Satellitebased Estimates of Transpacific Transport of Pollution Aerosol

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Satellite-based Estimates of Transpacific
Transport of Pollution Aerosol
Hongbin Yu, Lorraine Remer, Mian Chin Goddard
Aerosol Update 2007
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Motivation

• Aerosols can transport thousands of miles
• Important implications on local, regional,
  hemispheric/global scale
• Climate change
• Air quality human health
• Biogeochemistry

Air pollution is a global problem that requires a
global solution!
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A Satellite-based Approach

• New and enhanced satellite sensors (A-Train) are
  measuring aerosols with high accuracy
• multi-wavelength, multi-angle, polarization,
  lidar
• MODIS separates fine- and coarse-mode aerosol
  (over ocean)
• pollution vs dust (Kaufman et al., 2005)
• we are taking one step further by estimating
  mass flux of trans-boundary transport of
  pollution aerosol (in combination with in-situ
  measurements and model simulations)
• The satellite-based approach can play a role in
• Expanding temporal spatial scale of field
  campaigns
• Evaluating constraining model simulations

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Estimate pollution mass flux across red boxes
(E-W winds)
export
import
CHINA
USA
West Pacific
East Pacific
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Annual Export and Import Fluxes (2004)
Latitude
FLUX (Tg/yr)
For annual and mid-latitude integration 28 of
pollution exported to West Pacific (largely from
Asia) reached the west coast of North America,
compared to GOCARTs 33.
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Seasonal Variations of mid-latitude Pollution
Fluxes
MODIS-GOCART differences less than 30 (mostly
lt15) Pollution outflow is strongest in spring,
followed by winter, consistent with previous
analysis.
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Inter-annual Variability Pollution AOD
(corroborated with elevated TOMS AI)
Intense Eurasia boreal forest fires
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Inter-annual Variability
Max/Min1.6 Max/Min1.5
Max/Min1.3 Max/Min1.2
AOD
Max/Min1.6 Max/Min1.8
Max/Min2.0 Max/Min1.4
FLUX
Summer
Spring
30?N-60?N
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Estimation of Uncertainties

• Pollution AOD (30)
• Mass extinction efficiency (30)
• Humidification growth f(RH) (20)
• Transport heights (10-55)
• Using MODIS measurements to represent diurnal
  average (10)

Overall uncertainty 50 - 72
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Summary

• 30 pollution aerosol exported from East Asia
  arrives in the west coast of North America,
  consistent with GOCART simulations.
• The export and import pollution fluxes are
  largest in spring, followed by winter.
• The strongest pollution export occurred in 2003
  during the examined period (2002-2005).
• Overall uncertainty for pollution flux is
  estimated to be 50-72.
• A reduction of uncertainty can be achieved with
  A-Train data
• CALIPSO aerosol profiles
• PARASOL separation of spherical and non-spherical
  particles (a better characterization of
  anthropogenic aerosol)