HRD has developed a nested objective analysis software package to assimilate this wide array of observations, in the context of a relatively small hurricane vortex embedded in a broad-scale surrounding flow. The objective analyses that are produced are used to improve our understanding of tropical cyclone structure, motion, and evolution.
Recent work has focused on distinguishing potential vortex-environment interactions (e.g., the "beta-gyres") from stronger environmental flow features. To accomplish this, wind and vorticity asymmetries were calculated in two coordinate systems: the normal earth-based geographical system, and a coordinate system oriented parallel to the direction of storm motion.
Important distinctions between the total and wavenumber 1 asymmetric flows. While the beta-gyres could be detected in the total asymmetry, wavenumber 1 asymmetries were very closely related to the overall synoptic steering of the hurricane vortex, and tended to dominate the relatively weak beta-gyre signal.
The following manuscript has been accepted for publication:
Franklin, J. L., S. E. Feuer, J. Kaplan, and S. D. Aberson, 1996: Tropical cyclone motion and surrounding flow relationships: Searching for Beta-gyres in Omega dropwindsonde datasets. Mon. Wea. Rev., 124, (accepted).
Ooyama, K. V., 1987: Scale controlled objective analysis. Mon. Wea. Rev., 115, 2479-2506.
DeMaria, M., S. D. Aberson, K. V. Ooyama, and S. J. Lord, 1992: A nested spectral model for hurricane track forecasting. Mon. Wea. Rev., 120, 1628-1643.
Lord, S. J., and J. L. Franklin, 1987: The environment of Hurricane Debby (1982): Part I: Winds. Mon. Wea. Rev., 115, 2760-2780.
Franklin, J. L., S. J. Lord, S. E. Feuer, and F. D. Marks, Jr., 1993: The kinematic structure of Hurricane Gloria (1985) determined from nested analyses of dropwindsonde and doppler radar data. Mon. Wea. Rev., 121, 2433-2451.