Extended Abstract (196K)16A.3
High-resolution observations of the eyewall in an intense hurricane: Bret on 21–22 August 1999
Peter P. Dodge, NOAA/AOML/HRD, Miami, FL; and M. L. Black, J. L. Franklin, J. F. Gamache, and F. D. Marks
On 21 and 22 August, 1999, the Hurricane Research Division of the National Oceanographic and Atmospheric Administration (NOAA) conducted two single-plane experiments in Hurricane Bret with P-3 aircraft from NOAA's Aircraft Operations Center (AOC). The flight pattern on the 21st was intended to survey the vortex and it's environment; at this time Bret was a Category 4 hurricane, with winds > 63m/s. The flight on the 22nd occurred as Bret, now a Category 3 storm with winds still > 50 m/s, made landfall on the South Texas coast between Corpus Christi and Brownsville.
On both days there was a module where the aircraft flew upwind in the eye, just inward from the eyewall at flight level. The eyewall sloped inward below the aircraft so GPS sondes dropped during the pattern sampled the wind maxima at lower altitudes, finding winds > 74 m/s on the 21st, and > 60 m/s on the 22nd.
The tail Doppler radar was operated in Fore/Aft Scanning mode during both flights. Usually in hurricane penetrations we only get a few eyewall slices as the aircraft quickly crosses the eye, but during the eye circles many slices were collected at close range (<5 km) that provide a detailed picture of the three-dimensional windfield in a portion of the eyewall on successive days. We will present the dual-Doppler reflectivity and wind fields to show the eyewall features the sondes fell through, with the goal of describing the variability of the windspeed maxima in the hurricane eyewall.
Session 16A, Tropical Cyclone Observations and Structure V (Parallel with Sessions 16B and 16C)
Friday, 3 May 2002, 8:30 AM-10:30 AM
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