Cirrus microphysics and radiative transfer: cloud field study on 28 October 1986

Remote-sensing measurements from the stratosphere and the ground detect an inhomogeneous cloud structure between 6 and 11 km in altitude. The measurements differentiate between an optically thicker (τ >3) cirrus deck characterized by sheared precipitation trails and an optically thinner (τ <2) cirrus cloud field in which individual cells of liquid water are imbedded. Simultaneous measurements of particle-size spectra and broadband radiative fluxes at multiple altitudes in the lower half of the cloud provide the basis for a comparison between measured and calculated fluxes. The calculated fluxes are derived from observations of cloud-particle-size distributions, cloud structure, and atmospheric conditions. Comparison of the modeled fluxes with the measurements shows that the model results underestimate the solar reflectivity and attenuation, as well as the downward infrared fluxes. -from Authors