Tropical Cyclone Structure2008 TCS08 ONRNRL Funded Projects

1

• Tropical cyclogenesis and subsequent structure
  change are multiscale processes that challenge
  current theoretical understanding and numerical
  weather prediction capabiities
• Several theories on the relative importance of
  convective and stratiform regions in tropical
  cyclogenesis have been proposed, but theoretical
  and numerical model predictions require further
  scrutiny
• New observations are needed to test our new TC
  genesis and secondary eyewall formation
  hypotheses necessary for understanding limits of
  predictability

A Multiscale Study of Tropical Cyclone Formation,
Structure Change and Predictability in the
Western North Pacific Region Michael T.
Montgomery (mtmontgo_at_nps.edu) Michael M. Bell
(mmbell_at_nps.edu) Naval Postgraduate
School Monterey, CA 93943

• Test new marsupial theory of TC formation
  emphasizing importance of sub-synoptic scale
  pouch and dominance of sustained deep
  convective (e.g. VHT) processes within the pouch
  during West-Pac TC formation
• Collect data, analyze and interpret mesoscale and
  cloud-scale processes within the pouch during
  TC formation using in-flight, dropsonde and
  Doppler radar observations. Perform companion
  high res. cloud resolving simulations
• Observe TC outer-wind structure, including
  secondary eyewall development and compare against
  our new hypothesis and high res. simulations

• Execute flight modules designed to evaluate the
  contribution of both mesoscale and cloud scale
  processes in the amplification of the low-level
  cyclonic circulation during TC genesis and
  secondary eyewall formation
• Obtain three-dimensional observations by the NRL
  P-3 and AF-C130 using ELDORA, Doppler wind lidar,
  dropsondes, and flight level data, of the deep
  convective and stratiform regions in developing
  TCs, and the outer wind structure of mature TCs