HOT TOWERS AND HOT TOWERS AND HURRICANE HURRICANE

INTENSIFICATIONINTENSIFICATION

Steve GuimondFlorida State University

MotivationMotivation

• 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!

MotivationMotivation

• What are hot towers?• How are they distributed?

EYEEYE

Latent Heat

Updraft

Background Vortex

Microphysics

Hurricane Hurricane IntensificatioIntensification n

RoadmapRoadmap

Eddy Heat and

Momentum Fluxes

Balanced responseAdjustme

nt

Symmetric heating

Asymmetricheating

Adjustment

Balanced response Adjustme

nt

Intensity and

Structure Change

Nolan and Grasso (2003)

Latent Heat

Updraft

Background Vortex

Microphysics

Hurricane Hurricane IntensificatioIntensification n

RoadmapRoadmap

Eddy Heat and

Momentum Fluxes

Balanced responseAdjustme

nt

Symmetric heating

Asymmetricheating

Adjustment

Balanced response Adjustme

nt

Intensity and

Structure Change

Nolan and Grasso (2003)

Lightning

Collisions &

Charging

My ContributionMy 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?

Latent Heating RetrievalLatent 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

Inner-Core DynamicsInner-Core Dynamics

• Balanced adjustment of hot towers at ~100 m vs. ~2 km and feedbacks onto vortex scale

Latent Heat

Updraft

Background Vortex

Microphysics

Hurricane Hurricane IntensificatioIntensification n

RoadmapRoadmap

Eddy Heat and

Momentum Fluxes

Balanced responseAdjustme

nt

Symmetric heating

Asymmetricheating

Adjustment

Balanced response Adjustme

nt

Intensity and

Structure Change

Nolan and Grasso (2003)

Lightning

Collisions &

Charging

Inner-Core DynamicsInner-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

– Heating perturbations using EDOP data

Peak Updrafts from Peak Updrafts from EDOPEDOP

Heymsfield et al. 2009

• 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 Summary and Ongoing Ongoing WorkWork

Acknowledgments• Gerry Heymsfield (EDOP and dropsonde data)• Paul Reasor and Matt Eastin (Guillermo edits)• Scott Braun (MM5 output)• Robert Black (cloud particle processing)

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)

Idealized Calculation