The LongRange Transport LRT of Pollution

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The Long-Range Transport (LRT) of Pollution

• Bryan Duncan

Goddard Earth Sciences Technology (GEST)
Center, University of Maryland, Baltimore
County Atmospheric Chemistry and Dynamics Branch
(Code 613.3), Goddard Space Flight Center
Langley August 11, 2008
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Presentation Outline

• Topics
• LRT of pollution to the Arctic
• ? ARCTAS field mission
• LRT of pollution from biomass burning regions
• ? 1997 2006 Indonesian wildfires
• LRT of anthropogenic pollution from Europe
• ? Consequences for human health downwind

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Topic 1 LRT to the Arctic
Arctic Research of the Composition of the
Troposphere from Aircraft and Satellites (ARCTAS)
Boreal Forest Fires - July
Arctic Haze (Anthropogenic Pollution) April
Northern Saskatchewan
Brooks Range, Alaska
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Arctic Research of the Composition of the
Troposphere from Aircraft and Satellites (ARCTAS)
Siberian Boreal Forest Fires July 1st
Russia
Sea of Okhotsk
China
Image from MODIS Rapid Response System
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Arctic Research of the Composition of the
Troposphere from Aircraft and Satellites (ARCTAS)
AIRS CO 500 mb June 26th - July 8th
ppbv
From Juying Warner (GEST UMBC)
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GEOS-5 GCM Carbon Monoxide 300 mb July 2nd
6th 2008
North Pole
East Asia
GSFC
Cold Lake
ppbv
From Peter Colarco
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Total CO 500 mb July 8th
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Total CO
1
2
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GEOS 5 GCM
Sulfate
Asian Fossil Fuel CO
1
2
Plume 1
Siberian Forest Fire CO
Organic Carbon
Plume 2
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Topic 2 LRT of Biomass Burning Pollution
Biomass Burning Agricultural and Forest Fires
Annual, Average Fire Emissions of CO
E Fossil Fuels E Biomass Burning
(x1019 molec/cm2/year)
Jennifer Logan, Harvard Univ. Duncan et al.
2003a
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Average Monthly Burning in Tropics
Subtropics (from AVHRR ATSR fire-counts)

Northern Hemisphere
Southern Hemisphere
J F M A M J
J A S O N D
Month
? Fires typically set in anticipation of
monsoonal rains.
Duncan et al. 2003a
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Interannual Variability of Fires
TOMS Aerosol Index Data Product
Relative Fire Emissions
Indonesia
1997-98
Monthly-Regional Aerosol Index
Year
Duncan et al. 2003a
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MLS CO at 215 mb November 2006
LRT in northern jet.
LRT in southern jet.
GMI CTM CO at 226 mb November 2006
LRT in easterlies.
Courtesy Y. Yoshida
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1997 Indonesian Forest Fires Impact on the
Troposphere Duncan et al., 2003b
CO Column Increase () in October
? Aerosols Net direct, shortwave radiative
forcing at the surface -150 W/m2 in burning
regions -10 W/m2 in tropical Indian Ocean
AOD Increase () in October
? Burden CO up to 17 higher OH up to 80
lower near fires up to 30 lower over
tropical Indian Ocean
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Indonesian Forest Fires

• Unanswered Questions of 2003 Study Duncan et
  al., 2003b
• Did the fire pollution reach the stratosphere?
• ? Yes, but poor representation of UT/LS
  processes.
• ? Global Modeling Initiatives (GMI) Combined
  Stratosphere/Troposphere CTM.
• 2) Did the fire aerosols impact
  troposphere-to-stratosphere transport?
• ? Current Research

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Troposphere-to-Stratosphere Transport (TST)
of Biomass Burning CO in the Tropics
Tropical CO Perturbation (i.e., mean removed)
GMI CTM Difference () in CO Upper Troposphere
in October
MLS
Convective lofting of CO
GMI
Schoeberl et al. 2006
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Troposphere-to-Stratosphere Transport (TST)
Two Major Pathways Duncan et al., 2007
Quasi-isentropic exchange in the subtropical
jets Large-scale, slow ascent in the
tropics Minor Pathway Deep convection
penetrating the stratosphere
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1997 Indonesian Forest Fires
Pathway 1 Quasi-Isentropic Exchange
GMI CTM Increase () in CO in October at 200 mb
LRT in easterlies.
LRT in southern subtropical jet.
Duncan et al. 2007
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Pathway 1 Quasi-Isentropic Exchange
October 1997 Increase () in CO 180? Longitude
Lower Stratosphere
Pressure (mb)
Upper Troposphere
LMS
Latitude
Yellow Lines Isentropes
Red Line Approximate Tropopause
? But, pollution in Lowermost Stratosphere (LMS)
returns to troposphere within a few months
COs lifetime is only 1 month.
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The Tropical Tropopause Layer (TTL)
Pathway 2 Slow, Large-Scale Ascent
Potential Temperature
Stratosphere
Convective overshoot
380K
18 km
Cold point tropopause
17 km
370K
Cirrus
heating
Zero Heating
360K
16 km
cooling
Cirrus
MLS Levels
Lapse rate minimum
12 km
350K
Top of Hadley Cell
Temperature
Most convection
After Gettleman and Forster, J. Met. Soc. Jpn.
from Mark Schoeberl
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Pathway 2 Slow, Large-Scale Ascent
November 1997 CO Perturbation ()
100 mb Near Tropical Tropopause
Latitude
Tropical Tropopause
80 mb Lower Stratosphere
Latitude
Longitude
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Tape Recorder
A tape recorder describes the seasonal
propagation of a trace gas from the tropical
tropopause to the lower stratosphere. Water
Vapor ? seasonal variation in temperature in
the TTL Carbon Monoxide ? seasonal variations
in CO emissions ? seasonal variations in
dynamics
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Average Monthly Burning in Tropics
Subtropics (from AVHRR ATSR fire-counts)

