HOT TOWERS AND HURRICANE INTENSIFICATION Steve Guimond Florida State University

Motivation TC intensification is a complex, non-linear process governed by physics on a multitude of scales –Synoptic scale –Vortex scale –Convective scale –Hydrometeor scale Improving TC intensification (for wide range of applications including energy) hinges on better understanding of inner-core dynamics In nature, the occurrence of hot towers can often be linked to TC intensification (i.e. Guimond et al. 2009) But not always!

Motivation What are hot towers? How are they distributed? EYE

Latent Heat Updraft Background Vortex MicrophysicsHurricaneIntensificationRoadmap Eddy Heat and Momentum Fluxes Balanced response Adjustment Symmetric heating Asymmetric heating Adjustment Balanced response Adjustment Intensity and Structure Change Nolan and Grasso (2003)

Latent Heat Updraft Background Vortex MicrophysicsHurricaneIntensificationRoadmap Eddy Heat and Momentum Fluxes Balanced response Adjustment Symmetric heating Asymmetric heating Adjustment Balanced response Adjustment Intensity and Structure Change Nolan and Grasso (2003) Lightning Collisions & Charging

My Contribution Characterizing 4-D latent heating in RI Hurricane –Most estimates of latent heat in TCs are crude Satellite –Coarse (space/time) –Not enough information (no winds) –Airborne dual-Doppler retrieval 2 km x 2 km x 1 km x ~30 minutes Understanding inner-core dynamics that is triggered by hot towers –What spatial/temporal scales of heating does the hurricane “feel” ? –Implications for observing systems  lightning LANL network ~ 200 m resolution for VHF –Are small scale details of lightning/heating necessary to capture intensification or are bulk quantities sufficient?

Inner-Core Dynamics Balanced adjustment of hot towers at ~100 m vs. ~ 2 km and feedbacks onto vortex scale Dynamics heavily motivated by observations –Basic-state vortex using Doppler data Made stable to all wavenumber perturbations Made non-divergent by solving Poisson Unbalanced initially –Heating perturbations using EDOP data

Gravity Waves

EDOP Heating Pulse

Goal: Understand fundamental impacts of hot towers (HTs) on hurricane intensification (Convective and Vortex Scales) New version of latent heating retrieval –4-D distribution of heating in RI Hurricane (first time) Non-linear simulations addressing symmetric and asymmetric dynamics that result from HTs –Balanced adjustment of hot towers at ~100 m vs. ~2 km and feedbacks onto vortex scale Proxy for lightning = latent heat ? Help prove the value of lightning data in understanding/predicting dynamics of hurricanes –Physics on fine space/time scales are important –Role of the asymmetric mode Summary and Ongoing Work

Acknowledgments Gerry Heymsfield (EDOP and dropsonde data) Paul Reasor and Matt Eastin (Guillermo edits) Scott Braun (MM5 output) Robert Black (cloud particle processing) David Moulton (help with PDE code) References Roux and Ju (1990) Braun et al. (2006), Braun (2006) Gamache et al. (1993) Heymsfield et al. (1999) Reasor et al. (2008) Black (1990)

Peak Updrafts from EDOP Heymsfield et al. 2009

Inner-Core Dynamics Balanced adjustment of hot towers at ~100 m vs. ~2 km and feedbacks onto vortex scale

Latent Heat Updraft Background Vortex MicrophysicsHurricaneIntensificationRoadmap Eddy Heat and Momentum Fluxes Balanced response Adjustment Symmetric heating Asymmetric heating Adjustment Balanced response Adjustment Intensity and Structure Change Nolan and Grasso (2003) Lightning Collisions & Charging

Latent Heating Retrieval Based on Roux and Ju (1990) –Solve water budget with Doppler radar –Compute latent heat with vertical velocity & lapse rate Improvements to algorithm –Examine assumptions (uncover sensitivities) –Reduced uncertainties with ancillary data –Uncertainty estimates on final product