HR: 0800h
AN: A31A-0824 [Abstracts]
TI: The Impact of Continental Outflow on Chemical and Aerosol Distributions Off the Northeast Coast of the
U.S. During INTEX-NA
AU: * Thornhill, L
EM: k.l.thornhill@larc.nasa.gov
AF: Science Applications Int. Corp., 1 Enterprise Parkway
Suite 300, Hampton, VA 23666
United States
AU: Anderson, B E
EM: b.e.anderson@larc.nasa.gov
AF: NASA Langley Research Center, 21 Langley Blvd
MS 483, Hampton, VA 23681
United States
AU: Chen, G
EM: gao.chen-1@nasa.gov
AF: NASA Langley Research Center, 21 Langley Blvd
MS 483, Hampton, VA 23681
United States
AU: Winstead, E
EM: e.l.winstead@larc.nasa.gov
AF: GATS, 21 Langley Blvd
MS 483, Hampton, VA 23681
United States
AU: Clarke, A D
EM: tclarke@soest.hawaii.edu
AF: School of Ocean and Earth Science and Technology, 1000 Pope Road
Univeristy of Hawaii, Honolulu, Hi 96822
United States
AU: Shinozuka, Y
EM: yohei@hawaii.edu
AF: School of Ocean and Earth Science and Technology, 1000 Pope Road
Univeristy of Hawaii, Honolulu, Hi 96822
United States
AU: McNaughton, C S
EM: cameronm@soest.hawaii.edu
AF: School of Ocean and Earth Science and Technology, 1000 Pope Road
Univeristy of Hawaii, Honolulu, Hi 96822
United States
AU: Howell, S G
EM: showell@soest.hawaii.edu
AF: School of Ocean and Earth Science and Technology, 1000 Pope Road
Univeristy of Hawaii, Honolulu, Hi 96822
United States
AU: Dibb, J E
EM: jack.dibb@unh.edu
AF: Institute for the
Study of Earth,
Oceans, and Space, Morse Hall
Univ. of New Hampshire
39 College Road, Durham, NH 03824
United States
AU: Scheuer, E
EM: eric.scheuer@unh.edu
AF: Institute for the
Study of Earth,
Oceans, and Space, Morse Hall
Univ. of New Hampshire
39 College Road, Durham, NH 03824
United States
AB:
The outflow of continental air from North America significantly impacts chemical and aerosol distributions over the western
Atlantic region. To more thoroughly document and gain a better understanding of these impacts, NASA conducted the
Intercontinental Transport and Chemical Evolution Experiment over North America (INTEX-NA), a large-scale field experiment
that coupled observations from ground sites, aircraft, and satellites to address a diverse set of scientific objectives.
Performed from three intensive sites across the United States during summer 2004, the mission was designed to coincide with
the maximum in the eastward transport of dust and pollution. It employed the NASA DC-8 equipped with a variety of remote and
in situ instruments to provide surveys of tropospheric composition within a study area that encompassed the entire
continental U.S., southern Canada, and the western north Atlantic. A major INTEX-NA objective was to examine the evolution of
aerosol and trace species concentrations and characteristics during transport away from continental source regions. To
address this objective, we performed a detailed analysis of satellite as well as the DC-8 data collected in three,
approximately 5 degree-wide longitudinal swaths along the U.S. northeast coastline. In situ observations from these on-shore
(coast to 500 km inland) , near-shore (coast to 500 km offshore), and off-shore (> 500 km offshore) regions were further
separated according to CO mixing ratio into clean, intermediate, and polluted cases. Average profiles of a variety of
chemical tracers and aerosol parameters were examined to establish the gradient in chemical and aerosol concentrations as a
function of distance from shore. Initial results indicate that CO values and aerosol scattering were significantly lower in
the offshore airmasses. Aerosol concentrations for particles less than 0.3 æm also exhibited a sharp falloff (about 50%)
between both the on-shore and near-shore data and the near-shore/off-shore data. Correspondingly, at altitudes below 2 km,
fine aerosol sulfate mixing ratios exhibited a marked decline between the on-shore and near-shore data, although the
near-shore and off-shore values were very similar. Chemically, there was a sharp decrease in CH2O, SO2, and NOx between the
on-shore and the near/off-shore observations. Remotely sensed aerosol optical depths also decrease significantly with
distance from the coast, declining, on average, by a factor of 6 between the on-shore and off-shore regions. Aerosol
advective fluxes to the western Atlantic were also derived from the in situ and remote observations and will be discussed in
the presentation.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 4801 Aerosols (0305, 4906)
DE: 4906 Aerosols (0305, 4801)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005