Global and Seasonal Distributions of CHOCHO and HCHO Observed by the Ozone Monitoring Instrument on

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Global and Seasonal Distributions of CHO-CHO and
HCHO Observed by the Ozone Monitoring Instrument
on EOS Aura
Thomas P. Kurosu, Kelly Chance Harvard-Smithsonian
Center for Astrophysics, Cambridge (MA) Rainer
Volkamer University of California, San Diego
(CA) Tzung-May Fu, Dylan Millet Harvard
University, Cambridge (MA) AGU Fall 2006 San
Francisco 11-15 December
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OMI The Instrument

• Dutch (KNMI) / Finnish (FMI) instrument with US
  (NASA GSFC) collaboration
• PI Pieternel Levelt (KNMI)
• On EOS Aura sun-synchronous, 1338h equator
  crossing time, ascending node
• part of the A Train
• Nadir-viewing CCD spectrometer, 270-500 nm
  spectral range (divided into three channels)
  0.42-0.63 nm spectral resolution
• Daily Global Coverage
• 60 across-track pixels (no scanning!), 2,600 km
  total swath width
• Ground pixel size 1324 km2 at nadir, 40160 km2
  at edges (1313km2 spatial zoom)

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HCHO

• Volatile Organic Compound
• Produced from Methane oxidation, isoprene
  emissions
• Indicator for Air Quality
• Average lifetime 1.5 hrs
• Main sinks Photolysis, reaction with OH

Fitting window 324357 nm (UV2 channel)
Success Story for GOME Large number of science
studies in collaboration with the Harvard
Modeling Group (Paul Palmer, Dylan Millet, Daniel
Jacob) Poised to repeat this with OMI Monthly
and daily HCHO products have emerged Fitting
Uncertainties 50-100
Public Release of Data Initiated!
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CHO-CHO

• Volatile Organic Compound recently observed in
  Mexico City (Volkamer et al., 2005), during
  MILAGRO, and Pearl River Delta
• Produced from oxidation of a large number of
  other, mostly aromatic VOCs
• Unlike HCHO not directly affected by vehicle
  emission, hence a better indicator for VOC
  oxidation (photochemical smog)
• Average loading about 8 of NO2 1.51015 mol/cm2

• Average life-time 1.3 hrs
• Primary sinks Photolysis, reaction with OH

Fitting window 420460 nm (VIS channel)
First reported satellite-based observation from
OMI! Annual, monthly and daily observations
Ground-based Volkamer et al., DOAS measurements
of glyoxal as an indicator for fast VOC chemistry
in urban air, GRL 32, 2005
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CHO-CHO Diurnal Variation
CHO-CHO, HCHO diurnal variation CHOCHO/NO2 ()
ratio
CHO-CHO hour-by-hour peaks between 1030h and
1300h (OMI is at 1338h)
Images taken from Volkamer et al., DOAS
measurements of glyoxal as an indicator for fast
VOC chemistry in urban air, GRL 32, 2005
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OMI Observations of CHO-CHO and HCHOannual,
monthly, and 10-day means
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OMI HCHO and CHO-CHO annual average
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OMI HCHO and CHO-CHO monthly average
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OMI HCHO and CHO-CHO 10-day averages
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OMI HCHO and CHO-CHO Pearl River Delta
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OMI HCHO and CHO-CHO Pearl River Delta
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OMI HCHO and CHO-CHO Pearl River Delta
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OMI HCHO, CHO-CHO, NO2 Proxy Pearl River
Delta, July 2006
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What Do We See From Ground-Based
Measurements?Rainer VolkamerPearl River Delta
2006 Campaign
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Poster A31B-0897
Case Study in the Pearl River Delta,
China Spatial Variability of Glyoxal, HCHO and
NO2 during PRD-2006

• Approach Solar straylight remote sensing from
  ground and space
• Mobile Mini-MAX DOAS (Rainer Volkamer, UCSD)
• OMI Satellite
• Spatial resolution 2 km (ground) 15 km (space)
• Scientific questions
• Satellite validation effort
• Qualitative and quantitative comparisons

Mobile Mini-MAX-DOAS
OMI
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What Do Chemical Models Tell Us?Tzung-May Fu,
Dylan MilletGEOS-Chem simulations for CHO-CHO
and HCHO
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GEOS-Chem Simulations CHO-CHO, HCHO April 2001
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Summary

• OMI on EOS-Aura (global coverage, equator
  crossing time 1338h) is ideally positioned for
  air quality observations.
• HCHO spatial resolution shows great improvements
  over previous GOME results. Recent emergence of
  daily products due to algorithm advancements on
  both L0 -gt L1b and L1b -gt L2 levels processing.
  Publicaly released.
• CHO-CHO data quality is beginning to stabilize.
  Daily observations are well within reach over
  strong source regions like Guangzhou and
  megacities. First continuous record of global
  seasonal observations for a whole year global
  averages on a 10-day temporal resolution.
• Ground-Based Observations in PRD available for
  validation studies.
• GEOS-Chem Simulations (monthly means) available
  for CHO-CHO and HCHO for a 12-month period
  (2001).
• Issues
• OMI monthly means agree well with
  ground-based measurements, but
• individual OMI observations are still not
  stable enough for comparison
• Qualitative comparison with GEOS-Chem
  CHO-CHO is encouraging,
• but only away from regions of biogenic
  hot-spots
• Missing CHO-CHO over isoprene hot-spots -
  possibly an albedo issue in
• the CHO-CHO OMI retrievals or could it
  be something else?

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If we knew what we were doing, it would not be
called research, would it?A. Einstein
(18791955)