Andrew presented a seminar on “Tropical Cyclone Eyewall Slope as Determined by Airborne Radar Reflectivity Data: Composites and Case Studies”.
ABSTRACT:
Understanding and predicting the evolution of the tropical cyclone (TC) inner core structure and intensity continues to be a major research focus in tropical meteorology. Eyewall slope and its relationship to intensity and intensity change is one potentially important inner-core structural feature. Accordingly, in this study, radar reflectivity data are used to quantify and analyze the azimuthal average and variance of eyewall slopes from 123 flight legs among 15 Atlantic TCs from 2004 to 2011. The slopes from each flight leg are averaged into 6-h increments around the Best-Track times to allow for a comparison of slope and best-track intensity. A statistically significant relationship is found in a composite sense between both the azimuthal mean slope and pressure and between slope and wind. In addition, a correlation is found between slope and radar-based eye size at 2 km, but eye size shows little correlation with intensity. There is a tendency for the eyewall to tilt downshear by an average of approximately 10°. Also, the upper eyewall slopes more sharply than the lower eyewall in about three-quarters of the cases. Case studies illustrate the relationship between slope and intensity in individual storms, and also show potential effects on eyewall slope of both inner-core and environmental processes, such as vertical shear and eyewall replacement cycles. These results indicate that eyewall slope is an important measure of TC inner-core structure, and may prove useful for future study of the processes that drive changes in the TC core.
A recording of the presentation and a copy of the presentation are available on the anonymous ftp site:
ftp://ftp.aoml.noaa.gov/hrd/pub/blog/seminars/2013/Hazelton_HRD_seminar_20130725.wmv
