC SLANT NO2 COLUMN

TROPOSPHERIC NO2 COLUMN

Fit spectrum

Remove stratospheric contribution, diffuser plate artifact

Use Central Pacific GOME data with:•HALOE to test strat zonal invariance•PEM-Tropics, GEOS-CHEM 3-D model to treat tropospheric residual

Apply AMF to convert slant column to vertical column

Use radiative transfer model with:•local surface albedos from GOME •local vertical shape factors from GEOS-CHEM global model• local cloud info from GOMECAT

O3, O4, H2O, Ring, Undersampling, Common Mode

Quantitative retrieval in partly cloudy scene

GEOS-CHEM MODELGEOS-CHEM MODEL• Assimilated Meteorology (GEOS)• 2ox2.5o (4ox5o) horizontal resolution, 26 layers in vertical

• 24 tracers, 120 solved species, ~400 reactions describe tropospheric O3-NOx-hydrocarbon chemistry

• Heterogeneous chemistry (with off-line aerosol fields)• Photolysis: Fast-J including aerosol scattering • Emissions:

– Fossil fuel: GEIA (NOx), Logan (CO), Piccot (NMHCs)

– Biosphere: modified GEIA (hydrocarbons) & Yienger/Levy (soil NOx)

– Lightning: Price/Rind/Pickering, GEOS convective cloud tops – Interannually varying biomass burning (Logan, Duncan et al. 2002)

• Deposition: modified Wesely (dry), Liu/Mari (wet)• Cross-tropopause transport: SYNOZ

RECENT AND CURRENT APPLICATIONS:• Tropospheric ozone : global budget, Asian outflow, U.S. air quality, Middle East, transatlantic

transport, tropics (TOMS) • Carbon monoxide: budgets, interannual variability• Studies of Aerosols, Carbon dioxide, and Organics• Satellite retrievals, inversions, data assimilation: CO, CO2, O3, HCHO, NO2• Chemical forecasting: TRACE-P, NOAA 2K2

GEOS-CHEM MODEL CAPTURES REGIONAL GEOS-CHEM MODEL CAPTURES REGIONAL VARIATION IN NOVARIATION IN NO

GEOS-CHEM

Aircraft Observations

NO2 number density

RETRIEVAL OF TROPOSPHERIC NORETRIEVAL OF TROPOSPHERIC NO2 2 FROM GOME FROM GOME

GOME SPECTRUM (423-451 nm)

SLANT NO2 COLUMN

TROPOSPHERIC SLANT NO2 COLUMN

TROPOSPHERIC NO2 COLUMN

Remove stratospheric contribution, diffuser plate artifact

Use Central Pacific GOME data with:•HALOE to test strat zonal invariance•PEM-Tropics, GEOS-CHEM 3-D model to treat tropospheric residual

GEOS-CHEM MODEL IDENTIFIES FAVORABLE REGIONS TO DETERMINE STRATOSPHERIC COLUMN

BIAS THAT WOULD RESULT FROM THE ASSUMPTION OF ZERO TROPOSPHERIC NO2 OVER THE PACIFIC

Comparison with PEM-T observations of NO from aircraft suggests small model bias

GEOS-CHEM

Aircraft Observations

NO2 number density

TROPOSPHERIC NOTROPOSPHERIC NO22 COLUMN FROM GOME AFTER COLUMN FROM GOME AFTER

REMOVING STRATOSPHERE AND DIFFUSER PLATE REMOVING STRATOSPHERE AND DIFFUSER PLATE ARTIFACT, AND CORRECTING FOR THE PACIFIC BIASARTIFACT, AND CORRECTING FOR THE PACIFIC BIAS

1996

RETRIEVAL OF TROPOSPHERIC NORETRIEVAL OF TROPOSPHERIC NO2 2 FROM GOME FROM GOME

GOME SPECTRUM (423-451 nm)

SLANT NO2 COLUMN

TROPOSPHERIC SLANT NO2 COLUMN

TROPOSPHERIC NO2 COLUMN

Apply AMF to convert slant column to vertical column

Use radiative transfer model with:•local surface albedos from GOME •local vertical shape factors from GEOS-CHEM global model• local cloud info from GOMECAT

