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Inner-core diagnostics of HWRFx

Inner-core diagnostics of HWRFx. Robert Rogers (with many others, e.g., John Gamache , Gopal , Sylvie Lorsolo , Frank Marks, Dave Nolan, Paul Reasor , Jun Zhang, Xuejin Zhang) *thanks to Thiago Quirino and Kevin Yeh. Motivation.

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Inner-core diagnostics of HWRFx

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  1. Inner-core diagnostics of HWRFx Robert Rogers (with many others, e.g., John Gamache, Gopal, Sylvie Lorsolo, Frank Marks, Dave Nolan, Paul Reasor, Jun Zhang, Xuejin Zhang) *thanks to ThiagoQuirino and Kevin Yeh

  2. Motivation • Much work has gone toward evaluating performance of numerical models using “traditional” metrics, e.g., position and intensity errors • Robust evaluations of inner-core structure needed to assess realism of numerical simulations, especially as grid lengths approach 1-3 km and finer • Wealth of TC inner-core data collected at HRD over the years provides excellent opportunity for evaluating high-resolution numerical models • Multi-storm composites key to provide statistically robust measures (with obvious caveats)

  3. Methodology • use composites of tail Doppler radar and GPS dropsonde data from NOAA WP-3D radial penetrations in many storms to compare inner-core structures from mature hurricanes with those produced from various configurations of HWRFx • variational analysis (Gamache 1997) of fields used to generate Cartesian grids of 3-D winds and reflectivity for Doppler analyses, with a horizontal grid spacing of 2 km and a vertical spacing of 0.5 km • cartesian data interpolated to cylindrical coordinates for axisymmetric calculations. Storm center defined using simplex algorithm (Neldar and Mead, 1965) for Doppler data and model output • compositing technique based on normalized radius • r* = r/|rmax_2km|, where |rmax_2km| = radius of maximum axisymmetric wind • at 2 km altitude • focus here is on several scales within TC inner core: • symmetric and asymmetric vortex-scale • convective-scale statistics • boundary-layer properties

  4. Observational databases used in composites Doppler database GPS dropsonde database 794 dropsondes in 13 different storms 40 radar analyses in 8 different storms Rogers et al., MWR, 2011 (in review) Zhang et al., MWR, 2011 (in review)

  5. Simulation databases used in composites HWRFx Real-data database Idealized HWRFx runs 34 model output times in 16 runs of 5 different storms • 2 runs • GFS PBL- MYJ PBL • both runs at 27:9:3 km, use Ferrier microphysics, SAS convection scheme on all meshes • both runs taken at 6-hourly intervals between 48 and 96 h during simulation - All runs at 27:9:3 km with GFS PBL, Ferrier microphysics and SAS convection on all meshes

  6. Some summary statistics on vortex structure

  7. Symmetric vortex-scale Tangential wind (% of maximum) HWRFx_Ideal_GFS Doppler Max 71.8 m/s Max 60.8 m/s height (km) height (km) height (km) r* HWRFx_Ideal_MYJ HWRFx_Real Max 66.0 m/s Max 66.9 m/s r* r* height (km) r*

  8. Symmetric vortex-scale Vorticity (% of maximum) HWRFx_Ideal_GFS HWRFx_Ideal_MYJ Doppler Max 6.4 x 10-3 1/s Max 4.1 x 10-3 1/s Max 5.1 x 10-3 1/s HWRFx_Real height (km) Max 2.4 x 10-3 1/s height (km) height (km) r* r* r* height (km) r*

  9. Asymmetric vortex-scale Wavenumber-1 vertical velocity (m s-1) and vorticity (x 10-4 s-1) as a f(vertical shear) *Shear rotated to be pointing east Doppler HWRFx_Real

  10. Convective-scale statistics as f(proximity to RMW) Vertical velocity CFADs (%, no precipitation masking for HWRFx) Inner eyewall Outer radii height (km) height (km) Doppler w (m/s) w (m/s) Outer radii Inner eyewall height (km) height (km) HWRFx_Real w (m/s) w (m/s)

  11. Symmetric boundary-layer Radial wind (% of minimum, i.e.,peak inflow) HWRFx_Ideal_MYJ HWRFx_Ideal_GFS Dropsonde Min -15.3 m/s Min -24.8 m/s Min -19.2 m/s HWRFx_Real Min -12.9 m/s height (km) height (km) height (km) r* r* r* height (km) r*

  12. Summary • Primary circulation well-represented, eyewall slopes more in model for all configurations compared to observations • Vorticity shows ring-like structure in Doppler, more monopolar structure in model • Both datasets show vertical velocity, vorticity asymmetry downshear, model rotated ~30 degrees downwind from Doppler • Magnitude of peak low-level inflow comparable, but inflow layer much deeper in model than observations • Broader distribution of vertical velocity in observations, both in inner eyewall and outer radii Future work • Continue expanding all databases (Doppler, dropsonde, HWRFx) • More intelligently subsample databases, e.g., better isolate steady-state cases, stratify by intensity, intensity change • Evaluate alternate model configuations • Different PBL, microphysical parameterizations • Different horizontal, vertical resolutions

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