HR: 11:30h
AN: A12D-05    [Abstracts]
TI: Hurricane Modeling and Supercomputing: Can a global mesoscale model be useful in improving forecasts of tropical cyclogenesis?
AU: * Shen, B
EM: bwshen@agnes.gsfc.nasa.gov
AF: UMCP/ESSIC and NASA/GSFC, Laboratory for Atmospheres, Code 613 NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States
AU: Tao, W
EM: tao@agnes.gsfc.nasa.gov
AF: NASA/GSFC, Laboratory for Atmospheres, Code 613 NASA Goddard Space Flight Center, Greenbelt, MD 20771, United States
AU: Atlas, R
EM: robert.atlas@noaa.gov
AF: NOAA Atlantic Oceanographic and Meteorological Laboratory, 4301 Rickenbacker Causeway, Miami, FL 33149, United States
AB: Hurricane modeling, along with guidance from observations, has been used to help construct hurricane theories since the 1960s. CISK (conditional instability of the second kind, Charney and Eliassen 1964; Ooyama 1964,1969) and WISHE (wind-induced surface heat exchange, Emanuel 1986) are among the well-known theories being used to understand hurricane intensification. For hurricane genesis, observations have indicated the importance of large-scale flows (e.g., the Madden-Julian Oscillation or MJO, Maloney and Hartmann, 2000) on the modulation of hurricane activity. Recent modeling studies have focused on the role of the MJO and Rossby waves (e.g., Ferreira and Schubert, 1996; Aivyer and Molinari, 2003) and/or the interaction of small-scale vortices (e.g., Holland 1995; Simpson et al. 1997; Hendrick et al. 2004), of which determinism could be also built by large-scale flows. The aforementioned studies suggest a unified view on hurricane formation, consisting of multiscale processes such as scale transition (e.g., from the MJO to Equatorial Rossby Waves and from waves to vortices), and scale interactions among vortices, convection, and surface heat and moisture fluxes. To depict the processes in the unified view, a high-resolution global model is needed. During the past several years, supercomputers have enabled the deployment of ultra-high resolution global models, obtaining remarkable forecasts of hurricane track and intensity (Atlas et al. 2005; Shen et al. 2006). In this work, hurricane genesis is investigated with the aid of a global mesoscale model on the NASA Columbia supercomputer by conducting numerical experiments on the genesis of six consecutive tropical cyclones (TCs) in May 2002. These TCs include two pairs of twin TCs in the Indian Ocean, Supertyphoon Hagibis in the West Pacific Ocean and Hurricane Alma in the East Pacific Ocean. It is found that the model is capable of predicting the genesis of five of these TCs about two to three days in advance. Our real-data simulations are the first of this type of global model experiment to support the following hypothesis: the MJO may play an essential role in the formation of this kind of TC, and therefore its occurrence could represent a crucial precursor to TC genesis.
DE: 3314 Convective processes
DE: 3329 Mesoscale meteorology
DE: 3337 Global climate models (1626, 4928)
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 3374 Tropical meteorology
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting