|
|
|
|
|
|
|
. |
|
|
Summary Report
for ONR Project Introduction In April 2000 we hosted Shoreline Environment Aerosol Study (SEAS) Experiment. Major SEAS objectives were: 1) Comparison of lidar backscatter and extinction with in-situ measurements for aerosol produced from coastal breaking wave and 2) Characterization of coastal aerosol fields, their nature and evolution and their coupling to ocean and atmospheric dynamics. SEAS Site and Time: Location - BAFB and coast on eastern OAHU; Facilities: 20m Tower, 200A of 110/220 power; meteorological support; phone and data lines, lab space, 17’ boat or larger, RPV; Time Frame: April of 2000; Duration: 2 weeks for data collection and a week for set-up, tests and shut-down. 3 weeks total in field.
Instrumentation and Participants a. Tower and aerosol instrumentation (A. Clarke et al.) b. Scanning Lidar (S. Sharma et al.) c. Lidar Backscatter Nephelometer (Covert et al.) d. Aerosol Sodium Detector (Eric Saltzman et al.) e. Polar nephelometer (J. Porter et al.) f. Bistatic nephelometer (A. Hunt et al.) g. UAV development (A. Clarke et al.) h.Theoretical analysis of aerosol optics (K.S. Shifrin et al.) Synoptic Situation, Aerosol Properties and Air Mass Trajectories Aerosol Size Distributions and Optical Parameters Vaisala Ceilometer and Visibility Meter Comparison Lidar Measurements of Aerosol and Water Vapor (S. Sharma et al.) Measurement of Extinction-to-backscatter Ratio( D. Covert et al. ) Aerosol Sodium Detector (Eric Saltzman et al.)
The measurements described in this report were made on a coastal UH research site in spring 2000 during Shoreline Environment Aerosol Study (SEAS, April 21-30, 2000). The SEAS was designed as an intensive study to bring together various ONR funded investigators with new instrumentation developed to enhance our capabilities in characterizing oceanic and coastal aerosol. The SEAS experiment included new measurements of the coastal aerosol with 3-D scanning lidar systems (Sharma et al.), measurements of the aerosol lidar backscatter coefficient (Covert et al.), the aerosol phase functions (Porter, Hunt); aerosol microphysics and optics (Clark et al.) and size-resolved sodium chemistry of single particles (Saltzman et al.). Scattering and attenuation of natural and artificial light in the marine boundary layer (MBL) is of concern for both civilian and military operations. Atmospheric attenuation adversely affects laser target ranging, optical data communications, remote sensing and visibility. The main factors in this atmospheric attenuation are aerosol, Rayleigh scattering, water vapor and temperature inhomogeneities. Often, aerosols are the most uncertain factor in modeling electro-optical attenuation in the visible and near infrared (NIR) spectral region. Atmospheric aerosol also plays an important role in many atmospheric processes such as cloud formation and radiative transfer in the atmosphere. In unpolluted regions close to the ocean’s surface a large portion of this aerosol consists of sea salt and organics generated by wave/wind interaction. While there have been a number of studies examining sea-salt concentrations and optical effects for the open ocean, few have looked at these relationships in a coastal environment. In this environment, aerosol production is more complex because of the interaction of processes that do not play a role in the open ocean, like waves breaking on the shore and on offshore reefs and tides and swells. In locally unpolluted regions we can expect that the main factors affecting scattering and extinction will be the sea salt aerosol production from breaking waves superimposed on an open ocean aerosol. We will show that both factors – sea salt aerosol and background aerosol are equally important and that the properties of the latter can reflect transport above the boundary layer
|
||||||||||||||||||||||||||||||||||||||||||||
|
Last Modified: Mar 06, '01 |
