Transient Eddies
q Mid-latitude cyclone and anticyclone are the
major transient eddies that play an important
role in meridional transports of heat,
momentum, and moisture.
q These mid-latitude weather systems grow
from the baroclinic instability associated
with the strong north-south temperature
gradients  in mid-latitudes.
q Mid-latitude cyclones have typical spatial
scales of wavenumbers 5-6 and have typical
time scale of 7-10 days.
q Mid-latitude cyclones are marked by well-
defined fronts separating the warm air mass
from the south and the cold air mass from
the north. (Very different from tropical
hurricanes, which do not have frontal
features).