The STS 41-B crew shot this oblique photograph just moments
after the previous picture was taken. Some more fully developed
thunderheads can be seen in the same Brazilian storm. When the
rising cumulus columns meet the tropopause, or base of the stratosphere,
at about 15,000 kilometers (50,000 feet), they reach a ceiling
and can no longer rise buoyantly by convection. The stable temperature
of the stratosphere suppresses further adiabatic ascent of moisture
that has been driven through the troposphere by the 5-6.8 degree/kilometer
(8-11 degree/mile) lapse rate. Instead, ice clouds spread horizontally
into the extended cirrus heads seen in this photograph, forming
the "anvil heads" that we identify from the ground.
The finer, feathery development around the edges of some of the
thunderheads is glaciation - water vapor in the cloud is turning
to ice at high altitude. (Courtesy LPI/NASA)