Articles | Volume 16, issue 22
Atmos. Chem. Phys., 16, 14057–14078, 2016
Atmos. Chem. Phys., 16, 14057–14078, 2016

Research article 15 Nov 2016

Research article | 15 Nov 2016

Aerosol meteorology of Maritime Continent for the 2012 7SEAS southwest monsoon intensive study – Part 2: Philippine receptor observations of fine-scale aerosol behavior

Jeffrey S. Reid1, Nofel D. Lagrosas2, Haflidi H. Jonsson3, Elizabeth A. Reid1, Samuel A. Atwood4, Thomas J. Boyd5, Virendra P. Ghate6, Peng Xian1, Derek J. Posselt7, James B. Simpas2, Sherdon N. Uy2, Kimo Zaiger8, Donald R. Blake9, Anthony Bucholtz1, James R. Campbell1, Boon Ning Chew10, Steven S. Cliff11, Brent N. Holben12, Robert E. Holz13, Edward J. Hyer1, Sonia M. Kreidenweis4, Arunas P. Kuciauskas1, Simone Lolli14, Min Oo13, Kevin D. Perry15, Santo V. Salinas16, Walter R. Sessions13, Alexander Smirnov17, Annette L. Walker1, Qing Wang3, Liya Yu18, Jianglong Zhang19, and Yongjing Zhao11 Jeffrey S. Reid et al.
  • 1Marine Meteorology Division, Naval Research Laboratory, Monterey, CA, USA
  • 2Manila Observatory, Manila, Philippines
  • 3Department of Meteorology, Naval Postgraduate School, Monterey, CA, USA
  • 4Dept. of Atmospheric Science, Colorado State University, Ft. Collins, CO, USA
  • 5Marine Biogeochemistry Section, Naval Research Laboratory, Washington, DC, USA
  • 6Argonne National Laboratory, Argonne, IL, USA
  • 7Dept. of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, MI, USA
  • 8NAVFAC Engineering and Expeditionary Warfare Center Port Hueneme, CA, USA
  • 9Dept. of Chemistry, University of California, Irvine, CA, USA
  • 10Meteorological Service, Singapore
  • 11Department of Applied Science, University of California Davis, CA, USA
  • 12NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • 13Space Science Engineering Center, University of Wisconsin, Madison, WI, USA
  • 14University of Maryland Baltimore County-JCET, Baltimore, MD, USA
  • 15University of Utah, Salt Lake City, UT, USA
  • 16Centre for Remote Imaging Sensing and Processing, National University of Singapore, Singapore
  • 17Science Systems and Applications, Inc., Lanham, MD, USA
  • 18Dept. of Environmental Engineering, National University of Singapore, Singapore
  • 19Dept. of Atmospheric Science, University of North Dakota, Grand Forks, ND, USA

Abstract. The largest 7 Southeast Asian Studies (7SEAS) operations period within the Maritime Continent (MC) occurred in the August–September 2012 biomass burning season. Data included were observations aboard the M/Y Vasco, dispatched to the Palawan Archipelago and Sulu Sea of the Philippines for September 2012. At these locations, the Vasco observed MC smoke and pollution entering the southwest monsoon (SWM) monsoonal trough. Here we describe the research cruise findings and the finer-scale aerosol meteorology of this convectively active region. This 2012 cruise complemented a 2-week cruise in 2011 and was generally consistent with previous findings in terms of how smoke emission and transport related to monsoonal flows, tropical cyclones (TC), and the covariance between smoke transport events and the atmosphere's thermodynamic structure. Biomass burning plumes were usually mixed with significant amounts of anthropogenic pollution. Also key to aerosol behavior were squall lines and cold pools propagating across the South China Sea (SCS) and scavenging aerosol particles in their path. However, the 2012 cruise showed much higher modulation in aerosol frequency than its 2011 counterpart. Whereas in 2011 large synoptic-scale aerosol events transported high concentrations of smoke into the Philippines over days, in 2012 measured aerosol events exhibited a much shorter-term variation, sometimes only 3–12 h. Strong monsoonal flow reversals were also experienced in 2012. Nucleation events in cleaner and polluted conditions, as well as in urban plumes, were observed. Perhaps most interestingly, several cases of squall lines preceding major aerosol events were observed, as opposed to 2011 observations where these lines largely scavenged aerosol particles from the marine boundary layer. Combined, these observations indicate pockets of high and low particle counts that are not uncommon in the region. These perturbations are difficult to observe by satellite and very difficult to model. Indeed, the Navy Aerosol Analysis and Prediction System (NAAPS) simulations captured longer period aerosol events quite well but largely failed to capture the timing of high-frequency phenomena. Ultimately, the research findings of these cruises demonstrate the real world challenges of satellite-based missions, significant aerosol life cycle questions such as those the future Aerosol/Clouds/Ecosystems (ACE) will investigate, and the importance of small-scale phenomena such as sea breezes, squall lines, and nucleation events embedded within SWM patterns in dominating aerosol life cycle and potential relationships to clouds.

Short summary
This paper describes aspects of the 2012 7 Southeast Asian Studies (7SEAS) operations period, the largest within the Maritime Continent. Included were an enhanced deployment of Aerosol Robotic Network (AERONET) sun photometers, multiple lidars, and a Singapore supersite. Simultaneously, a ship was dispatched to the Palawan Archipelago and Sulu Sea of the Philippines for September 2012 to observe transported smoke and pollution as it entered the southwest monsoon trough.