LONG-RANGE TRANSPORT OF BLACK CARBON TO THE ARCTIC REGION

Qinbin Li¹, Daven Henze², Yang Chen¹, Evan Lyons³, Jim Randerson³

work supported by JPL/NASA

¹JPL ²Caltech ³UC Irvine

Arctic Research of the Composition of the Troposphere �from Aircraft and Satellites (ARCTAS)

ARCTAS to be conducted in spring and summer 2008 (two phases)

as part of the POLARCAT program during the International Polar Year (IPY)

ARCTAS

EXPORT OF BC FROM ASIA: GEOS-3 vs. GEOS-4

STRONGER EXPORT OF BC IN THE FREE TROPOSPHERE WITH GEOS-Chem DRIVEN BY GEOS4 MET DATA.

Vertical distributions of BC during TRACE-P

Park et al. [2005]

GEOS-3

GEOS-4

TRACE-P OBS.

TRACE-P OBS.

Monthly BC profiles [124-140°E, 30-40°N]

Long-term measurements of BC:

- Alert (62.8ºW, 82.7ºN) m_BC , δ_ap (Aethalometer, PSAP)

- Barrow (156.6ºE, 71.3ºN) δ_ap (PSAP)

- Ny Ålesund (11.9ºE, 78.9ºN) AOD (sun photometer)

​

How well does the model simulate BC in northern high-latitudes?

MEASUREMENTS OF BC IN HIGH-LATITUDES

BC @ ALERT (62.8ºW, 82.7ºN)

• BC component of the spring ‘Arctic Haze’ is significantly underestimated in the model. Better agreements for the summer months.
• Little difference between the two model simulations driven by GEOS-3 vs. GEOS-4.

Data from World Data Center for Aerosols (http://wdca.jrc.it/)

Green - CMDL obs.

Blue - GC w/ GEOS-3

Red - GC w/ GEOS-4

need to filter out contamination

• Underestimate of BC in ‘Arctic Haze’.
• High BC levels from biomass burning in summer seen in both model results and (limited) observations.
• Model results with GEOS-4 met. data show substantially higher BC values vs. those w/ GEOS-3 met. data.

BC @ BARROW (156.6ºE, 71.3ºN)

Green - CMDL obs.

Blue - GC w/ GEOS-3

Red - GC w/ GEOS-4

Data from CMDL (ftp.cmdl.noaa.gov/aerosol/)

Mass absorption efficiency - 10 m²/g

(ADJOINT) SENSITIVITY OF ARCTIC TROPOSPHERIC

(70-90°N, 800-400 hPa) BC LOADING TO EMISSIONS

April 2001

DOMINANT INFLUENCE FROM EUROPEAN AND ASIA (CHINA) FOSSIL FUEL EMISSIONS.

BC EMISSIONS

SENTIVITY

SENSITIVITY OF ARCTIC BC LOADING TO FOSSIL FUEL EMISSIONS

April 2001

SURFACE

~950-850 hPa

~750-400 hPa

~300-150 hPa

SENSITIVITY OF ARCTIC BC LOADING TO BIOMASS BURNING EMISSIONS

April 2001

SURFACE

~950-850 hPa

~750-400 hPa

~300-150 hPa

(ADJOINT) SENSITIVITY OF ARCTIC TROPOSPHERIC

(70-90°N, 800-400 hPa) BC LOADING TO EMISSIONS

July 2001

DOMINANT INFLUENCE FROM BOREAL FOREST FIRE AND EUROPEAN FOSSIL FUEL EMISSIONS.

SENTIVITY

BC EMISSIONS

SENSITIVITY OF ARCTIC BC LOADING TO EMISSIONS

July 2001

SURFACE

~750-400 hPa

SURFACE

~750-400 hPa

Fossil Fuel

Biomass burning

DIURNAL CYCLE OF BIOMASS BURNING

BC AOD with monthly GFED emissions

BC AOD with 8-day GFED emissions

including diurnal cycle

TRANSPORT OF BOREAL FOREST FIRE BC EMISSIONS: effects of including (fire) diurnal cycle

Including diurnal cycle of fires results in less efficient transport of boreal forest fire emissions in Alaska while more efficient in southern Africa.

T

WIND

RH

PRECIP

ISI

GOES

FIRE COUNTS

INITIAL SPREAD INDEX AND MODELED EMISSIONS FOR ALASKA

EMISSIONS

GEOS Precipitation Alaska GPCP Precipitation

Red: ISI modeled emissions, Green: GFED, Black: GOES