Remote Sensing and Modeling of Hurricane Intensification Steve Guimond and Jon Reisner Atmospheric Dynamics EES-2 FSU

Why study hurricanes? Societal –Protection of life and property Energy (DOE  LANL) –Northern Gulf of Mexico Largest portion of domestic oil & gas exploration, production, processing  Economy DOD (Navy)

Why study hurricanes? Societal –Protection of life and property Energy (DOE  LANL) –Northern Gulf of Mexico Largest portion of domestic oil & gas exploration, production, processing  Economy DOD (Navy) LSU

Solutions? Mitigating risks relies heavily on accurate, timely forecasts –Track –Intensity –Structure However, problems with forecasting…

Methods for solution Main reason for forecasting troubles: –Incomplete understanding and observation of hurricane physics Understanding State-of-the-art atmospheric model (Reisner et al. 2005) –Compressible Navier-Stokes –Explicit cloud microphysics –Superior numerics –Observation Unique airborne dual-doppler radar dataset –Rapidly intensifying Hurricane Guillermo (1997) –High resolution: »2 km spatial »30 minute temporal LANL dual-frequency lightning array

Basic Hurricane Dynamics Diabatic systems –Latent heat extracted from ocean and released in deep convection Forces direct and indirect circulations –Energy  mass  momentum

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

Airborne Doppler Radar 3-D reflectivity and latent heat animations Latent heat retrieved following Guimond (2008)

Simulations Environment and boundary conditions –ECMWF re-analysis Stretched Grid –2km radar domain extending to 15 km Quiet environment Constant SST (29ºC) Forcing from radar derived latent heat

Model Evaluation

Moist Potential Vorticity Animation

Angular Momentum Budgets Useful for explaining mechanics of storm spin-up Computed in cylindrical coordinate system –dr = 2 km –85 azimuthal points

Vortex Intensification

Angular Momentum Budgets: Run 1

Summary/Conclusions Radar retrieved heating produces realistic comparison to actual storm even in “idealized” setting Latent heat initialization believed superior to vortex insertion methods Role of eddies large initially, then axisymmetrization process takes over –Hydrostatic and gradient wind adjustment

Future Work: Lightning Basic physics –Lightning proxy for intense convective activity, requires… Supercooled liquid water, ice and graupel collisions Strong updraft and latent heating New LANL ground-based detection array –Operates in VLF & VHF radio bands –Precise 4D locations –Detects cloud-ground and intracloud strokes –24/7 monitoring over large regions Placed in Louisiana area, offshore oil rigs

Updraft Background Vortex Latent HeatParticle Growth Lightning Microphysics Eddy Heat and Momentum Fluxes Balanced response Adjustment Symmetric heating Asymmetric heating Adjustment Balanced response Adjustment Collisions Intensity and Structure Change Hurricane Intensification Roadmap Nolan and Grasso (2003)

Acknowledgments Thanks to Jon Reisner (EES-2), Chris Jeffrey (ISR-2) and the LANL Hurricane Lightning team