Quantitative retrieval in partly cloudy scene

IN SCATTERING ATMOSPHERE, AMF CALCULATIONIN SCATTERING ATMOSPHERE, AMF CALCULATIONNEEDS EXTERNAL INFO ON SHAPE OF VERTICAL PROFILENEEDS EXTERNAL INFO ON SHAPE OF VERTICAL PROFILE

d()

IoIB

EARTH SURFACE

RADIATIVE TRANSFER MODEL

Scattering weight

B

e

I1w

ln)(

AMF)(

G

ATMOSPHERIC CHEMISTRY MODEL

“a-priori” Shape factor

22

NONO )()(

airCS

1

T

dSw )()(AMFvertical

slantAMF G

Tabulate w() as function of:• solar and viewing zenith angle• surface albedo, pressure• cloud optical depth, pressure

INDIVIDUALGOME SCENES

NO2 mixing ratio CNO2()

() is temperature dependent cross-section

sig

ma

()

CLOUDS SIGNIFICANTLY AFFECT SENSITIVITY OF GOME

Clear-sky scattering weights

Cloudy-sky scattering weights

Shape factor

CLOUD REFLECTIVITY (Rc) AND CLOUD FRACTION (f) HAVE A LARGE INFLUENCE ON THE AMF

Solar Zenith Angle Cloud Optical Thickness

fRf1R

fRf1R

ca

ccaa

)(

AMF)(AMFAMF

Clear-sky AMF

Fraction of I From Clouds (GOMECAT and LIDORT)

Actual AMF accounting for clouds

JULY 1996

VERTICAL COLUMNS LARGELY CONFINED TO VERTICAL COLUMNS LARGELY CONFINED TO REGIONS OF SURFACE EMISSIONSREGIONS OF SURFACE EMISSIONS

NO/NO2

WITH ALTITUDE

NOx lifetime ~1day

GOME RETRIEVAL OF TROPOSPHERIC NOGOME RETRIEVAL OF TROPOSPHERIC NO22

vs. GEOS-CHEM SIMULATION (July 1996)vs. GEOS-CHEM SIMULATION (July 1996)

GEIA & Loganemissionsscaled to 1996

MODELS AND SATELLITE OBSERVATIONS: MODELS AND SATELLITE OBSERVATIONS: THE ODD COUPLETHE ODD COUPLE

SATELLITE SPECTRA“L1 DATA”

ATMOSPHERIC CONCENTRATIONS

“L2 DATA”

RETRIEVALA PRIORI INFORMATIONprofile shape,

Concentration range,Correlations…

SCIENTIFIC ANALYSIS“L4 DATA”

IN SITU OBSERVATIONS(“L1 DATA”)

MODELS

EVALUATIONASSIMILATION

INCREASEDKNOWELDGE

INCEST?

DIAGNOSE MODEL CONTAMINATION OF RETRIEVAL DIAGNOSE MODEL CONTAMINATION OF RETRIEVAL BY CORRELATING AMF WITH VERTICAL COLUMNBY CORRELATING AMF WITH VERTICAL COLUMN

r = -0.14

r = -0.65

Negative correlation implies that AMF conversion to vertical columns will modify the slant column patterns to better fit the model

Little relationship between AMF and enhanced NO2 columns

CAN WE USE GOME TO ESTIMATE NOCAN WE USE GOME TO ESTIMATE NOx x EMISSIONS?EMISSIONS?TEST IN U.S. WHERE GOOD TEST IN U.S. WHERE GOOD A PRIORI A PRIORI EXISTS EXISTS

Comparison of GOME retrieval (July 1996) to GEOS-CHEM model fieldsusing EPA emission inventory for NOx

GOME

GEOS-CHEM(EPA emissions) GOME

BIAS = +18%

R = 0.78

NONO22 COLUMN FROM LIGHTNING SMALL COMPARED COLUMN FROM LIGHTNING SMALL COMPARED

TO RETRIEVAL ERRORTO RETRIEVAL ERROR

Error in Tropospheric NO2 Column Retrieval 7-33x1014 molecules cm-2

Tropospheric NO2 Column Enhancement from Lightning (6 Tg N yr-1) for July (GEOS-CHEM)

We conclude that GOME is consistent with bottom-up NOWe conclude that GOME is consistent with bottom-up NOxx

emissions inventories, but interesting differences remain …emissions inventories, but interesting differences remain …

?

