Abstract:
The observations presented here were undertaken
as a continuation of a broader program to investigate
atmospheric convection. One phase of this
study concerns the relation between convective
motions, their energy sources, and the structure of
the atmosphere prior to their onset. The structure
of the atmosphere is described in terms of such
parameters as temperature, humidity, velocity,
turbulence, and distribution of these in space.
An oceanic island was chosen as the site for this
phase of the study primarily because it serves as
a localized and clearly defined energy source for
convective motions. Nantucket was selected
from the many accessible islands in the Woods
Hole area, nearly all known to produce convective
cloud streets, mainly because of its flat, smooth
topography. Because its elevation never exceeds
15 meters above sea level and because it contains
no large trees, hills or other obstructions, the
effect of heating the air from below is rather well
isolated due to minimization of the barrier and
frictional effects. Previous observational work
(Malkus, Bunker, and McCasland, 1949) indicates
that such heating is the main energy source
for the observed convective motions and constitutes
a necessary but not suffcient condition for
their production. This conclusion is corroborated
and extended by the present data.
