Feasibility of Shipboard Laser-Attenuation Measurements With a Portable Transmissometer.
A 2-meter-long cell has been devised in which aerosol extinction and scattering coefficients can be measured simultaneously. Extinction is obtained by measuring the change in the intensity of a HeNe laser beam which is stepped through the cell for a total path length of 20 meters. A reciprocal nephe...
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ftdtic:ADA067665 2023-05-15T17:34:36+02:00 Feasibility of Shipboard Laser-Attenuation Measurements With a Portable Transmissometer. Gerber,H NAVAL RESEARCH LAB WASHINGTON D C 1979-02-26 text/html http://www.dtic.mil/docs/citations/ADA067665 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA067665 en eng http://www.dtic.mil/docs/citations/ADA067665 APPROVED FOR PUBLIC RELEASE DTIC AND NTIS Meteorology Lasers and Masers *ATMOSPHERIC SCATTERING *TRANSMISSOMETERS *NEPHELOMETERS PORTABLE EQUIPMENT EXTINCTION AEROSOLS RESOLUTION REFRACTIVE INDEX LASER BEAMS TRANSMITTANCE MARINE ATMOSPHERES COEFFICIENTS SHIPBOARD ATTENUATION HELIUM NEON LASERS ABSORPTION COEFFICIENTS PE62759N wua0314b Text 1979 ftdtic 2016-02-20T15:53:57Z A 2-meter-long cell has been devised in which aerosol extinction and scattering coefficients can be measured simultaneously. Extinction is obtained by measuring the change in the intensity of a HeNe laser beam which is stepped through the cell for a total path length of 20 meters. A reciprocal nephelometer consisting of a sensor with a precise Lambertian response is mounted on the side of the cell to give a direct measure of the scattering coefficient. Filling the cell with ambient aerosol that has been concentrated centrifugally increases the effective path length of the beam in the cell to 300 meters. The cell was taken on the 1977 EOMET cruise of the USNS Hayes in order to determine its capabilities when exposed to the rigors of a ship's environment. The variance of data collected during the cruise was analyzed. The mean resolution limit of the transmittance measurements made during the cruise was + or - 0.16%. This limit was primarily influenced by mechanical instabilities in the nephelometer operated precisely. Vibrations from the ship's machinery was damped out successfully. An improved cell could increase the resolution by a factor of 10 or more. Absorption coefficients of the aersol particles in the eastern North Atlantic and in the Mediterranean were plotted. This technique has potential in the infrared. (Author) Text North Atlantic Defense Technical Information Center: DTIC Technical Reports database Hayes ENVELOPE(-64.167,-64.167,-66.833,-66.833) |
institution |
Open Polar |
collection |
Defense Technical Information Center: DTIC Technical Reports database |
op_collection_id |
ftdtic |
language |
English |
topic |
Meteorology Lasers and Masers *ATMOSPHERIC SCATTERING *TRANSMISSOMETERS *NEPHELOMETERS PORTABLE EQUIPMENT EXTINCTION AEROSOLS RESOLUTION REFRACTIVE INDEX LASER BEAMS TRANSMITTANCE MARINE ATMOSPHERES COEFFICIENTS SHIPBOARD ATTENUATION HELIUM NEON LASERS ABSORPTION COEFFICIENTS PE62759N wua0314b |
spellingShingle |
Meteorology Lasers and Masers *ATMOSPHERIC SCATTERING *TRANSMISSOMETERS *NEPHELOMETERS PORTABLE EQUIPMENT EXTINCTION AEROSOLS RESOLUTION REFRACTIVE INDEX LASER BEAMS TRANSMITTANCE MARINE ATMOSPHERES COEFFICIENTS SHIPBOARD ATTENUATION HELIUM NEON LASERS ABSORPTION COEFFICIENTS PE62759N wua0314b Gerber,H Feasibility of Shipboard Laser-Attenuation Measurements With a Portable Transmissometer. |
topic_facet |
Meteorology Lasers and Masers *ATMOSPHERIC SCATTERING *TRANSMISSOMETERS *NEPHELOMETERS PORTABLE EQUIPMENT EXTINCTION AEROSOLS RESOLUTION REFRACTIVE INDEX LASER BEAMS TRANSMITTANCE MARINE ATMOSPHERES COEFFICIENTS SHIPBOARD ATTENUATION HELIUM NEON LASERS ABSORPTION COEFFICIENTS PE62759N wua0314b |
description |
A 2-meter-long cell has been devised in which aerosol extinction and scattering coefficients can be measured simultaneously. Extinction is obtained by measuring the change in the intensity of a HeNe laser beam which is stepped through the cell for a total path length of 20 meters. A reciprocal nephelometer consisting of a sensor with a precise Lambertian response is mounted on the side of the cell to give a direct measure of the scattering coefficient. Filling the cell with ambient aerosol that has been concentrated centrifugally increases the effective path length of the beam in the cell to 300 meters. The cell was taken on the 1977 EOMET cruise of the USNS Hayes in order to determine its capabilities when exposed to the rigors of a ship's environment. The variance of data collected during the cruise was analyzed. The mean resolution limit of the transmittance measurements made during the cruise was + or - 0.16%. This limit was primarily influenced by mechanical instabilities in the nephelometer operated precisely. Vibrations from the ship's machinery was damped out successfully. An improved cell could increase the resolution by a factor of 10 or more. Absorption coefficients of the aersol particles in the eastern North Atlantic and in the Mediterranean were plotted. This technique has potential in the infrared. (Author) |
author2 |
NAVAL RESEARCH LAB WASHINGTON D C |
format |
Text |
author |
Gerber,H |
author_facet |
Gerber,H |
author_sort |
Gerber,H |
title |
Feasibility of Shipboard Laser-Attenuation Measurements With a Portable Transmissometer. |
title_short |
Feasibility of Shipboard Laser-Attenuation Measurements With a Portable Transmissometer. |
title_full |
Feasibility of Shipboard Laser-Attenuation Measurements With a Portable Transmissometer. |
title_fullStr |
Feasibility of Shipboard Laser-Attenuation Measurements With a Portable Transmissometer. |
title_full_unstemmed |
Feasibility of Shipboard Laser-Attenuation Measurements With a Portable Transmissometer. |
title_sort |
feasibility of shipboard laser-attenuation measurements with a portable transmissometer. |
publishDate |
1979 |
url |
http://www.dtic.mil/docs/citations/ADA067665 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA067665 |
long_lat |
ENVELOPE(-64.167,-64.167,-66.833,-66.833) |
geographic |
Hayes |
geographic_facet |
Hayes |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
DTIC AND NTIS |
op_relation |
http://www.dtic.mil/docs/citations/ADA067665 |
op_rights |
APPROVED FOR PUBLIC RELEASE |
_version_ |
1766133484060934144 |