### Abstract

A modified formula for calculating tropical cyclone (TC) potential intensity (PI) from a balance between energy production and frictional dissipation in the TC surface layer is developed. This modified formula accounts for energy production and frictional dissipation at multiple radii (and therefore at multiple wind speeds) along the TC inflow trajectory. The PI maximum wind speed values V_{MAX} are calculated using this expanded formula for four canonical radial profiles of wind speed. These results are compared to PI V_{MAX} values calculated using the standard assumption that all energy production and frictional dissipation relevant to maximum intensity occurs at the radius of maximum winds (RMW). The new PI formulation developed here results in PI V_{MAX} values substantially higher than the standard PI V_{MAX} for all four of the radial wind speed profiles examined; the difference is explained by the increase in the outer radial limit of energy production. This increase holds true even if outflow temperature increases with increasing radius, although the V_{MAX} increases with increasing outer radius are somewhat more modest in this case. The extended PI formula yields V_{MAX} values 3-17 m s^{-1} higher than the standard PI V_{MAX} value when calculated with outer energy production-dissipation limits of 2.0-2.5 RMW, although it yields potentially unrealistic values when calculated with larger outer limits (e.g., 6 RMW). These results are presented as a potential explanation for why individual TCs can exceed their standard PI V_{MAX} values in terms of the storm thermodynamics.

Original language | English (US) |
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Pages (from-to) | 3569-3578 |

Number of pages | 10 |

Journal | Monthly Weather Review |

Volume | 144 |

Issue number | 10 |

DOIs | |

State | Published - Jan 1 2016 |

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### All Science Journal Classification (ASJC) codes

- Atmospheric Science

### Cite this

*Monthly Weather Review*,

*144*(10), 3569-3578. https://doi.org/10.1175/MWR-D-15-0383.1

}

*Monthly Weather Review*, vol. 144, no. 10, pp. 3569-3578. https://doi.org/10.1175/MWR-D-15-0383.1

**A reformulation of tropical cyclone potential intensity theory incorporating energy production along a radial trajectory.** / Kowaleski, Alex M.; Evans, Jenni.

Research output: Contribution to journal › Article

TY - JOUR

T1 - A reformulation of tropical cyclone potential intensity theory incorporating energy production along a radial trajectory

AU - Kowaleski, Alex M.

AU - Evans, Jenni

PY - 2016/1/1

Y1 - 2016/1/1

N2 - A modified formula for calculating tropical cyclone (TC) potential intensity (PI) from a balance between energy production and frictional dissipation in the TC surface layer is developed. This modified formula accounts for energy production and frictional dissipation at multiple radii (and therefore at multiple wind speeds) along the TC inflow trajectory. The PI maximum wind speed values VMAX are calculated using this expanded formula for four canonical radial profiles of wind speed. These results are compared to PI VMAX values calculated using the standard assumption that all energy production and frictional dissipation relevant to maximum intensity occurs at the radius of maximum winds (RMW). The new PI formulation developed here results in PI VMAX values substantially higher than the standard PI VMAX for all four of the radial wind speed profiles examined; the difference is explained by the increase in the outer radial limit of energy production. This increase holds true even if outflow temperature increases with increasing radius, although the VMAX increases with increasing outer radius are somewhat more modest in this case. The extended PI formula yields VMAX values 3-17 m s-1 higher than the standard PI VMAX value when calculated with outer energy production-dissipation limits of 2.0-2.5 RMW, although it yields potentially unrealistic values when calculated with larger outer limits (e.g., 6 RMW). These results are presented as a potential explanation for why individual TCs can exceed their standard PI VMAX values in terms of the storm thermodynamics.

AB - A modified formula for calculating tropical cyclone (TC) potential intensity (PI) from a balance between energy production and frictional dissipation in the TC surface layer is developed. This modified formula accounts for energy production and frictional dissipation at multiple radii (and therefore at multiple wind speeds) along the TC inflow trajectory. The PI maximum wind speed values VMAX are calculated using this expanded formula for four canonical radial profiles of wind speed. These results are compared to PI VMAX values calculated using the standard assumption that all energy production and frictional dissipation relevant to maximum intensity occurs at the radius of maximum winds (RMW). The new PI formulation developed here results in PI VMAX values substantially higher than the standard PI VMAX for all four of the radial wind speed profiles examined; the difference is explained by the increase in the outer radial limit of energy production. This increase holds true even if outflow temperature increases with increasing radius, although the VMAX increases with increasing outer radius are somewhat more modest in this case. The extended PI formula yields VMAX values 3-17 m s-1 higher than the standard PI VMAX value when calculated with outer energy production-dissipation limits of 2.0-2.5 RMW, although it yields potentially unrealistic values when calculated with larger outer limits (e.g., 6 RMW). These results are presented as a potential explanation for why individual TCs can exceed their standard PI VMAX values in terms of the storm thermodynamics.

UR - http://www.scopus.com/inward/record.url?scp=84994181858&partnerID=8YFLogxK

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U2 - 10.1175/MWR-D-15-0383.1

DO - 10.1175/MWR-D-15-0383.1

M3 - Article

VL - 144

SP - 3569

EP - 3578

JO - Monthly Weather Review

JF - Monthly Weather Review

SN - 0027-0644

IS - 10

ER -