Tropical cyclone spin‐up revisited

By Roger K. Smith, M. Montgomery, Nguyen Van Sang. 2009

335 citations recorded by the source corpus.

We present numerical experiments to investigate axisymmetric interpretations of tropical cyclone spin‐up in a three‐dimensional model. Two mechanisms are identified for the spin‐up of the mean tangential circulation. The first involves the convergence of absolute angular momentum above the boundary layer and is a mechanism to spin up the outer circulation, i.e. to increase the vortex size. The second involves the convergence of absolute angular momentum within the boundary layer and is a mechanism to spin up the inner core. It is associated with the development of supergradient wind speeds in the boundary layer. The existence of these two mechanisms provides a plausible physical explanation for certain long‐standing observations of typhoons by Weatherford and Gray, which indicate that inner‐core changes in the azimuthal‐mean tangential wind speed often occur independently from those in the outer core. The unbalanced dynamics in the inner‐core region are important in determining the maximum radial and tangential flow speeds that can be attained, and therefore important in determining the azimuthal‐mean intensity of the vortex. We illustrate the importance of unbalanced flow in the boundary layer with a simple thought experiment. The analyses and interpretations presented are novel and support a recent hypothesis of the boundary layer in the inner‐core region. Copyright © 2009 Royal Meteorological Society

Subfields: Atmospheric Science, Global and Planetary Change, Oceanography

View Paper: https://www.semanticscholar.org/paper/0c2f5f3c5f55801249be7b6ab7c277849e066e19

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atmospheric Science

1. M. Montgomery
2. D. Nolan
3. Roger K. Smith
4. Yuqing Wang
5. Jing Xu
6. Fuqing Zhang
7. R. Rogers
8. G. Thomsen

In Global and Planetary Change

1. M. Montgomery
2. Roger K. Smith
3. D. Nolan
4. G. Thomsen
5. Jing Xu
6. Jun A. Zhang
7. R. Rogers
8. Yuqing Wang

In Oceanography

1. M. Montgomery
2. D. Nolan
3. Roger K. Smith
4. Jing Xu
5. Fuqing Zhang
6. G. Thomsen
7. Yuqing Wang
8. J. Kossin

Citations in the corpus

• Sensitivity of tropical‐cyclone models to the surface drag coefficient in different boundary‐layer schemes (2014, background): “Prominent features are that vmax occurs at low levels near the top of the frictionally induced inflow layer in all cases, while umin occurs very close to the surface, in accord with the findings of Smith et al. (2009).”
• Paradigms for Tropical Cyclone Intensification (2014, background): “…of intensification and structure to the choice of boundarylayer parameterisation scheme; how robust are the findngs of Nguyen et al. (2008), Montgomery et al. (2009) and Smith et al. (2009) to the choice of boundary-layer scheme; and which scheme is optimum for operational intensity prediction?”
• Rapid Intensification of a Sheared Tropical Storm (2010, background): “The symmetric dynamics of tropical cyclone intensification, including the role of unbalanced boundary layer flow, has been clearly described by Smith et al. (2009).”
• Multiscale Structure and Evolution of Hurricane Earl (2010) during Rapid Intensification (2015, background): “A related argument was advanced by Montgomery et al. (2014), Sanger et al. (2014), Montgomery and Smith (2012), and Smith et al. (2009), who examined radial inflow in the boundary layer and showed how it spins up the vortex by converging Unauthenticated | Downloaded 12/13/20 07:42 PM UTC absolute…”
• The Roles of an Expanding Wind Field and Inertial Stability in Tropical Cyclone Secondary Eyewall Formation (2012, result): “Consistent with the studies of Smith et al. (2008, 2009) and Smith and Montgomery (2010), HMW12 suggest that an expanding wind field in and above the boundary layer leads to increased boundary layer inflow due to an inward pressure gradient force that exceeds the counteracting but frictionally…”
• Sensitivity of Tropical Cyclone Inner-Core Size and Intensity to the Radial Distribution of Surface Entropy Flux (2010, methodology): “In a recent modeling study, Smith et al. (2009) iden-tified two mechanisms responsible for the spinup of the mean tangential circulation, namely 1) the convergence of absolute angular momentum above the boundary layer for the spinup of the outer circulation, which increases the TC size, and 2) that…”
• Recent Developments in the Fluid Dynamics of Tropical Cyclones (2017, positive): “However, the maximum tangential wind speed in a tropical cyclone is found to occur within the inner-core boundary layer (Zhang et al. 2001, Smith et al. 2009).”
• Dependence of tropical‐cyclone intensification on the boundary‐layer representation in a numerical model (2010, background): “The statement in Smith et al. (2009) that these mechanisms are independent is too strong: there must be a degree of coupling between them through boundarylayer dynamics.”