ARCTAS BrO Measurements from the OMI and GOME2 Satellite Instruments

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ARCTAS BrO Measurements from the OMI and GOME-2
Satellite Instruments
Kelly Chance, Thomas Kurosu, Trevor Beck, Andreas
Richter, Michel van Roozendael, William Simpson,
Ross Salawitch, Tim Canty, Yuhang Wang

• ARC-IONS Data Workshop
• 7-8 January 2009
• University of Toronto

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Introduction BrO has been measured robustly and
globally from space since the first GOME
measurements in 1998 (Chance, GRL 1998), ,

• Enhanced tropospheric BrO has long been observed
  over the Arctic and Antarctic ice pack in the
  polar spring.

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OMI BrO Tropospheric Shelf Ice
11 March 2005

• BrO is a strong source of O3 destruction in the
  stratosphere and troposphere.
• BrO is measured globally now by SCIAMACHY,
  GOME-2, and OMI

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OMI BrO Tropospheric Salt Lakes 1st Observation
from Satellite
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OMI BrO Volcanoes 1st Observation from Satellite
Ambrym First satellite-based BrO observation in
volcanic plumes!
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GOME/SCIAMACHY/OMI/GOME-2
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Best Fitting
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Fitting satellite BrO

• Requires precise (dynamic) wavelength and slit
  function calibration, Ring effect correction,
  undersampling correction, and proper choices of
  reference spectra (HITRAN!)
• Best trace gas column fitting results come from
  direct fitting of satellite radiances

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GOME BrO fitting for the FIRS-2 overflight on
April 30, 1997. The integration time is 1.5s. The
fitting precision is 4.2 and the RMS is 2.7?10-4
in optical depth. Fitting and inversion give a
vertical BrO column of 9.3?1013 cm-2.
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• Differences among satellites and algorithms are a
  30 or less issue (NB GOME-1).
• Over high albedos, tropospheric and stratospheric
  AMFs differ by about a factor of two.

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Salawitch et al., AGU Fall 2008 ARCTAS ARCPAC
Inorganic Bromine Measurements
? April 2008 deployment from Fairbanks,
Alaska ? Scientific Focus quantification of
the relationship between OMI BrO and the
nearly complete removal of ozone in Arctic
boundary layer Ozone Depletion Events ?
OMI BrO New off line retrieval that fits 320.5
? 356.5 nm region for BrO,
O3, HCHO, SO2, OClO Publicly available
retrieval fits 340.5 ? 358.5 nm region
for BrO, O3, HCHO, SO2, OClO, and
O2-O2 New retrieval low residuals,
much higher signal to noise,
but slight correlation with surface
albedo OMI retrievals by Thomas Kurosu
GOME-2 retrievals by Trevor Beck
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SAO NRT algorithm
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SAO new and improved algorithm
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NOAA/SAO collaboration
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The End!
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ESA Global Ozone Monitoring Experiment

• Nadir-viewing UV/vis/NIR
• 240-400 nm _at_ 0.2 nm
• 400-790 nm _at_ 0.4 nm
• Launched April 1995
• Footprint 320 x 40 km2
• 1030 am cross-equator time,
• descending node
• Global coverage in 3 days

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SCIAMACHY

• German/Dutch/Belgian Atmospheric Spectrometer
• 2002 launch on ESA Envisat
• Adds (to GOME) continuous coverage to 1700 nm,
  plus IR bands at 2.0 ?m (CO2) and 2.4 ?m (CO,
  N2O)
• Higher spatial resolution footprint than GOME (as
  good as 30 ? 60 km2)
• Adds limb scattering and limited solar
  occultation measurements
• Nadir-limb subtraction improves tropospheric
  measurements
• Data and validation are still in a preliminary
  stage

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? 2
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High resolution solar reference spectrum
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GOME BrO fitting Relative contributions
absorption by atmospheric BrO (top) and the Ring
effect - the inelastic, mostly rotational Raman,
part of the Rayleigh scattering (bottom).
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BrO Tropospheric Volcanoes 1st Observation
from Satellite
Ambrym Eruption 4th February 2005, OMI Granule
02968
SO2 courtesy of Simon Carn, UMBC
BrO
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• BrO The Future
• Polar spring BrO/tropospheric O3
• Higher spatial resolution
• Better correlation chemistry (high latitude
  Hg deposition)
• Volcanoes!
• Salt lakes!

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Flight 4 080404 (Fairbanks to Thule)
T. Kurosu, K. Chance, T. Beck, G. Huey, A.
Weinheimer
? DC8 O3
DC8 Alt ?
OMI Column (1013 mol/cm2)
OMI Overpass

DC8 Br2