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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
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© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

  28 Sep 2020

28 Sep 2020

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This preprint is currently under review for the journal ACP.

Long-range transport patterns into the tropical northwest Pacific during the CAMP2Ex aircraft campaign: chemical composition, size distributions, and the impact of convection

Miguel Ricardo A. Hilario1,a, Ewan Crosbie2,3, Michael Shook2, Jeffrey S. Reid4, Maria Obiminda L. Cambaliza1,5, James Bernard B. Simpas1,5, Luke Ziemba2, Joshua P. DiGangi2, Glenn S. Diskin2, Phu Nguyen6, Joseph Turk7, Edward Winstead2,3, Claire E. Robinson2,3, Jian Wang8, Jiaoshi Zhang8, Yang Wang9, Subin Yoon10, James Flynn10, Sergio L. Alvarez10, Ali Behrangi11,12, and Armin Sorooshian11,13 Miguel Ricardo A. Hilario et al.
  • 1Manila Observatory, Quezon City 1108, Philippines
  • 2NASA Langley Research Center, Hampton, VA, USA
  • 3Science Systems and Applications, Inc., Hampton, VA, USA
  • 4Marine Meteorology Division, Naval Research Laboratory, Monterey, CA, USA
  • 5Department of Physics, Ateneo de Manila University, Quezon City 1108, Philippines
  • 6Department of Civil & Environmental Engineering, University of California Irvine, Irvine, CA 92697, USA
  • 7NASA Jet Propulsion Laboratory, Pasadena, CA, USA
  • 8Center for Aerosol Science and Engineering, Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
  • 9Department of Civil, Architectural and Environmental Engineering, Missouri University of Science and Technology, Rolla, MO 65409, USA
  • 10Department of Earth and Atmospheric Science, University of Houston, Texas, 77204, USA
  • 11Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ 85721, USA
  • 12Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA
  • 13Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ 85721, USA
  • anow at: Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ 85721, USA

Abstract. The tropical Western North Pacific (TWNP) is a receptor for pollution sources throughout Asia and is highly susceptible to climate change, making it imperative to understand long-range transport in this complex aerosol-meteorological environment. Measurements from the NASA Cloud, Aerosol, and Monsoon Processes Philippines Experiment (CAMP2Ex; 24 Aug to 5 Oct 2019) and back trajectories from the National Oceanic and Atmospheric Administration Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) were used to examine transport into the TWNP from the Maritime Continent (MC), Peninsular Southeast Asia (PSEA), East Asia (EA), and West Pacific (WP). A mid-campaign monsoon shift on 20 Sep 2019 led to distinct transport patterns between the southwest monsoon (before 20 Sep) and monsoon transition (after 20 Sep). During the southwest monsoon, long-range transport was a function of southwesterly winds and cyclones over the South China Sea. Low (high) altitude air generally came from MC (PSEA), implying distinct aerosol processing related to convection and perhaps wind shear. The monsoon transition saw transport from EA and WP, driven by Pacific northeasterly winds, continental anticyclones, and cyclones over the East China Sea. Composition of transported air differed by emission source and accumulated precipitation along trajectories (APT) as an indicator of convection. MC air was characterized by biomass burning tracers while major components of EA air pointed to Asian outflow and secondary formation. Convective scavenging of PSEA air was evidenced by considerable vertical differences between aerosol species but not trace gases, as well as notably higher APT and smaller particles than other regions. Finally, we observed a possible wet scavenging mechanism acting on MC air aloft that was not strictly linked to precipitation. These results are important for understanding the transport and processing of air masses with further implications for modeling aerosol lifecycles and guiding international policymaking on public health and climate.

Miguel Ricardo A. Hilario et al.

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Miguel Ricardo A. Hilario et al.

Miguel Ricardo A. Hilario et al.


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Publications Copernicus
Short summary
This study characterizes long-range transport from major Asian pollution sources into the northwest Pacific and the impact of scavenging on these air masses. We combined aircraft observations, HYSPLIT trajectories, reanalysis, and satellite retrievals to reveal distinct composition and size distribution profiles associated with specific emission sources and wet scavenging. Results of this work have implications international policymaking related to climate and health.
This study characterizes long-range transport from major Asian pollution sources into the...