Background
and format information on the 4-panel simulation figures:
The four-panel maps of the simulation results are organized
as in early publications of COMPASS-type investigations. Each
page contains four images, all featuring the same values for
the "e," "c," "k," "f,"
"p," and "h" parameters, but with the 2x2
matrix of combinations of the two values of each of the "m"
and "n" parameters. The two left-hand images are both
for small values of "m", while the two right-hand
images are both for large values of "m." The two lower
images are for small values of "n," while the upper
images are for large values of "n." As "m"
increases, the low-level lapse rates (above the LFC) increase,
and the altitude of maximum parcel buoyancy decreases. As "n"
increases, the low-level vertical shear of the environmental
wind increases, and the altitude of the maximum v-wind in our
semicircular hodographs decreases.
The
fields depicted in each image are designed to give a basic understanding
of storm structure and intensity. The color shades represent
low-level rainwater content, and describe the size, shape and
intensity of the storm's precipitation shield. The line contours
show the location and strength of the storm's updraft, using
a contour interval of 3 m/s. The updraft contours are shown
at an altitude roughly 2 km above cloud base; this tends to
give a representative view of the storm's midlevel updraft,
but is not necessarily the level where the updraft is strongest.
Note that these simulations are for storms that exist in sheared
environments, so that the locations of the peak updrafts and
precipitation cores are not generally exactly coincident. The
displacement of the precipitation core from the main updraft
is an important feature of many convective storms. The vectors
depict the near-surface ground-relative winds, with undisturbed
warm air having wide arrowheads, and the storm's rain-cooled
outflow having narrow arrowheads. Note that some storms ingest
a high proportion of undisturbed warm air (many of the vectors
beneath the midlevel updraft have wide arrowheads), while others
are undercut completely by rain-cooled air (most or all of the
vectors beneath the midlevel updraft have narrow arrowheads).
These kinds of morphological differences can have a profound
impact on storm intensity and longevity.
The
simulations are designed to depict the evolution of the first
two hours of a storm's life, but not all the storms survive
the full two hours. In particular, some of the small "m"
and small "n" storms, especially in cases of small
"e", dissipate quickly during the second hour. For
each of the panels shown in the map figures, the mature phase
of the most significant right-moving storm is displayed, and
the time of the simulated model storm's evolution is printed
next to each panel for reference. For storms that remain healthy
during the second hour, this time will always lie somewhere
between 60 and 120 minutes. For the storms that quickly dissipate,
we have elected to show storm structure at some point during
the first hour. Thus, storms that do not survive for two hours
are always identified by having a time stamp less than or equal
to 60 minutes in the figures.