Showing papers by "Kenneth Sassen published in 1981"
TL;DR: Dual-wavelength extinction measurements reveal information on the growth and dissipation of laboratory water clouds and the effects of cloud seeding and the remote sensing significance of the findings is discussed.
Abstract: Measurements of the angular scattering and extinction of IR (10.6-μm) laser radiation in laboratory water and ice clouds are reported and compared to theoretical predictions for spheres and visible (0.633-μm) light scattering data. Randomly oriented cloud particles with dimensions ranging from several times smaller to larger than the incident wavelength generated phase functions span the Rayleigh and Mie scattering domains and illustrate the effects caused by strong internal energy absorption. Dual-wavelength extinction measurements reveal information on the growth and dissipation of laboratory water clouds and the effects of cloud seeding. The remote sensing significance of the findings is discussed.
14 citations
TL;DR: In this article, the evaporation rate of water drops suspended in a CO2 laser beam has been measured using an optical technique involving fixed-angle forward-scattering observations of the expanding diffraction pattern.
Abstract: The evaporation rate of water drops (~1.0–2.5-mm diameter) suspended in a CO2 laser beam has been measured using an optical technique involving fixed-angle forward-scattering observations of the expanding diffraction pattern. The results show a dr/dt ≈ 1.6-μm-sec−1 increase over the natural evaporation rate that is due to the internal particle heating produced by 10.6-μm energy absorption at an irradiance of ~1.65 W cm−2. Drop temperature records and dr/dt fluctuations over 30-μm-radius increments indicate a quasi-steady-state evaporation process in which free convection and internal drop circulation are important temperature-regulating mechanisms.
5 citations
TL;DR: In this article, the effects of irradiating artificial ice crystals with 10.6 μm CO2, laser radiation reveals that laser beam-ice crystal interactions can be quite disruptive to ice cloud content under some conditions.
Abstract: Preliminary investigation of the effects of irradiating artificial ice crystals with 10.6 μm CO2, laser radiation reveals that laser beam-ice crystal interactions can be quite disruptive to ice cloud content under some conditions. The responsible mechanism is the high absorption coefficient of ice at the 10.6 μm laser wavelength, but the effects produced by the resultant internal particle heating appear to be controlled by heat dissipation processes and are functions of both CW laser beam power density and ice crystal size. Observed effects resulting from CO2 laser irradiation range from the instantaneous fragmentation of large crystal branches to changes in the habit of growing ice crystals.
3 citations