The evolution of anvil clouds detrained from deep convective systems has
important implications for the tropical energy balance and is thought to
be shaped by radiative heating. We use combined radar-lidar observations
and a radiative transfer model to investigate the influence of radiative
heating on anvil cloud altitude, thickness, and microphysical structure.
We find that high clouds with an optical depth between 1 and 2 are
prevalent in tropical convective regions and can persist far from any
convective source. These clouds are generally located at higher
altitudes than optically thicker clouds, experience strong radiative
heating, and contain high concentrations of ice crystals indicative of
turbulence. These findings support the hypothesis that anvil clouds are
driven towards and maintained at a preferred optical thickness that
corresponds to a positive cloud radiative effect. Comparison of daytime
and nighttime observations suggests that anvil thinning proceeds more
rapidly at night, when net radiative cooling promotes the sinking of
cloud top. It is hypothesized that the properties of aged anvil clouds
and their susceptibility to radiative destabilization are shaped by the
time of day at which the cloud was detrained. These results underscore
the importance of small-scale processes in determining the radiative
effect of tropical convection.