Aerosol optical properties measured from aircraft, satellites and the ground during ARCTAS - their relationship to CCN, aerosol chemistry and smoke type

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Aerosol optical properties measured from
aircraft, satellites and the ground during ARCTAS
- their relationship to CCN, aerosol chemistry
and smoke type

• Yohei Shinozuka, John Livingston, Jens Redemann,
  Phil Russell, Roy Johnson, S Ramachandran (NASA
  Ames),
• Tony Clarke, Cameron McNaughton, Steffen Freitag,
  Steve Howell, Volodia Kapustin, Vera Brekhovskikh
  (University of Hawaii),
• Terry Lathem, Thanos Nenes (Georgia Tech)
• Brent Holben, Norm O'Neill, Bruce McArthur and
  Alain Royer (AERONET)
• yohei_at_hawaii.edu

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In this talk

• Consistency check among the P-3 aircraft, ground
  and satellite observations of spectral aerosol
  optical depth (AOD)
• Linking CCN and optical properties
• Optical characterization of aerosol composition
  and smoke type

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Consistency check
AATS-14
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AOD above P-3 (measured with AATS-14) 0.033
An example of extinction profile See also HSRL
talk.
PRELIMINARY DATA Clarke, McNaughton, Freitag,
Howell et al.
Layer AOD over aircraft altitudes (500 6250 m
GPS) 0.201 at 550 nm
AOD below P-3 0.005 (150 m 30.5 Mm-1)
500
350 (Surface)
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HiGEAR layer AOD was typically within 10 0.02
of the AATSs for the 35 spiral vertical profiles
with altitude gain/loss greater than 1 km under
clear sky with AATS and HiGEAR instruments
running.
PRELIMINARY
10 0.02 11 agreement -10 - 0.02
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Camsell Viking fires north of Lake Athabasca
Time 192.8937
Marker size proportional to dry scattering
HiGEAR Dry Scattering 4000 Mm-1 at 550 nm, AATS
AOD 2.5 at 519 nm in the smoke. The high
spatial variability prevented agreement between
AATS and HiGEAR.
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P-3 and AERONET AODs
Fort McMurray
P-3
AERONET
AERONET PIs Holben, O'Neill, McArthur and Royer
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PEARL at Eureka
P-3 and AERONET AODs agreed within lt0.01
(excellent!) 0.02 (good) during 3 fly-over
events, at all wavelengths but 1.6 um.
AERONET PIs Holben, O'Neill, McArthur and Royer
Fort McMurray
Saturn Island off Vancouver
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Comparison of AATS with Satellites (OMI and MODIS)
MODIS, OMI
AOD (380 nm)
OMAERUV
MODIS
OMAERO
P-3
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Comparison of AATS, OMI, and MODIS AOD spectra
Preliminary
J. Redemann, J. Livingston, Torres, Veihelmann,
Veefkind
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ARCTAS 30 June 2008
P-3B Flight Track
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ARCTAS 30 June 2008
Note Google Map from July 1, 1545 UT
P-3B flight track color-coded by AATS AOD (451 nm)
AATS 19.65-19.95 UT Aqua 19.83 UT
Aura 20.01 UT
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ARCTAS 30 June 2008
OMI retrievals in highlighted cells likely
cloud-contaminated
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ARCTAS 30 June 2008
AATS
MODIS
OMAERO
OMAERUV
MODIS AOD (470 nm)
MODIS
OMI
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The first half of the P-3 July 3 flight
220 km
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The first half of the P-3 July 3 flight
encountered a well-mixed local pollution layer up
to 2 km GPS altitude and a long-range transport
air mass above, both homogenous over gt200 km.
220 km
HiGEAR TSI Neph. Dry Scat. Coeff. (Mm-1) at 550 nm
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MODIS
PRELINARY MODIS 3-km resolution product from
Remer and Mattoo.
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MODIS
660 550 470 nm
15 0.05
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-15 - 0.05
(HiGEAR extinction radar altitude)
MODIS 3-km resolution product from Remer and
Mattoo.
MODIS underestimated the AOD in some pixels.
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CCN and optical properties
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CCN concentration at supersaturation 0.3 0.4
is related to the column AOD at 354 nm typically
with a geometric standard deviation of 3
(vertical bar). (Shown are data taken at GPS
Altitude lt 1000 m during ARCTAS Summer over
Canada only.)
(Lathem and Nenes)
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AOD does not tell near-surface extinction,
particularly with high scattering. We need to use
better assessment of extinction (e.g., HSRL).
lt1000 m GPS altitude
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CCN concentration is related to in-situ dry
extinction coefficient with a geometric standard
deviation of 2.
(Lathem and Nenes)
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aerosol composition and smoke type
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White smoke from smoldering fires
White smoldering and black flaming identified
based on Tony Clarkes flight report.
Dark smoke from flaming fires
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Smoke after evolution, or pollution from other
sources? To be investigated.
White smoke from smoldering fires
Aerosol evolution in downwind transport?
Characterization of smoke types and age with the
wavelength dependence of scattering and SSA
Dark smoke from flaming fires
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Summary

• AATS, HiGEAR and AERONET measurements of AOD
  agreed well, except for some profiles with high
  spatial variability associated with forest fire
  smoke.
• Comparison with satellite observations is in
  progress.
• CCN concentration is related to single wavelength
  light extinction typically with a geometric
  standard deviation of 2.
• Smoke type and age may be characterized by the
  wavelength dependence of scattering, that of
  absorption and SSA .
• Thanks Ellen Baum from the Clean Air Task Force
  for supporting my travel.

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Extra slides
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The humidity response of aerosol scattering was
often negligible in Canadas forest fire smoke we
sampled. Both gamma and ambient RH were almost
always too low to matter (gammalt 0.53 and ambient
RH lt50 for two thirds of our samples).
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CALIPSO profile, all adjacent pro-files yield no
aerosol retrieval
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