HR: 1340h
AN: A13B-0924    [Abstracts]
TI: Observation of Enhanced Organic Aerosol Concentrations Above Cloudtops in Marine Stratus Experiment (MASE2005) off the Northern California Coast
AU: * Alexander, M L
EM: michael.alexander@pnl.gov
AF: Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 United States
AU: Hubbe, J M
EM: john.hubbe@pnl.gov
AF: Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA 99352 United States
AU: Lee, Y
EM: ynlee@bnl.gov
AF: Brookhaven National Laboratory, MS815E , Upton, NY 11973-5000 United States
AU: Wang, J
EM: jian@bnl.gov
AF: Brookhaven National Laboratory, MS815E , Upton, NY 11973-5000 United States
AU: Senum, G
EM: gsenum@bnl.gov
AF: Brookhaven National Laboratory, MS815E , Upton, NY 11973-5000 United States
AU: Daum, P H
EM: phdaum@bnl.gov
AF: Brookhaven National Laboratory, MS815E , Upton, NY 11973-5000 United States
AU: Murphy, S
EM: shanem@caltech.edu
AF: California Institute of Technology - Dept. of Chemical Engineering, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Flagan, R C
EM: flagan@caltech.edu
AF: California Institute of Technology - Dept. of Chemical Engineering, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Varunbangkul, V
EM: tomtor@caltech.edu
AF: California Institute of Technology - Dept. of Chemical Engineering, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Rissman, T A
EM: rissman@caltech.edu
AF: California Institute of Technology - Dept. of Chemical Engineering, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Sorooshian, A
EM: armin@caltech.edu
AF: California Institute of Technology - Dept. of Chemical Engineering, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Seinfeld, J H
EM: seinfeld@caltech.edu
AF: California Institute of Technology - Dept. of Chemical Engineering, 1200 E. California Blvd., Pasadena, CA 91125 United States
AU: Hudson, J G
EM: hudson@dri.edu
AF: Desert Research Institute- University of Nevada, 2215 Raggio Pkwy, Reno, NV 89512 United States
AU: Jayne, J
EM: jayne@aerodyne.com
AF: Aerodyne Research Inc., 45 Manning Road , Billerica, MA 01821-3976 United States
AB: We report the observation of a layer of organic aerosols above marine cloud tops at concentrations that are enhanced relative to levels below cloud and immediately above the ocean surface. These observations were made from two separate aircraft, a De Havilland Twin Otter(CIRPAS) containing an Aerodyne time-of-flight aerosol mass spectrometer(TOF-AMS)and a Gulfstream G1(Battelle, Dept. of Energy) containing an Aerodyne quadrupole AMS. Both aircraft were equipped with an array of complimentary equipment including CCN counters, laser particle measurement systems, meterological instrumentation and particle-into-liquid samplers (PILS). The G1 also contained gas phase ozone and SO2 measurements while the Twin Otter was equipped with a counterflow virtual impactor (CVI) for exclusively sampling ambient nucleated particles. Data from the AMS instruments on both aircraft clearly indicate the presence of a stable enhanced organic particulate layer, approximately 30-60 m above cloud top and 30-60 m thick. A slight temperature inversion was observed in the enhanced layer. The concentration of organic particles was enhanced by a factor of 4-5 over the concentrations observed below the clouds while the sulfate concentrations decreased slightly. Below cloud the organic and sulfate particle concentrations were almost equal while above cloud the organic levels were over 5 times higher due to the observed enhancement. Particle size distributions for organics and sulfate were almost identical below cloud, peaking at 400 nm, while the above cloud the organics shifted to 250 nm with the sulfates remaining peaked at 400 nm. The shift in size distribution for the organic aerosols suggests that organics and sulfates are heterogeneously mixed above cloud, possibly due to a mechanism for formation of new organic aerosols. Updated results from MASE2005 will be presented, integrating the AMS data with measurements from the complimentary instrumentation and providing possible interpretations of these results.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0312 Air/sea constituent fluxes (3339, 4504)
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0320 Cloud physics and chemistry
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005