Semi-Annual Oscillation
Northern Hemisphere
Southern Hemisphere
J F M A M J
J A S O N D
Month
NOTE SYMMETRY of MINs MAXs
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Evolution of the Tropical CO Signal
LS
Annual Oscillation
TTL
Quasi-Annual Oscillation
Altitude
CO Perturbation (ppbv)
UT
Semi-Annual Oscillation
Month
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Tropical Tropopause Layer
Quasi-annual Oscillation
NH BB
Boreal winter high.
SH BB
Full Chemistry Constant Emission Tracer
Tracer of Dynamics
Austral winter low.
Month
Seasonally high transport acts to fill in
minimum in biomass burning CO, but thats not
the whole story.
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Tropical Tropopause Layer
CO by Source
Seasonally high transport and seasonally high CO
conspire to fill in minimum in biomass
burning CO.
Seasonally low transport and seasonally low CO
conspire to deepen minimum.
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Interannual Variability in the TTL Seasonal
emissions same each year.
CO Perturbation (ppbv) 1994-1998
1997-1998 strong El Niño
CO Perturbation (ppbv)
Month
? Convective mass flux at 300 mb 10 higher in
97-98, but
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1994-1996
IMPORTANT Locations of convection in relation to
CO sources.
Indonesia
S. America
Pacific Ocean
1997-1998

• 1997-1998
• S. American African CO sources were 2-3x higher
  during the El Niño.

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Indonesian Forest Fires

• Unanswered Questions of 2003 Study Duncan et
  al., 2003b
• Did the fire pollution reach the stratosphere?
• YES! Duncan et al., 2007 MLS CO
• 2) Did the fire aerosols impact
  troposphere-to-stratosphere transport?
• YES! Preliminary results.

? Using GEOS-5 GCM with Lesley Ott Steven
Pawson (GMAO). ? 1st Step Only simulate
radiative effects of aerosols. Fixed SSTs, no
effects on CCN, etc.
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Preliminary Results 2006 Indonesian Forest
FiresRadiative Impact of Aerosols (BCOC) on
Dynamics
CO (ppbv) at tropopause
with Indonesian aerosols
without Indonesian aerosols
ppbv
? Appears to be associated with changes in large
scale vertical velocity (?) due to radiative
heating.
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Topic 3 LRT of Anthropogenic Pollution
LRT of European Pollution Implications for Human
Health
Intercontinental transport typically
considered N. America ? Europe Europe ? E.
Asia E. Asia ? N. America such as in the
Hemispheric Transport of Air Pollution (HTAP)
study. BUT, European pollution is exported
mainly over land and to the Near East northern
Africa in summer Duncan et al.,
2004. Unanswered question of 2004 study Duncan
et al., 2004 What are the consequences for
human health? Duncan et al., 2008
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LRT of European Pollution
European pollution typically flows southward in
summer to the Mediterranean Sea region, a
photochemically favorable environment.
Population Density
Image from NASA Visible Earth
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GMI CTM European Contribution to Surface
Ozone (ppbv) in July 2001
?Ozone (ppbv)
Model surface ozone in northern Africa Near
East without European pollution 30-60 ppbv.
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Additional Violations of European Health Standard
for Ozone (60 ppbv as an 8-hr average)
Almost every day!
JULY
? 50-150 additional violations/year of European
health standard in northern Africa
Near/Middle East
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Premature Mortalities/Year
? 51,000 additional deaths/year ?19,000 in
northern Africa Near/Middle East ? 32,000
outside of Europe
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Future Work
Continue work with the LRT of pollution, but with
a focus on future climate.
GEOS Chemistry-Climate Model (collaboration
with GMAO) ? Impact of increasing biomass
burning rapid industrialization in the
tropics on mid-century atmospheric chemistry,
dynamics health. ARCTAS Analysis ? Full
chemistry model simulation analysis of LRT
pathways with satellite observations Mission
Planning GEO-CAPE ? Geostationary Coastal
Air Pollution Events
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