Aerosol and Clouds
Helical circulations in the typhoon boundary layer
Article first published online: 18 MAR 2010
Copyright 2010 by the American Geophysical Union.
Journal of Geophysical Research: Atmospheres (1984–2012)
Volume 115, Issue D6, 27 March 2010
How to Cite
2010), Helical circulations in the typhoon boundary layer, J. Geophys. Res., 115, D06205, doi:10.1029/2009JD011819., and (
- Issue published online: 18 MAR 2010
- Article first published online: 18 MAR 2010
- Manuscript Accepted: 21 OCT 2009
- Manuscript Revised: 7 OCT 2009
- Manuscript Received: 27 JAN 2009
- boundary layer
 Low-level wind data from the WSR-88D in Guam obtained in Typhoon Dale (1996) and Typhoon Keith (1997) are analyzed for coherent structures. Consistent with the results of previous studies of Atlantic hurricanes, velocity anomalies associated with coherent structures were found in the boundary layer of both storms. A total of 99 cases of coherent structures, also known as roll vortices, were documented during a 6 h evaluation period for each storm. Storm-relative roll location, roll vorticity, asymmetries in the upward and downward momentum fluxes, and signatures of circulations transverse to the mean flow associated with roll circulations were explored. The effects of terrain and convective precipitation systems, such as rainbands, on the occurrence of rolls were investigated. The results support and extend prior findings of roll observations, and can be used to help validate theoretical and numerical models of coherent structures within tropical cyclones. Moreover, the wind variations documented in this study may have application for wave runup and wind damage potential in tropical cyclones.