?

?

Fires Biosphere Humanactivity

Lightning

Ocean

Nitrogen oxides (NOx) CO, Hydrocarbons

hOzone (O3)

h, H2OHydroxyl (OH)

What can we learn from TOMS about the relative roles of biomass burning, lightning, and dynamics in the distribution of tropical tropospheric ozone?

TROPICAL TROPOSPHERIC OZONE LARGELY DETERMINES

OXIDIZING POWER OF ATMOSPHERE

MOST LIGHTNING ACTIVITY IS OVER LAND

INTENSE BIOMASS BURNING OVER NORTHERN AFRICA DURING DJF

TROPOSPHERIC OZONE COLUMNS (Sep’96-Aug’97)TROPOSPHERIC OZONE COLUMNS (Sep’96-Aug’97)

GEOS-CHEM TOMS (CCD)

JJA

SON

MAM

DJF

R = 0.66MODEL BIAS = -0.5 DU

EL NINO INTERANNUAL VARIABILITY IN OZONE:EL NINO INTERANNUAL VARIABILITY IN OZONE:DIFFERENCE BETWEEN OCT 97 AND OCT 96DIFFERENCE BETWEEN OCT 97 AND OCT 96

Chandra et al. [2002]

OZONE ENHANCEMENT FROM LIGHTNING (GEOS-CHEM)OZONE ENHANCEMENT FROM LIGHTNING (GEOS-CHEM) largely explains observed wave-1 pattern in TOMS ozone largely explains observed wave-1 pattern in TOMS ozone

SIMULATED OZONE CONCENTRATIONS AND FLUXESSIMULATED OZONE CONCENTRATIONS AND FLUXESAT 300 hPa IN JAN 97AT 300 hPa IN JAN 97

Incursion of northern hemispheric ozone over the South Atlanticthrough the “westerly duct” contributes to the wave-1 pattern

OZONE VERTICAL PROFILES OVER ABIDJANOZONE VERTICAL PROFILES OVER ABIDJAN

North African Dec-Feb ozone enhancement from biomass burning Is seen by aircraft observations but not by TOMS

MOZAICaircraftdata

GEOS-CHEM

TOMS(distributed w/assumed standard profile)

RAYLEIGH SCATTERING LIMITS SENSITIVITY OF TOMS TO RAYLEIGH SCATTERING LIMITS SENSITIVITY OF TOMS TO SEASONAL VARIATION IN LOWER TROPOSPHERESEASONAL VARIATION IN LOWER TROPOSPHERE

TOMS sensitivity to ozone(LIDORT radiativetransfer model)

TOMS standard profiles

S. Atlanticprofile

Abidjan profile

TOMS UNDERESTIMATES OZONE OVER BIOMASS BURNING REGIONS AND OVERESTIMATES OZONE

OVER THE PACIFIC

CORRECTION FOR TOMS RETRIEVAL EFFICIENCY CORRECTION FOR TOMS RETRIEVAL EFFICIENCY CANNOT EXPLAIN DISCREPANCY OVER ABIDJAN CANNOT EXPLAIN DISCREPANCY OVER ABIDJAN

What do GOME and SCIAMACHY observe?What do GOME and SCIAMACHY observe?

TOMS (CCD)

Corrected CCD

TOMS (MR)

GEOS-CHEM

Tropopause

200 hPa

MOZAIC(200 hPa)

Month

SUMMARYSUMMARY

WAVE-1 from Lightning

What does GOME show?

Surface NOx from GOME

Accurate a-priori vertical profile and cloud info

essential for nadir retrievals