SCALE RISING MOTION
METEOROLOGIST JEFF HABY
There are several mechanisms that cause
dynamic rising motion.
Warm air advection in the low levels of the
troposphere causes rising air. This is because warm air expands, creating a higher
thickness, which in turn causes
the air to rise.
Positive Vorticity Advection causes the air to rise. The
three terms that make up positive vorticity
in the Northern Hemisphere include counterclockwise curvature, counterclockwise shear on a horizontal
plane, and earth's counterclockwise Coriolis. Divergence and rising air occur in the right rear and left front
quadrants of a
jet streak. Any low level density boundary will lead to rising motion if
convergence occurs along
that low-level boundary. Low level boundaries include fronts,
outflow boundaries, moisture gradients, and
sea breeze fronts.
Upslope flow forces the air to rise.
Isentropic lifting, by way of warm air advection over a frontal
boundary or a cold shallow dome of air, will cause the air to rise. Convergence in the low levels will cause the
air to rise. The best examples are convergence along frontal boundaries and
frictional convergence into low pressure.