HR: 10:50h
AN: A42A-03    [Abstracts]
TI: Trans-Pacific Transport of Asian Dust During INTEX B
AU: * Dibb, J E
EM: jack.dibb@unh.edu
AF: CCRC/EOS/UNH, Morse Hall 39 College Road, Durham, NH 03824, United States
AU: Scheuer, E
EM: eric.scheuer@unh.edu
AF: CCRC/EOS/UNH, Morse Hall 39 College Road, Durham, NH 03824, United States
AB: NASA's tropospheric chemistry program has deployed the DC-8 airborne laboratory to the northern Pacific four times since 1991 to study Asian outflow. During the most recent campaign (INTEX B in Spring 2006) sorties were conducted from Hawaii and Alaska to intercept Asian plumes several days or more downwind of the continent. Previous missions (PEM West A and B, TRACE P) sampled similar regions over the central and eastern north Pacific, but also included flights from Japan and Hong Kong targeting fresher Asian emissions. Enhancements of non-seasalt aerosol-associated Ca²⁺ were encountered throughout the depth of the troposphere on nearly all INTEX B flights over the Pacific, contrasting much lower dust loadings in these regions in the earlier campaigns. INTEX B dust plumes were generally associated with enhanced levels of aerosol NO₃^-, consistent with previous observations of uptake of HNO₃ by Asian dust immediately downwind of Asia (e.g., during TRACE P and ACE Asia). Enhancements of non-seasalt SO₄⁼ also characterized many of the INTEX B dust plumes, reflecting long-range transport of a mixture of dust and pollution from Asia eastward. The increase in observed dust over the remote Pacific during INTEX B compared to TRACE P may be partly due to more favorable transport, but also reflects increasing emissions from Asian source regions.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0330 Geochemical cycles (1030)
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting