HR: 0800h
AN: A21C-0636    [Abstracts]
TI: High-resolution simulation of tropical cyclone Debby (2006) and validation with NAMMA data
AU: Pu, Z
EM: Zhaoxia.Pu@utah.edu
AF: Department of Meteorology University of Utah, 135 S 1460E, rm.819, Salt Lake City, UT 84112,
AU: * Zipser, E
EM: Ed.Zipser@utah.edu
AF: Department of Meteorology University of Utah, 135 S 1460E, rm.819, Salt Lake City, UT 84112,
AU: Zawislak, J
EM: Jon.zawislak@utah.edu
AF: Department of Meteorology University of Utah, 135 S 1460E, rm.819, Salt Lake City, UT 84112,
AB: Tropical cyclone Debby (2006) formed from an African wave only a short distance off the west African coast. Because it formed during the African Monsoon Multidisciplinary Analyses (AMMA) program, there are more data than usual for model initialization over the African continent. The NASA downstream addition to AMMA (NAMMA) provides a unique opportunity to validate these simulations with a detailed description of the structure of Debby with data from the DC-8 aircraft flight of August 23. This dataset is particularly valuable because it includes clear evidence of the wind, cloud, precipitation, and aerosol distribution as a function of height, never before obtained for a storm in the east Atlantic. A nested-grid WRF model at resolution of 36, 12, 4, and 1.33 km is initialized with NCEP global forecast system final analysis about 36 hours before the tropical storm formation. A total of 5 days of simulation is conducted to depict the structure and evolution of tropical cyclone Debby. Numerical simulation results are compared with the observations obtained during NAMMA. Among the questions to be addressed are the following: (1) The actual storm is warm core, but with the strongest winds are at 700-600 hPa; does the simulation have similar structure? (2) The actual storm has an eyewall extending to only about 500 hPa, with the cyclone center at 400-300 hPa displaced almost 100 km to the southeast; does the simulation have a similar structure? (3) The actual storm has dry, aerosol-laden air just outside the rain area in most quadrants; does the simulation agree with these observations? (4) How sensitive are the numerical simulation to the cloud microphysics and boundary layer parameterizations? To the choice of 4 km or 1.33 km for the finest grid?
DE: 0466 Modeling
DE: 3374 Tropical meteorology
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting