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Isentropic Analysis of a Simulated HurricaneHurricanes, like many other atmospheric flows, are associated with turbulent motions over a wide range of scales. Here the authors adapt a new technique based on the isentropic analysis of convective motions to study the thermodynamic structure of the overturning circulation in hurricane simulations. This approach separates the vertical mass transport in terms of the equivalent potential temperature of air parcels. In doing so, one separates the rising air parcels at high entropy from the subsiding air at low entropy. This technique filters out oscillatory motions associated with gravity waves and separates convective overturning from the secondary circulation. This approach is applied here to study the flow of an idealized hurricane simulation with the Weather Research and Forecasting (WRF) Model. The isentropic circulation for a hurricane exhibits similar characteristics to that of moist convection, with a maximum mass transport near the surface associated with a shallow convection and entrainment. There are also important differences. For instance, ascent in the eyewall can be readily identified in the isentropic analysis as an upward mass flux of air with unusually high equivalent potential temperature. The isentropic circulation is further compared here to the Eulerian secondary circulation of the simulated hurricane to show that the mass transport in the isentropic circulation is much larger than the one in secondary circulation. This difference can be directly attributed to the mass transport by convection in the outer rainband and confirms that, even for a strongly organized flow like a hurricane, most of the atmospheric overturning is tied to the smaller scales.
Document ID
20160005728
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Mrowiec, Agnieszka A.
(Columbia Univ. New York, NY, United States)
Pauluis, Olivier
(New York Univ. New York, NY, United States)
Zhang, Fuqing
(Pennsylvania State Univ. University Park, PA, United States)
Date Acquired
May 3, 2016
Publication Date
April 13, 2016
Publication Information
Publication: Journal of the Atmospheric Sciences
Publisher: AMS
Volume: 73
Subject Category
Meteorology And Climatology
Report/Patent Number
GSFC-E-DAA-TN31512
Funding Number(s)
CONTRACT_GRANT: DE-PS02-09ER09-01
CONTRACT_GRANT: NNX12AJ79G
CONTRACT_GRANT: NNX14AB99A
Distribution Limits
Public
Copyright
Other
Keywords
convection
hurricanes
mass transfer
simulation
atmospheric temperature
entropy

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