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School of Ocean and Earth Science and Technology  .  University of Hawai‘i at Mānoa
 
stripes Atmospheric Research

Passive Aerosol And Water Vapor Measurements.
passive aerosol measurements  water vapor measurements
Atmospheric aerosol and water vapor affect a variety of processes including the earth's albedo, the earth's green house effect, cloud precipitation efficiency, visibility, and environmental quality. The radiative effects of these variable atmospheric constituents can have a major impact on regional and global scale climate. Correctly modeling these effects in climate models has yet to be achieved and requires improvements in both satellite and in situ measurement capabilities. Satellites are the logical approach to measure aerosol and water vapor properties on large scales. Satellite images near Hawaii from the GOES, AVHRR, SeaWifs, FY-C1, and MODIS satellites are being collected by Torben Nielsen and processed by John Porter to study aerosol and water vapor effects. Inherent in most of the aerosol studies is the ability to characterize the aerosol concentration, size distribution, and chemical properties. In order to validate the satellite products and better characterize the aerosol optical properties, insitu measurements are made on ship and aircraft experiments. Measurements include sun photometer measurements, sky-surface radiance measurements, irradiance measurements, and polar nephelometer measurements. Both standard radiation codes as well as new Monte Carlo radiation codes are run to characterize and understand the radiative effects of the aerosol and water vapor fields. Further details can be seen at http://www.soest.hawaii.edu/porter.

Lidar Measurements.
LIDAR measurements   
Lidar (LIght Detection And Ranging) is used to study the properties of the atmosphere using a laser light source and collecting light scattered from atmospheric aerosol and molecules. The scattered light is collected with a large telescope and measured using sensitive detectors. Realistic aerosol models are used to convert the scattered light to aerosol optical concentrations. Possible aerosol types include accumulation mode aerosol (gas-particle conversion from biological, volcanic and anthropogenic gases) and coarse mode aerosol (salt spray and dust) In order to characterize more of the spatial structure we have developed a scanning lidar that uses a pair of computer-controlled mirrors to simultaneously direct the laser and telescope direction. We are then able to scan the atmosphere in a short time enabling us to map out the aerosol fields out to distances of 10 km and greater. Since 1997, we have been using this system to map the spatial characteristics of aerosols generated above the surface of the ocean at two sites on the North east shore of O'ahu. Shiv Sharma, Barry Lienert and John Porter are directly involved in this effort. Further details can be viewed at http://www.soest.hawaii.edu/lidar.

Spectral Measurements of Volcanic SO2 Emissions.
Keith Horton has developed a UV correlation spectrometer (named FLYSPEC). This portable instrument is being used as an on-site tool for locating sources of volcanic emissions, mapping SO2 concentration levels from volcanic plumes, and as a ground-truth correlation tool for remote sensing systems.

For more information on Atmospheric Research at HIGP contact John Porter, Shiv Sharma, Barry Lienert, Keith Horton.

Text and images courtesy John Porter, Barry Lienert, HIGP.

  Updated 18 March 2010.


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