Initial Field Measurements of Atmospheric Absorption at 9 Micrometers to 11 Micrometers Wavelengths.
Abstract
A field-adapted spectrophone system employing a tunable CO2 laser source (over wavelengths 9.2 micrometers to 10.8 micrometers was used to measure atmospheric gaseous and particulate absorption at an isolated desert southwestern location in the United States. Measurements were made both for ambient conditions (when aerosol particulate absorption was negligible compared to that of gases) and for dusty conditions resulting from vehicular traffic. For ambient conditions, the gaseous absorption coefficient varied with time from expected levels upward by as much as a factor of 3. Sources which could be correlated with increased absorption are discussed. For dusty conditions the spectrophone data were compared with estimates of the absorption coefficient calculated on the basis of measured particle size distributions together with estimates of particle complex indices of refraction. Temporal variation of the absorption coefficient correlated closely for the two methods, while the calculated values were generally higher. Sampling and calculational uncertainties are suggested as likely to be responsible for this discrepancy. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1980
- Accession Number
- ADA093709
Entities
People
- B. D. Hinds
- Charles W. Bruce
- R. G. Pinnick
- Ralph J. Brewer
- Young Paul Yee
Organizations
- Atmospheric Sciences Laboratory