Simultaneous observation of a glory and in-situ microphysical cloud properties

Abstract

While making airborne measurements of cloud particles, a bright glory was observed on a thin layer cloud. By deliberately flying through this glory-producing cloud on several occasions, cloud particle size distributions were obtained. We found that warm liquid clouds with narrow cloud droplet size distributions are responsible for producing the observed glory. This paper presents these results and compares the results of Mie theory simulations with an image of the glory.

Faint yet widespread glories reflect microphysics of marine clouds

“…The measured pairs in this case yielded (r = 6.9 μm,σ = 1.75 μm) for the left half and (r = 6.6 μm, σ = 2.21 μm) for the right half of the glory. These values of about 13 microns for the mean droplet diameter are consistent with airborne and in-situ measurements 6,7 of similar clouds. The DSD relative dispersion range of ϵ≡σ/r of 0.25 and 0.31 on the left and right, respectively, are also broadly consistent with in-situ (flight) measurements, reported in 9,10 .…”

“…This is complementary to the existing radiative transfer based methods because droplets sizes are retrieved here from well-characterized cloud tops and optically thin clouds. Moreover, the glory properties are sensitive to both first and second moments of the cloud's droplet size distribution (DSD), i.e., the mean radius and the variance 6,7 . Retrieving such pairs yields insights into cloud's properties.…”

“…Although coronas and glories have been studied for centuries 4,11,12 , carefully and extensively simulated 13 as well as compared with aircraft observations recently to invert for droplet size distribution parameters 7 , the globe-wide availability of glories on the daily basis and a simple application to satellite imaging via the associated simple diffraction scaling, to the best of our knowledge, has gone undetected. It is remarkable that, unlike rainbows, the index of refraction, seemingly so essential to the Mie scattering Fig.…”