HR: 0830h
AN: A31E-0098    [PDF]
TI: Raman Lasing and Cavity Resonances in Water Micro-Droplets: Possible Effects on Shortwave Cloud Forcing
AU: * Cappa, C D
EM: cappa@uclink.berkeley.edu
AF: University of California, Berkeley, Department of Chemistry Hildebrand Hall, Berkeley, CA 94720-1460
AU: Wilson, K R
EM: kevinw@lanl.gov
AF: University of California, Berkeley, Department of Chemistry Hildebrand Hall, Berkeley, CA 94720-1460
AU: Messer, B M
EM: cadmium@uclink.berkeley.edu
AF: University of California, Berkeley, Department of Chemistry Hildebrand Hall, Berkeley, CA 94720-1460
AU: Cohen, R C
EM: cohen@cchem.berkeley.edu
AF: University of California, Berkeley, Department of Chemistry Hildebrand Hall, Berkeley, CA 94720-1460
AU: Saykally, R J
EM: saykally@uclink.berkeley.edu
AF: University of California, Berkeley, Department of Chemistry Hildebrand Hall, Berkeley, CA 94720-1460
AB: The influence of narrow optical resonances, which result from trapping of light rays via total internal reflection in water droplets, on the absorption of shortwave (SW) solar radiation has been characterized through high resolution Mie scattering calculations. Our results indicate that these resonances engender an increase in absorption of solar radiation by cloud droplets by several W/m$^{2}$ above the linear direct absorption process in the range 0.3-1.1 $\mu$m. This work suggests that Mie scattering calculations performed at the 0.1x (x = 2$\pi$r/$\lambda$) resolution typically implemented in cloudy sky radiative transfer models may not be sufficient to correctly model SW absorption, consistent with the recent finding of Nussenveig [2003]. Stimulated Raman scattering experiments on pure water microdroplets yield cavity enhancements in general agreement with the Mie theory results.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0320 Cloud physics and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting