Potential Physical Processes Explaining the Observed Spectral Signature of Cloudy Column Solar Radiation Absorption
The results presented here have shown that the spectral signature of absorption in a cloudy layer could be duplicated (except for the 1.06 {micro}m region) with a rather sophisticated radiative transfer model, if the absorption by both aerosol and cloud droplets was enhanced. In the case of aerosol, highly absorbing (imaginary part of refractive index between 0.1 and 0.01), small (2 - 5 nm) particles dramatically improved the match between observations and model computations. Duplication of the observed cloud absorption required a thin layer of drizzle (large droplets). The only feature remaining unexplained at this time is the enhanced absorption at 1.06 {micro}m. These results are only based on one day of observations and need to be verified. This study suggests the need for additional co-located broadband and spectral observations in clear and cloudy sky conditions in different atmospheric regimes. In-situ aerosol and cloud droplet microphysical measurements will be crucial to unravel the role of these particles in the ''enhanced absorption'' issue. Finally, accurate absorption measurements are needed at 1.06 {micro}m to understand observed absorption in that spectral region.
- Research Organization:
- University of California, Santa Barbara, CA (US)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- FG03-95ER61986
- OSTI ID:
- 761458
- Resource Relation:
- Conference: A Symposium with Tributes to the Works of Verner E. Suomi, Conference information not supplied, Conference dates not supplied; Other Information: PBD: 1 Jun 1960
- Country of Publication:
- United States
- Language:
- English
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