original radius during exposure to a constant intensity /, Jis the beam diameter, and the absorption coefficient /?„ and water content W are related by Qa is the Mie absorption factor, N„ is the total particle concentration, p is the droplet density, and ac is the mode radius, i.e., the radius corresponding to the maximum number of particles. Numerical solution of the approximate equation for the evaporation rate was obtained by Kuzikovskii and Khmelevitsov (55) allowing for the nonlinear dependence of the temperature on water-vapor concentration for laser intensities I ~ 102—104 W/cm2. The parameterized relationship of the vaporization time tv and instantaneous droplet radius a was expressed as In Eqs. 16 and 17, t„ is in sec, I is in W/cm2, and X and ac are in gm. The complex index of refraction is n = n' - ik. For the droplet to be ineffectual in attenuating the beam, we require that the particle be reduced in size until a = 0.01X. It is more convenient to specify meteorological aerosols in terms of their liquid-water/ice path lengths, p (g/cm2), so that where v is in m/sec, d is in m, ac and X are in p.m, p is in g/cm2, p is in g/cm3, and / is in W/cm2. Qa, given previously by Eq. 6 for the large-radius approximation, is not valid for cloud and fog droplets. As an analytic convenience, we use the Shifrin approximation [see Gordin and Strelkov (56)] given by
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