Spectrally resolved visible and infrared images of marine stratus clou
ds were acquired from the NASA ER-2 high-altitude aircraft during the
1987 First International Cloud Climatology Program Regional Experiment
. The images were obtained by cross-track scanning radiometers. Data i
mages at near-infrared wavelengths show frequent and readily apparent
brightness features that are due to glory single scattering. The obser
vations and subsequent analysis by radiative transfer calculations sho
w that the glory is a significant feature of near-infrared solar refle
ctance from water clouds. Glory observations and calculations based on
in-cloud microphysics measurements agree well. The most dramatic diff
erence from the visible glory is that the scattering angles are signif
icantly larger in the near infrared. The glory is also apparently more
distinct in the near infrared than in the visible, as scattering size
parameters are in a range that effectively produces a glory feature,
and also there is less obscuration by multiple-scattering reflectance
because of absorption of radiation by droplets in the near infrared. F
or both the visible and the near infrared, the principal factors that
wash out the glory are dispersion and, to a lesser degree, the effecti
ve radius of the cloud droplet-size distribution. The obscuration by m
ultiple scattering in optically thick clouds is secondary. Rather than
being a novelty, glory observations would be an accurate and unambigu
ous technique to sense the droplet size of water clouds remotely.