Simultaneous Measurement of Laser Extinction in Warm Fog at Wavelengths of 0.6328, 1.15 and 10.6 Microns
COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER NH
Pagination or Media Count:
Simultaneous laser extinction measurements were made in warm fog at wavelengths of 0.6238, 1.15 and 10.6 micrometers. The warm fog generated in a 4 cu m environmental chamber. Particle sampling was carried out simultaneously with the laser measurements using an impactor. Using the same size distribution in each case the theoretical extinction coefficients were calculated and compared with the experimental coefficients. Results obtained during this experiment and a previous one indicate that propagation at 1.15 micrometers is adversely affected by the presence of atmospheric water vapor. Experimental data obtained simultaneously at 0.6328 and 10.6 micrometers indicate that virtually no difference exists between the extinction coefficients at these two wavelengths for moderate particle concentrations while at much larger concentrations alpha sub 0.6328 increases indefinitely while alpha sub 10.6 levels off at 0.2.
- Atmospheric Physics