The vorticity budget of developing typhoon Nuri (2008) New Mexico Tech, Socorro, New Mexico, USA
Received: 20 April 2010 – Published in Atmos. Chem. Phys. Discuss.: 02 July 2010 Abstract. The formation of west Pacific tropical cyclone Nuri (2008) was observed
over four days from easterly wave to typhoon stage by aircraft using
scanning Doppler radar and dropsonde data. This disturbance developed
rapidly in a significantly sheared environment. In spite of the shear,
overlapping closed circulations existed in the frame of reference
of the storm in the planetary boundary layer and at 5 km elevation,
providing a deep region protected from environmental influences. The
rapid spinup of Nuri can be attributed to the strong increase with
height at low levels of the vertical mass flux during and after the
tropical depression stage, and the correspondingly strong vorticity
convergence in the planetary boundary layer. As Nuri developed, convective
regions of boundary layer vortex stretching became fewer but more
intense, culminating in a single nascent eyewall at the tropical storm
stage. A non-developing tropical wave case was also analyzed. This
system started with much weaker circulations in the boundary layer
and aloft, leaving it unprotected against environmental intrusion.
This may explain its failure to develop.
Revised: 23 November 2010 – Accepted: 10 December 2010 – Published: 10 January 2011
Citation: Raymond, D. J. and López Carrillo, C.: The vorticity budget of developing typhoon Nuri (2008), Atmos. Chem. Phys., 11, 147-163, doi:10.5194/acp-11-147-2011, 2011.