Atlantic Hurricane
Isabel (2003)
During the period 9-18
September 2003, GOES-12 Super Rapid Scan Operations (SRSO) provided a
remarkable glimpse into the flow patterns that can occur in the
hurricane eye. This page provides links to animations and a few other
relevant items.
Animations
at the Cooperative Institute for Meteorological Satellite Studies
(University of Wisconsin-Madison)
Animations
at the Cooperative Institute for Research in the Atmosphere (Colorado
State University)
A physical
interpretation for the patterns that were evident in Hurricane Isabel's
eye is provided by Kossin
and Schubert
(2001), who demonstrated that eyewall flows in intensifying
hurricanes can support barotropic instability at high azimuthal
wavenumbers and fast growth rates. Using a numerical model of maximum
simplicity, they hypothesized that the hurricane eyewall can "roll-up"
into a number of mesovortices that subsequently merge to form
long-lived asymmetric patterns.
An example of one of the
remarkable convoluted patterns that emerged in Isabel's eye is shown
below
in Figure 1, and reveals a pentagonal "starfish" pattern.
Figure 1)
Defense Meteorological Satellite Program (DMSP) image of Hurricane
Isabel at 1315 UTC 12 Sep 2003. The ``starfish'' pattern in the eye is
caused by the presence of six mesovortices - one near the eye center
and
five surrounding it.
Another remarkable
evolution took place in Isabel's eye on 13 September, and is shown
below in Figure 2.
The numerical experiments of Kossin and Schubert (2001) produced
strikingly similar patterns and evolutions. Examples are shown below.
Other relevant links:
Jim Kossin's home page
(for additional literature on barotropic instability of the hurricane
eyewall)
CIMSS Tropical Cyclone Page
