Use of aerosol microphysical measurements to model IR backscatter in support of GLOBE
- Georgia Inst. of Tech., Atlanta (USA)
- Univ. of Alabama, Huntsville (USA)
The authors have used the GAMETAG Pacific mid-tropospheric aerosol data set to calculate aerosol optical extinction coefficients ({sigma}) at two wavelengths (0.55 {mu}m and 1 {mu}m) and volume backscatter coefficients ({beta}) at 4 wavelengths (1 {mu}m, 9.11 {mu}m, 9.25 {mu}m, and 10.6 {mu}m). At an altitude of 5 km over the Pacific, northern hemispheric mean values of {beta} for 10.6 {mu} are near 10{sup {minus}10} m{sup {minus}1}sr{sup {minus}1} at an altitude of 5 km, with southern hemispheric values approximately an order of magnitude lower. The 9.11 {mu}m values are roughly a factor of 3 higher than the 10.6 {mu}m values; 9.25 {mu}m values are approximately the same as 9.11 {mu}m values. For the data averaging times of 5-10 min are necessary for the calculated {beta} values as seen by a satellite lidar system. Under the assumptions of this study the molecular form of the sulfate aerosol is not a major determining factor in the calculated {beta} values at 10.6 {mu}m but could be significant at 9.11 {mu}m. A study of relationships among the optical parameters indicates that visible and near-visible values of {beta} and {sigma} may be useful in predicting 9.11- and 10.6 {mu}m backscatter, so that short wavelength aerosol data bases form satellites and Nd-YAG lidars may be useful in extending the data base of direct backscatter measurements at CO{sub 2} wavelengths.
- OSTI ID:
- 5331078
- Journal Information:
- Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 96:D3; ISSN 0148-0227; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AEROSOLS
ALTITUDE
BACKSCATTERING
CARBON DIOXIDE LASERS
COLLOIDS
DISPERSIONS
EARTH ATMOSPHERE
EARTH PLANET
ELECTROMAGNETIC RADIATION
GAS LASERS
LASERS
MEASURING INSTRUMENTS
METEOROLOGY
MONITORING
NORTHERN HEMISPHERE
OPTICAL PROPERTIES
OPTICAL RADAR
OXYGEN COMPOUNDS
PACIFIC OCEAN
PHYSICAL PROPERTIES
PLANETS
RADAR
RADIATIONS
RANGE FINDERS
SATELLITES
SCATTERING
SEAS
SOLS
SOUTHERN HEMISPHERE
SULFATES
SULFUR COMPOUNDS
SURFACE WATERS
TROPOSPHERE
VISIBLE RADIATION
WAVELENGTHS
WIND