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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